Hongru Zhou, Min Wang*, Fanhao Kong, Zhiwei Chen, Zhaolin Dou, and Feng Wang*
JACS, 2022, DOI:10.1021/jacs.2c08655
The electron transfer (ET) from the conduction band of the semiconductor to surface-bound species is a key step in the photocatalytic reaction and strongly affects the reactivity and selectivity, while the effect of catalyst surface structure on this process has rarely been explored due to the lack of an effective method. Herein, we have developed a strategy to detect and measure surface electrons’ transfer energy to the adsorbates and disclosed a facet-dependent electron transfer energy over anatase TiO2. The photogenerated electrons are shallowly confined in the five-coordinated Ti atom (Ti5c) on the surface of the (101) facet with a transfer energy below 1.0 eV, while deeply confined in the six-coordinated Ti atom (Ti6c) on the subsurface of the (001) facet with a transfer energy higher than 1.9 eV. The different electron trap states strongly affect the ET process, thus regulating the photocatalytic activity......
Cheng Cai, Ning Li, Huifang Liu, Jian Zhang, J.Y. Zhu*， and Feng Wang*
Chem. Eng. J., 2023, 453, 139730:1-8
Maleic acid (MA), a solid dicarboxylic acid can be obtained from renewable lignocellulose, was used to extract lignin through flow through (FT) process for the first time. Due to the high boiling point and flash point of MA, the FT process was carried out at atmospheric pressure without VOCs release and explosion risk. 50 wt% MA aqueous solution could extract 60% lignin from birch wood, and the dilution factor for precipitating lignin was only 3. MA-extracted lignin preserved more than 80% of β–O–4 bonds and a monophenol yield (>30%) comparable to that of milled wood lignin was obtained by catalytic hydrogenolysis. The recyclability of MA was demonstrated through three rounds of lignin extraction by recovered MA. And the cellulose-rich residue could be efficiently converted into glucose (glucose yield>90%) at a low cellulase loading of 10 FPU/g glucan due to the rich carboxyl groups of lignin. In addition, the …
Zhuyan Gao, Junju Mu, Jian Zhang, Zhipeng Huang, Xiangsong Lin, Nengchao Luo*, and Feng Wang*
JACS, 2022, DOI:10.1021/jacs.2c07410
Herein, we demonstrate that hydrogen bonding on the catalyst surface and in the bulk solution can inhibit oxidation and reverse reaction of α-hydroxyethyl radicals (αHRs) in photocatalytic dehydrocoupling of ethanol over Au/CdS. Intentionally added water forms surface hydrogen bonds with adsorbed αHRs and strengthens the hydrogen bonding between αHRs and ethanol while maintaining the flexibility of radicals in solution, thereby allowing for αHRs’ desorption from the Au/CdS surface and their stabilization by a solvent. The coupling rate of αHR increases by 2.4-fold, and the selectivity of the target product, 2,3-butanediol (BDO), increases from 37 to 57%. This work manifests that nonchemical bonding interactions can steer the reaction paths of radicals for selective photocatalysis.
Ying Ji, Huifang Liu, Feng Wang*, Xinwen Guo*
Catal. Today, 2022, DOI: 10.1016/j.cattod.2022.09.001
It is a green and environment-friendly strategy to use biomass to assist the synthesis of catalysts and use the prepared catalysts for biomass utilization. In this study, aluminum-rich silicon-phosphorus-aluminum nanosheet (Al-SPAN) was synthesized with biomass amino acids as additives for catalytic transfer hydrogenation of ethyl levulinate to γ-valerolactone. Compared with commercial Al2O3, Al-SPAN showed greatly improved catalytic performance for the reaction. The conversion of ethyl levulinate was increased by 47 % and the yield of γ-valerolactone was increased by 52 %. The effects of different alcohol on the reaction properties were investigated, with isopropanol used as a safe and efficient hydrogen source... ...
Lin Yuan, Yancheng Hu, Xin Guo, Guangyi Li, Aiqin Wang, Yu Cong, Feng Wang*, Tao Zhang*, and Ning Li*
Chem Catalysis, 2, 2302-2311
Sorbate and benzoate are the two most important preservatives used in our daily life. In industry, they are prepared from non-renewable petroleum resources. To meet sustainable development, herein, alternative routes are established with biobased malonate, crotonaldehyde, and acrolein as the feedstocks. The condensation of malonate and crotonaldehyde over the DABCO catalyst produces sorbate in a 75% yield. Acrolein is compatible with this process as well, followed by the Diels-Alder reaction and decarbonylation/dehydrogenation over Pd/C to afford benzoate in a 73% overall yield. Life-cycle assessment implies that our route has promising potential in reducing our carbon footprint. Furthermore, this work provides an interesting avenue for the synthesis of monomers with biobased furfural derivatives.
Shichao Zhang, Hang Dong, An Lin, Chaofeng Zhang, Hong Du, Junju Mu*, Jianyu Han, Jian Zhang, and Feng Wang*
ACS Sustainable Chem. Eng., 2022, DOI:10.1021/acssuschemeng.2c04492
In this work, machine learning (ML) was employed to explore how the CO2 adsorption performance of amine-functionalized adsorbents is correlated with five factors: amine loading, amine type, pore volume, pore size, and specific surface area. We found that amine loading contributed the most to the effect of CO2 adsorption capacity, followed by pore volume. Pore size was the most important factor affecting amine efficiency, while the cycle stability of the adsorbent was basically related to the amine type, and the interaction effect between the influencing factors was explored by ML. In addition, the CO2 adsorption capacities of TEPA/KXY and PEI/KYX adsorbents were predicted by ML, and the results of ML prediction were consistent with our experimental results... ...
Meijiang Liu, Huifang Liu, Ning Li, Chaofeng Zhang, Jian Zhang, and Feng Wang*
Chemsuschem, 2022, DOI: 10.1002/cssc.202201068
Photocatalysis is a promising technology for conversion of the glycerol into formic acid, but photocatalytic oxidation of C–C bonds in glycerol exhibits poor selectivity towards formic acid because the photogenerated radicals (e.g., hydroxyl radicals) further oxidize formic acid to CO 2 . In this work, we revealed a synergy of photogenerated holes and superoxide radicals that achieved the selective oxidation of glycerol into formic acid over the TiO 2 catalyst. The charge separation of pristine TiO 2 was improved with the aid of oxygen, which resulted in efficient hole oxidation of the C–C bonds in glycerol to formic acid. Surface active species were controlled to prevent being converted to hydroxyl radicals on TiO 2 via controlling the oxygen and water contents, which solved the problem of formic acid peroxidation without sophisticated catalyst modifications. Mechanism studies suggested that glyceraldehyde and glycolaldehyde were the intermediates to generate formic acid... ...
Xueyuan Wang, Nengchao Luo, and Feng Wang*
Chin. J. Chem., 2022, 12, 1492-1505
Methane, the main component of natural gas and shale gas, can be converted to upgraded fuels, syngas and value-added chemicals. Due to the nonpolar character of methane and large bond dissociation energy of sp3 C—H bond, methane conversion requires strong oxidants or acids/bases for its activation. Photocatalysis capable of inducing highly oxidative surrogates enables methane C—H bond scission at room temperature, thereby avoiding side reactions and coke formation caused by high reaction temperature. The scission of methane C—H bond generates •CH3 that may undergo C—C bond coupling with carbon radicals, which is a versatile way to obtain C2+ chemicals... ...
Nengchao Luo, Wei Nie, Junju Mu, Shiyang Liu, Mingrun Li, Jian Zhang, Zhuyan Gao, Fengtao Fan, and Feng Wang*
ACS Catal., 2022, 12, DOI:10.1021/acscatal.1c06005
Photocatalytic production of chemicals and fuels with H2 evolution has raised broad interest due to the carbon emission-free feature. In this context, selective and fast scission of methanol C–H bonds for coproduction of H2 and ethylene glycol (EG) over metal–semiconductor composites remains to be achieved. Here, we demonstrate that indium nanoparticles (In NPs) with a low work function (<4.3 eV) increase the selectivity and activity of ZnIn2S4 for the scission of methanol C–H bonds. By accepting electrons from In NPs, ZnIn2S4 with enriched electrons tends to activate the C–H bond instead of the O–H bond. Besides, a relatively strong built-in field is formed between In NPs and the support, which facilitates photogenerated electron transfer to In NPs for H2 evolution. Consequently, 84% selectivity of EG is obtained, and the apparent quantum yields (365 nm) of EG and H2 reach 15.6 and 27.0%, respectively.
Ying Ji, Yi Zuo, Huifang Liu, Feng Wang*, and Xinwen Guo*
ChemsusChem, 2022, DOI: 10.1002/cssc.202200747
Self-assembled spheres of silico-phospho-aluminum nanosheets were synthesized with the addition of L-arginine and evaluated as catalysts for the valorization of furfural alcohol to fuel additives. Adding the amino acid, a bio-derived additive, contributed to higher external specific surface area and more active sites, featuring a simple, environment-friendly and feasible strategy to regulate the growth of nanosheets. Herein, in the reaction of furfural alcohol with ethanol, the performance of silico-phospho-aluminum nanosheets is significantly improved compared with typical silicon phosphorus aluminum catalyst SAPO-34. The yield of ethyl levulinate with the use of silico-phospho-aluminum nanosheets was 7.8 times higher than that of SAPO-34, and meanwhile the amount of undesirable byproduct diethyl ether was decreased by two orders of magnitude and negligibly produced compared with SAPO-34... ...
Zhe Zhang, Min Wang*, and Feng Wang*
Chem Catal., 2022, DOI:10.1016/j.checat.2022.04.001
The construction of heterojunction is effective for spatial separation of photo-induced carriers and is widely used in photocatalysis. However, owing to the poor lattice mismatch at the interface, the loose interface and the abundant of dangling bond generally constrain the interparticle migration of photocarriers. Here, we report the surface oxidative reconstruction of CdS to form CdO quantum dots (QDs)/CdS intimate heterojunction where CdS(200) and CdO(111) are tilted with a dihedral angel of 159° to form a semi-coherent interface, maximally reducing the interface dangling bonds. The semi-coherent interface and the quantum size of CdO-QDs efficiently promotes charge separation and migration to the surface, accelerating the photocatalytic bio-CO evolution. A wide range of biomass resources, even polysaccharides can be converted into CO.
Feng Wang* and Haodong Duan*
Chem Catal., 2022, 4, 644-646
Biomass is a sustainable carbon resource in nature with abundant functional groups and can be converted into chemicals and fuels, reducing carbon emissions and alleviating the energy crisis as a promising alternative to fossil fuels. However, the complex structure, abundant oxygen-containing functional groups, and robust C–C bonds of biomass make its transformation require harsh reaction conditions, which often lead to condensation side reactions, resulting in complex polymers and poor selectivity to desired products.
Haohong Duan* and Feng Wang*
Chem Catal., 2022, 4, 641-643
The ever-increasing consumption of finite fossil fuels (coal, crude oil, and natural gas) has caused rapidly growing carbon emissions, resulting in global warming and other environmental problems. Biomass is a promising substitute for traditional fossil fuels because of its Earth-abundant and carbon-neutral nature. Aside from the significant progress on thermal catalysis, the valorization of biomass ideally driven by renewable electricity (solar, wind, tide, etc.) has captured tremendous attention in the past decades. Other electrocatalysis benefits worth mentioning are the mild conditions (room temperature and ambient pressure) and that no external oxidants or reductants are required, so the use of toxic and environmentally unfriendly reagents can be avoided... ...
Hongman Sun, Yu Zhang, Chunfen Wang, Mark A. Isaacs, Ahmed I. Osman, Yehong Wang, David Rooney, Youhe Wang, Zifeng Yan, Christopher M.A. Parlett*, FengWang*, and Chunfei Wu*
Chem. Eng. J., 2022, 437, 135394:1-12
Integrated carbon capture and utilization (ICCU) presents an ideal solution to address anthropogenic carbon dioxide (CO2) emissions from industry and energy sectors, facilitating CO2 capture and subsequent utilization through conversion into high-value chemicals, as opposed to current release into the atmosphere. Herein, we report the synergistic coupling of porous CaO, as a sorbent for CO2 capture, and Ni doped CeO2 nanorods, as catalytic sites for CO2 reduction. It is found that ceria is shown to possess the capacity for CO2 utilization, however, critically it only results in the generation of CO due to the weak CO-ceria bonding. The addition of Ni active sites gives rise to CH4 being the predominant product, via the strong interaction between Ni species and CO, which facilitates further reduction... ...
Jianyu Han,Junju Mu, and Feng Wang
Metal Single Atom Catalysis[B], 2022, DOI: 10.1002/9783527830169.ch4Supported
Single-atom catalyst (SAC) is a recently emerging frontier of heterogeneous catalysts, representing human's ability to manipulate microscopic structures. It has exhibited outstanding catalytic performances in various reactions such as alkene hydrogenation, alcohol oxidation, and electrochemical oxygen reduction. The key advantages of SACs are maximizing the utilization rate of scarce elements and enabling accurate theoretical modeling. This chapter categorizes three kinds of single-atom alloys (SAAs), namely, diluted SAAs, single-atom doping alloy, and diatomic alloy. Additionally, their preparation, characterization, and application are summarized.
Kaiyi Su, Chaofeng Zhang*, Yehong Wang, Jian Zhang, Qiang Guo, Zhuyan Gao, and Feng Wang*
Chin. J. Catal., 2022, 43, 1894-1905
Although different NbOx units are present in Nb2O5-based catalysts, the correlations between these structures and activity remain unclear, which considerably hinders the further development of Nb2O5 photocatalysis. Herein, we utilized N-hydroxyphthalimide (NHPI) as the probe molecule to distinguish the role of different NbOx units in the activation of C-H bond under visible light irradiation. With the addition of NHPI, Nb2O5 catalysts with highly disordered NbO6 units exhibited higher activities than that with slightly disordered NbO6 units (419‒495 vs. 82 μmol·g-1·h-1) in photocatalytic selective oxidation of ethylbenzene. Revealed by Raman spectra, electron paramagnetic resonance spectra, and transmission-electron-microscopy images, highly disordered NbO6 units were confirmed to act as the active sites for the transfer of photogenerated electrons from NHPI, ...
Shichao Zhang, Wenbin Chen, Junju Mu*, Jianyu Han, Chaofeng Zhang, Zhuyan Gao, Jian Zhang, Yehong Wang, and Feng Wang*
Chem. Eng. J., 2022, 436, 135211:1-9
In this work, we propose a strategy that enhances the dispersion and stability of tetraethylene pentamine (TEPA) via anchoring TEPA with single site Ni(II) in the pore of the commercial mesoporous silica gel (SG). The microscopic morphology and dynamic behavior of TEPA molecules in the adsorbents preparation process were explored by molecular dynamics simulation, which proved that the dispersibility of anchored TEPA in the porous structure has been improved, resulting in enhanced mass transfer and increased kinetic adsorption rate. The anchored Ni-TEPA/SG adsorbents exhibit a 37.5% faster kinetic adsorption rate than TEPA/SG adsorbents at 30 wt% TEPA loading, and the time required to reach 90% of maximum adsorption capacity is shortened by 6 times......
Zili Wu, Qihua Yang, Yan Liu, Boyu Zhang, Rengui Li, Wangyin Wang, Jijie Wang, Kazunari Domen, Feng Wang*, and Fengtao Fan*
ACS Catal., 2022, 12, 3063–3082
Prof. Can Li is distinguished for his seminal achievements in fundamental and applied researches in catalysis, especially in advancing the characterization of catalysts and catalytic reactions related to solar energy conversion and fine chemical synthesis. The scope of his research is wide ranging, and he is leading some of the fields. This account highlights his major scientific achievements in advancing the fundamental sciences of characterizing catalysts and understanding the mechanisms of catalytic reactions by developing in situ spectroscopic techniques (e.g., infrared (IR), ultraviolet (UV), Raman, space- and time-resolved spectroscopies and photoelectric imaging), and applying the obtained knowledge in the rational design and synthesis of catalysts for practical applications in photocatalytic, electrocatalytic and photoelectrocatalytic water splitting and CO2 reduction, chiral synthesis in nanoreactors and ultradeep desulfurization of fuels, and fine chemical synthesis.
Xiaojun Shen, Chaofeng Zhang, Buxing Han, Feng Wang*
Chem. Soc. Rev., 2022, DOI: 10.1039/d1cs00908g
Plentiful aliphatic hydroxyl and methoxy groups exist in native lignin and offer a renewable alternative to H2, and can be hydrogen sources for the depolymerization and upgradation of lignin via the intramolecular catalytic transfer hydrogenation. The hydrogen source in situ generated from lignin is a type of green hydrogen, decreasing the carbon footprint. The purpose of this review is to provide a summary and perspective of lignin valorization via self-transfer hydrogenolysis, mainly focusing on a comprehensive understanding of the mechanism of catalytic self-transfer hydrogenolysis at the molecular level and developing highly effective catalytic systems. Moreover, some opportunities and challenges within this attractive field are given to discuss future research directions.
Qiang Guo, Yehong Wang, Jianyu Han, Jian Zhang, and Feng Wang*
ACS Catal., 2022, 12, 3286−3290
Herein, a promising approach to realize the ethylene carbonylation followed by C–C bond formation to produce 3-pentanone was developed by coupling with alcohol dehydrogenation–transfer–hydrogenation (DTH) reactions on a ceria-supported Rh catalyst. The interfacial Lewis acid–base pair site (Rhδ+–O–Ce3+–Ov), which is constituted by Lewis acidic Ce3+–Ov (oxygen vacancy) and basic interfacial oxygen of Rhδ+–O–Ce3+, dissociatively activates alcohol and its DTH reactions, which promotes the tandem reaction of ethylene carbonylation and C–C coupling to 3-pentanone. This route provides an alternative way to selectively synthesize higher ketones by one-step olefin carbonylation.
Yehong Wang, Jiaxu Liu, Zhitong Zhao, Qiang Guo, Qike Jiang, Ning He, and Feng Wang*
Appl. Catal. B-Environ., 2022, DOI:10.1016/j.apcatb.2022.121139
Sustainable technologies and efficient process design in chemical synthesis are in great demand for achieving a low-carbon society. Here, a sustainable approach for producing aromatics is designed via a biomass-derived carbon-negative route. A target aromatic yield of up to 50% was achieved using an industrial aqueous oxygenate mixture as the feedstocks. Such high performance is ascribed to the Zn modified ZSM-5 zeolites, which were proved to introduce synergistic catalysis involving Lewis acid sites and Brönsted acid sites, and were essential to aromatize these oxygenates efficiently. This approach provides a promising route for converting biomass-derived complex mixtures to valuable chemicals toward the carbon-neutral goal.
Zhipeng Huang, Nengchao Luo, Chaofeng Zhang, and Feng Wang*
Nat. Rev. Chem., 2022, DOI:10.1038/s41570-022-00359-9
Photocatalysis is an emerging approach for sustainable chemical production from renewable biomass under mild conditions. Active radicals are always generated as key intermediates, in which their high reactivity renders them versatile for various upgrading processes. However, controlling their reaction is a challenge, especially in highly functionalized biomass frameworks. In this Review, we summarize recent advanced photocatalytic systems for selective biomass valorization, with an emphasis on their distinct radical-mediated reaction patterns. The strategies for generating a specific radical intermediate and controlling its subsequent conversion towards desired chemicals are also highlighted, aiming to provide guidance for future studies. We believe that taking full advantage of the unique reactivity of radical intermediates would provide great opportunities to develop more efficient photocatalytic systems for biomass valorization.
Chaofeng Zhang*, Zhuyan Gao, Puning Ren, Jianmin Lu, Zhipeng Huang, Kaiyi Su, Shichao Zhang, Junju Mu, and Feng Wang*
Green Chem., 2022, DOI:10.1039/D1GC04058H
We herein report that the MoS2 with oxygen-implanting modification (O-MoS2) can work as a multifunctional catalyst to achieve the one-pot quinolines synthesis from basic nitroarenes and aliphatic alcohols. By overturning the catalysis cognition that O2 adsorption on MoSx can deactivate the MoS2-based catalysts to an efficient method for in-situ healing the MoOx structure in O-MoS2 and protecting the O-MoS2 catalyst by inhibiting unwanted MoOx elimination with extra H*, we innovatively introduce O2 in the quinoline synthesis. The robust O-MoS2 can be consecutively used ten times without regeneration and keep offering 69~75% yields of 2-methylquinoline from nitrobenzene and ethanol. Furthermore, different from the traditional transfer hydrogenation-condensation mechanism, an integrated oxidation-transfer hydrogenation-cyclization mechanism is proposed over the O-MoS2 catalyst.
Siqi Li, Zhipeng Huang, Huifang Liu, Meijiang Liu, Chaofeng Zhang* and Feng Wang
Dalton Trans., 51, 1553-1560
We herein present an efficient approach for the chemoselective synthesis of arylamines from nitroarenes and hydrazine over an iron-molybdenum sulfide catalyst ([FeMo]Sx). The heterogeneous hydrogen transfer reduction can be efficiently carried out at 30 °C and provides anilines with 95–99% selectivities. The in situ gas product analysis demonstrates that [FeMo]Sx can catalyze the decomposition of N2H4 to H* species, not H2. Combining with the kinetic analysis of the aniline generation rates from nitrobenzene and intermediates, the nitro group reduction to the nitroso group is confirmed to be the rate-determining step. The positive slope of Hammett's equation suggests that the critical intermediate in the rate-determining step is in the negative state, which suggests that the active H* should be in polar states (Hδ− and Hδ+). These findings will provide a novel route for the synthesis of substituted anilines and broaden the application of MoSx catalysts under mild conditions.
Anon Bunrit, Teera Butburee, Meijiang Liu, Zhipeng Huang, Keerati Meeporn, Chaiyasit Phawa, Jian Zhang, Sanchai Kuboon, Huifang Liu, Kajornsak Faungnawakij*, and Feng Wang*
ACS Catal., 2022, 12, 1677-1685
Herein, we developed photo–thermo-dual catalytic strategies for the production of γ-valerolactone (GVL) from levulinic acid (LA) and its ester using platinum-loaded TiO2 as a dual-functional catalyst. Both catalytic systems were evaluated under mild reaction conditions. In the photocatalysis system, a base plays crucial roles in the conversion of LA and EL to GVL. The control experiments reveal that plausible mechanistic pathways of both systems proceed via the hydrogenation of the ketone group of LA to the corresponding alcohol as a major intermediate followed by a subsequent cyclization step to GVL. This dual-functional catalyst provides alternative strategies for the conversion of LA and its ester into GVL, which could pave the way for biomass utilization in a more effective and practical manner.
Kaiyi Su, Huifang Liu, Chaofeng Zhang, and Feng Wang*
Chin. J. Catal., 2022, 43, 589-594
As a great threat to all livings on earth, waste artificial plastics now are everywhere, from oceans to our cells. The world cannot withstand the growing waste plastic in million tonnes every year, which has already caused environmental pollution and economic losses. Besides the efforts for preparing novel plastics with the self-decomposition ability, the world needs methods to clear away these waste plastics leftover from history or recycle well this organic carbon resource. Photocatalysis is a potential solution for the conversion of waste plastics under mild conditions. In this perspective, we highlight the effect of photocatalytic approaches toward the generation of low carbon number organic products (Cn products, n ≤ 8) from waste plastics, which can proceed under an inert or aerobic atmosphere. Notably, critical analysis of the carbon source in products is necessary to reveal the active species for the C–X bonds (X = C, N, and O) cleavage of plastics... ...
Yehong Wang, Zhixin Zhang, Lijun Lei, Wen Liu, Shuyan Du, Xiangxue Zhu, Xiujie Li*, and Feng Wang*
ACS Sustainable Chem. Eng., 2021, 9, 17301-17309
In this work, we developed a strategy to realize selective C–H/C–C bond cleavage of propane with CO2 as the oxidant by controlling the defect concentrations of ceria supports over FeNi/ceria catalysts. Two types of ceria with distinct defect concentrations were prepared successfully. The propane conversion achieved 25.2% with 49% propylene selectivity via C–H bond cleavage over the defect-rich ceria-supported FeNi catalyst at 550 °C. In contrast, CO is generated via C–C bond cleavage with 95% selectivity when defect-deficient ceria was used as the support. The essential role of defects in the ceria support was investigated carefully by UV–Raman, X-ray photoelectron spectroscopy, and H2-temperature-programmed reduction. This work provides a method for defect tuning of ceria-based catalysts and realizes the selective conversion of CO2 and alkanes to value-added chemicals.
Lin Yuan#, Yancheng Hu#, Zhitong Zhao#, Guangyi Li, Aiqin Wang, Yu Cong, Feng Wang*,Tao Zhang*, and Ning Li*
Angew. Chem. Int. Ed., 2021, 61, e202113471:1-5
PCTA is an important copolyester that has been widely used in our daily necessities. Currently, its monomers are industrially produced from petroleum-derived xylene. To reduce the reliance on fossil energy, we herein disclose an alternative route to access PCTA monomer (terephthalate/isophthalate=2.4/1) in 61 % overall yield using plant-based acrylate and acetaldehyde as the feedstocks. The process includes Morita–Baylis–Hillman (MBH) reaction of acetaldehyde with acrylate, subsequent one-step dehydration/Diels–Alder reaction with acrylate over H2SO4/SiO2 catalyst, and final Pd/C-catalyzed dehydrogenation. Besides, when varying the final step to hydrogenation, another important monomer UNOXOL™ diol (1,4-trans/1,4-cis/1,3-trans/1,3-cis=5.2/2/2.5/1) can be produced in 67 % overall yield.
Tingting Hou#, Zhuyan Gao#, Jian Zhang, Nengchao Luo, and Feng Wang*
Trans. Tianjin Univ., 2021, 27, 331–337
Herein, we constructed N-doped TiO2 nanotubes (N-TNTs) that exhibited remarkable activity and selectivity for toluene oxidation under visible light, delivering the conversion of toluene and selectivity of benzaldehyde of 32% and > 99%, respectively. Further mechanistic studies demonstrated that the incorporation of nitrogen induced the generation of N-doping level above the O 2p valance band, directly contributing to the visible-light response of TiO2. Furthermore, hydroxyl radicals generated by photogenerated holes at the orbit of O 2p were found to be unselective for the oxidation of toluene, affording both benzaldehyde and benzoic acid. The incorporation of nitrogen was able to inhibit the generation of hydroxyl radicals, terminating the formation of benzoic acid.
Hongru Zhou, Min Wang*, and Feng Wang*
Chem., 2021, 8, 465-479
Carbon monoxide (CO) is a large-scale feedstock and fuel, which is industrially produced from steam reforming of coal and methane at high temperatures. Photocatalytic CO production from biomass at room temperature is a promising route but still shows low activity. Targeting this problem, we propose an oxygen-controlled photo-reforming method to promote CO evolution from biopolyols and sugars. Appropriate O2 content turns the reaction into thermodynamically favorable, thus accelerating the CO generation rate. A core-shell structure Z-scheme CdS@g-C3N4 was prepared as the photocatalyst. The particular catalyst structure facilitates the adsorption and activation of dioxygen, thus accelerating the CO evolution.
Kaiyi Su, Huifang Liu, Chaofeng Zhang, and Feng Wang*
Chin. J. Catal., 2021, 43, 589-594
As a great threat to all livings on earth, waste artificial plastics now are everywhere, from oceans to our cells. The world cannot withstand the growing waste plastic in million tonnes every year, which has already caused environmental pollution and economic losses. Besides the efforts for preparing novel plastics with the self-decomposition ability, the world needs methods to clear away these waste plastics leftover from history or recycle well this organic carbon resource. Photocatalysis is a potential solution for the conversion of waste plastics under mild conditions. In this perspective, we highlight the effect of photocatalytic approaches toward the generation of low carbon number organic products (Cn products, n ≤ 8) from waste plastics, which can proceed under an inert or aerobic atmosphere. Notably, critical analysis of the carbon source in products is necessary to reveal the active species for the C–X bonds (X = C, N, and O) cleavage of plastics... ...
Dongxia Jiao, Yehong Wang*, Zhixin Zhang, Jian Zhang, Lijun Lei, and Feng Wang*
ChemCatChem, 2021, 13, 4159-4163
Formamide is an important solvent and synthetic intermediate. Herein, we designed a hydroxyapatite (HAP)-stabilized, positively charged Ru-based catalysts which can efficiently catalyze the formylation reaction of amines with CO for the synthesis of formamide. The Ru-HAP showed excellent catalytic performance in N,N-Dimethylformamide (DMF) synthesis, with about 75% DMA (dimethylamine) conversion and >99% DMF selectivity at 300 h of continuous reaction. The combination of characterization results and control experiments showed that positively charged Ru species, including hydrated RuO x and Ru 3+ species, were catalytically active. In particular, the surface RuO x species were more active than the Ru 3+ species located within the HAP framework.
Hongru Zhou, Min Wang*, and Feng Wang*
Joule, 2021, 5, 3031-3044
Biomethane is a clean energy and a key platform chemical for modern chemical industries. The conversion of biomass, especially the most abundant lignocellulose, into biomethane is challenging and shows low selectivity either in chemical or biological processes. Herein, we report the direct methanation of biomass at temperatures below 200°C with >95% selectivity using interfacial oxygen-vacancy (VO)-mediated catalysis over Ru/TiO2. The biomass feedstock is oxidized by TiO2 to form CO2 and VO, and CO2 is then in situ reduced on Ru sites to CH4, restoring the oxygen to VO simultaneously. Various biomass resources were converted into methane with 82%–99% yields. Even lowering the temperature to 120°C, about 0.24 mmol g−1 h−1 of CH4 with >99% selectivity was steadily produced from 50 wt % aqueous glycerol for 432 h. In situ X-ray photoelectron spectroscopy, infrared spectrometry, and DFT calculation confirm the VO-mediated catalysis process over Ru/TiO2.
Kaiyi Su, Yehong Wang, Chaofeng Zhang, Zhuyan Gao, Jianyu Han, and Feng Wang*
Appl. Catal. B-Environ., 2021, 298, 120554
Herein, we reported the tuning of dominant products in the photocatalytic hydrogen transfer reaction over Pt/Nb2O5 photocatalysts, using a support-induced modification strategy. In the photocatalytic conversion of phenylacetylene with ethanol as a probe reaction, the dominant product was styrene over Pt/2D Nb2O5 nanoplates; in contrast, H2 was the main product over the Pt/bulk Nb2O5. Compared to the metallic Pt species over bulk Nb2O5, the positively charged Pt (Ptδ+) species over 2D Nb2O5 nanoplates contributed to the reduction of phenylacetylene, which was revealed by CO adsorbed Fourier transform infrared spectra.
Xiubing Huang*, Kaiyue Zhang, Baoxiang Peng, Ge Wang*, Martin Muhler*, and Feng Wang*
ACS Catal., 2021, 11, 9618-9678
Value-added chemicals, fuels, and pharmaceuticals synthesized by organic transformation from raw materials via catalytic techniques have attracted enormous attention in the past few decades. Heterogeneous catalysts with high stability, long cycling life, good environmental-friendliness, and economic efficiency are greatly desired to accomplish the catalytic organic transformations. With the advantages of reversible Ce3+/Ce4+ redox pairs, tailorable oxygen vacancies, and surface acid–base properties, ceria-based catalysts have been actively investigated in the fields of catalytic organic synthesis. In this Review, we summarize the fundamentals and latest applications of ceria-based heterogeneous catalysts for organic transformations via thermocatalytic and photocatalytic routes.
Zhe Zhang, Min Wang*, Hongru Zhou, and Feng Wang*
J. Am. Chem. Soc., 2021, 143, 6533-6541
Photocatalytic biomass conversion represents an ideal way of generating syngas because of the sustainable use of biomass carbon and solar energy. However, the lack of efficient electron–proton transfer limits its efficiency. We here report an unprecedented method to simultaneously increase both the electron and proton transfer by creating surface sulfate ions on the CdS catalyst ([SO4]/CdS). Surface sulfate ion [SO4] is bifunctional, serving as the proton acceptor to promote proton transfer, and increasing the oxidation potential of the valence band to enhance electron transfer...
Zhuyan Gao, Nengchao Luo*, Zhipeng Huang, Stuart H. Taylor, and Feng Wang*
ACS Sustain. Chem. Eng., 2021, 9, 6188-6202
Low-carbon number alcohols (LCNAs) are important platform molecules that can be derived from many resources, such as coal, oil, natural gas, biomass, and CO2, creating a route to value-added chemicals and fuels. Semiconductor photocatalysis provides a novel method for converting LCNAs into a variety of downstream products. Photocatalysis is initiated by light-excited charge carriers that are highly oxidative and reductive. The polarity and bond dissociation energy (BDE) of Cα–H bonds are small for alcohols, so it can be homolytically dissociated by the participation of photogenerated holes. Consequently, photocatalytic LCNA conversion overcomes the challenge of Cα–H bond activation in thermocatalysis. Apart from carbon radicals generated from Cα–H bond cleavage, many other radicals are formed during photocatalysis, which are active and have multiple conversion pathways, resulting in complex product distributions...
Zhixin Zhang*, Yehong Wang, Chaofeng Zhang, Feng Wang*
Chem. Ind.& Eng. Prog., 2021, 40, 2016-2033
Acrylic acid (AA) is an important industrial chemical intermediate and polymer monomer, which is in great demand. The rich coal resources and renewable biomass resources in China provide a solid material guarantee for the coal-based and biomass-based synthesis routes of acrylic acid. The two main routes were reviewed, including the synthesis routes of acrylic acid from coal-based chemicals, such as CO, low carbon alcohols (methanol and ethanol), formaldehyde, acetic acid, ethylene, and so on, and the synthesis routes of acrylic acid using glycerol, 3-hydroxypropionic acid, lactic acid, fumaric acid, and muconic acid. These routes are compared to provide a reference for the route selection...
Jinghua An, Zhuyan Gao, Yehong Wang, Zhixin Zhang, Jian Zhang, Lu Li, Bo Tang, Feng Wang*
Green Chem., 2021, 23, 2722-2728
Synthesizing amines via the hydroaminomethylation (HAM) reaction of olefins, a multicomponent reaction, has been regarded as one of the most attractive methods compared with the traditional methods considering the atom economy and environmental friendliness. However, the use of homogeneous catalysts, complex ligands containing diphosphine or nitrogen, and base or acid additives has severely hampered the utilization of these methods. Herein, an efficient heterogeneous Ru/TiO2-catalyzed HAM reaction of olefins is developed without any additives. Various amines, including secondary and tertiary amines, can be successfully obtained from olefins including aromatic and aliphatic olefins. Systematic studies demonstrate the lower electron density of Ruδ+ and the higher number of acid sites of Ru/TiO2, leading to the high HAM reaction activity of olefins. Most importantly, nitrobenzene derivatives can also be transformed to the corresponding products over Ru/TiO2 in excellent yields.
Chaofeng Zhang, Feng Wang*
Elsevier, 2021, 77, 175-218
In this chapter, focusing on lignin catalytic depolymerization to aromatic chemicals, we herein first provide our understanding about the scientific question and strategic foundation process in lignin depolymerization, and then clarify them by mainly presenting our recent studies. Firstly, we introduce our research on direct protolignin depolymerization via a fragmentation–hydrogenolysis process in alcohol solvents. Then, focusing on the catalytic cleavage of lignin C-C and C-O bonds, we shed light on a recapitulative adjacent functional group modification (AFGM) strategy for the conversion of lignin models and apply the established methods in the real lignin conversion via a bottom-up research approach......
Mahdi M. Abu-Omar, Katalin Barta, Gregg T. Beckham*, Jeremy S. Luterbacher*, John Ralph*, Roberto Rinaldi, Yuriy Román-Leshkov, Joseph S. M. Samec*, Bert F. Sels, Feng Wang.
Energy Environ. Sci., 2021, 14, 262-292
We present herein a set of guidelines for analysing critical data from lignin-first approaches, including feedstock analysis and process parameters, with the ambition of uniting the lignin-first research community around a common set of reportable metrics. These guidelines comprise standards and best practices or minimum requirements for feedstock analysis, stressing reporting of the fractionation efficiency, product yields, solvent mass balances, catalyst efficiency, and the requirements for additional reagents such as reducing, oxidising, or capping agents. Our goal is to establish best practices for the research community at large primarily to enable direct comparisons between studies from different laboratories. The use of these guidelines will be helpful for the newcomers to this field and pivotal for further progress in this exciting research area.
Kaiyi Su, Huifang Liu, Zhuyan Gao, Paolo Fornasiero*, Feng Wang*
Adv. Sci., 2021, 8, 2003156
Niobium pentoxide (Nb2O5), a typically nontoxic metal oxide, is eco‐friendly and exhibits strong oxidation ability, and has attracted considerable attention from researchers. Furthermore, unique Lewis acid sites (LASs) and Brønsted acid sites (BASs) are observed on Nb2O5 prepared by different methods. Herein, the recent advances in the synthesis and application of Nb2O5‐based photocatalysts, including the pure Nb2O5, doped Nb2O5, metal species supported on Nb2O5, and other composited Nb2O5 catalysts, are summarized. An overview is provided for the role of size and crystalline phase, unsaturated Nb sites and oxygen vacancies, LASs and BASs, dopants and surface metal species, and heterojunction structure on the Nb2O5‐based catalysts in photocatalysis. Finally, the challenges are also presented, which are possibly overcome by integrating the synthetic methodology, developing novel photoelectric characterization techniques, and a profound understanding of the local structure of Nb2O5.
Zhitong Zhao, Jingyang Jiang, Mingyuan Zheng, Feng Wang*
Chem. Eng. J., 2021, 411, 128516
To achieve the economic benefits of bio-EG, research strategies, such as raising the product yield, changing hydrogen sources, increasing feedstock collection efficiency, and lowing water consumption were explored and proved to be effective measures. In addition, a carbon tax of 184 and 598 CNY·t-1 CO2eq are the breakeven points to reach economic benefits of bio-EG compared to petro-EG and coal-EG, respectively. This work aims at conducting a comprehensive evaluation of bio-EG to promote its practical application, and also shedding light on bright prospects and general approaches to develop lignocellulosic biochemicals.
Hongman Sun, Yehong Wang, Shaojun Xu, Ahmed I. Osman, Gavin Stenning, Jianyu Han, Shuzhuang Sun, David Rooney, Paul T. Williams*, Feng Wang*, Chunfei Wu*
Fuel, 2021, 286, 119308:1-8
The distance between catalytic sites (Ni) and sorbents (CaO) on the performance of integrated CO2 capture and utilization (ICCU) process is crucial important because the sorbents demonstrate a dramatic volume increase during carbonation reaction (1st stage of ICCU) and sequentially cover the catalytic sites and retard the CO2 conversion (2nd stage of ICCU). Herein, we synthesized various Ni/CaO-based dual functional materials (DFMs) with different distances between active sites and sorbents to provide different volume spaces for the growth of CaCO3 during the carbonation reaction. It is found that both 1%NiCaO and 10%NiCaO synthesized by a one-pot method exhibited a low CO2 conversion (38% and 45%, respectively) and CH4 selectivity (58% and 69%, respectively) as the distance between catalytic sites and sorbents was so close that the Ni active sites were covered by the formed CaCO3 during carbonation reaction......
Zhitong Zhao, Jingyang Jiang*, Feng Wang*
J. Energy Chem., 2021, 56, 193-202
A comprehensive economic analysis of twenty light olefin production pathways has been performed, covering current and promising processes from fossil (petroleum, coal and natural gas) and renewable resources (biomass and CO2). Taking steam cracking of naphtha as the benchmark, this study gives an economic perspective and points out the bottleneck in different olefin production pathways. The assessment indicates that nearly all renewable pathways are economically unattractive currently and the raw material cost accounts for dominant contribution in most pathways, especially in the oil-, natural gas- and CO2-derived pathways. More details......
Huifang Liu, Jianyu Han, Qitian Huang, Hongwei Shen, Lijun Lei, Zhipeng Huang, Zhixin Zhang, Zongbao K. Zhao*, Feng Wang*
Ind. Eng. Chem. Res., 2020, 59, 17440-17450
Catalytic hydrotreating of renewable oils is a promising way to get diesel alkanes, with the use of microbial lipids further facilitating scalable production of green diesel. The core issue of triglyceride hydrodeoxygenation (HDO) research is still to develop efficient catalysts under mild reaction conditions. Herein, we demonstrate that the heteropolyacid (HPA)-modified SiO2 supported Pd catalysts showed high activity for the HDO reaction of methyl stearate and soybean oil to diesel alkanes (C15∼C18, >90 wt % at 200 °C). Characterizations show that the Brønsted acid sites introduced by grafting heteropolyacid on SiO2 and metal sites of small Pd particles contribute to the high HDO activity of this bifunctional catalyst. Additionally, lipids produced by Rhodosporidium toruloides Y4 from glucose or corn stover were also transformed to about 75 wt % of diesel-range alkane products......
Xuejiao Wu, Nengchao Luo, Shunji Xie*, Haikun Zhang, Qinghong Zhang, Feng Wang*, Ye Wang*
Chem. Soc. Rev., 2020, 49, 6198-6223
As the largest renewable carbon resource, lignocellulosic biomass has great potential to replace fossil resources for the production of high-value chemicals, in particular organic oxygenates. Catalytic transformations of lignocellulosic biomass using solar energy have attracted much recent attention, because of unique reactive species and reaction patterns induced by photo-excited charge carriers or photo-generated reactive species as well as the mild reaction conditions, which may enable the precise cleavage of target chemical bonds or selective functionalisation of specific functional groups with other functional groups kept intact. Here, we present a critical review on recent advances in the photocatalytic transformation of lignocellulosic biomass with an emphasis on photocatalytic cleavage of C–O and C–C bonds in major components of lignocellulosic biomass, including polysaccharides and lignin, and the photocatalytic valorisation of some key platform molecules......
Lijun Lei, Yehong Wang, Zhixin Zhang, Jinghua An, Feng Wang*
ACS Catal., 2020, 10, 8788-8814
In the past two decades, on account of the energy and environmental crisis brought by the decline in fossil resources, price volatility, and climate change, the high-value utilization of biomass feedstocks has gradually attracted widespread attention. The reversible Ce3+/Ce4+ redox pairs and the existence of oxygen vacancies improve its redox ability and thus catalytic activity. Besides, the acid-base properties enable its use in acid-base catalytic reactions. The strength or concentration of acid-base sites is tailorable. The water-tolerance character is unique and thus can be employed in the conversion of dilute aqueous biomass solutions. In this perspective, we summarize the latest research progress in the high-value utilization of biomass feedstocks, including biomass raw materials, platform molecules originated from biomass as well as its derivatives and downstream chemicals over pure CeO2, doped-CeO2 and CeO2 supported metal catalysts.
Hongji Li‡, Meijiang Liu‡, Huifang Liu, Nengchao Luo, Chaofeng Zhang, Feng Wang*
ChemSusChem, 2020, 13, 4660-4665
Introducing amines/ammonia into lignin cracking will allow novel bond cleavage pathways. Herein, a method of amines/ammonia-mediated bond cleavage in oxidized lignin β-O-4 models was studied using a copper catalyst at room temp., demonstrating the effect of the amine source on the selectivity of products. For primary and secondary aliph. amines, lignin ketone models underwent oxidative Cα-Cβ bond cleavage and Cα-N bond formation to generate arom. amides. For ammonia, the competition between oxygen and ammonia detd. the selectivity between Cα-N and Cβ-N bond formation, generating amides and α-keto amides, resp. For tertiary amines, the lignin models underwent oxidative Cα-Cβ bond cleavage to benzoic acids. Control expts. indicated that amines act as nucleophiles attacking at the Cα or Cβ position of the oxidized β-O-4 linkage to be cleaved. This study represents a novel example that the breakage of oxidized lignin model can be regulated by amines with a copper catalyst.
Hongji Li, Anon Bunrit, Ning Li, Feng Wang*
Chem. Soc. Rev., 2020, 49, 3748-3763
Lignin, the most abundant aromatic polymer in nature, enables sustainable supply of miscellaneous aromatics as green fuels and chemicals. Obtaining the value-added aromatics from lignin, though subjected to enormous research efforts, mainly relies on depolymerization induced by activated hydrogen species or oxygen species, delivering hydrocarbons and oxygenates. The future bio-refinery demands a broad spectrum of fine chemicals, especially those containing elements other than C, H and O. Heteroatom-containing compounds have emerged as powerful reagents to participate in the bond cleavage in lignin; meanwhile, the obtained heteroatom-containing aromatics, which could be used as dye precursors, pharmaceutical precursors, hydrogen storage materials, etc., extend the application of lignin-derived products...
Hongji Li, Zhuyan Gao, Lijun Lei, Huifang Liu, Jianyu Han, Feng Hong, Nengchao Luo, Feng Wang*
Green Chem., 2020, 22, 3802-3808
A mild method of photocatalytic deoxygenation of aromatic ketones to alkyl arenes was developed, which utilized alcohols as green hydrogen donors. No hydrogen evolution during this transformation suggested a mechanism of direct hydrogen transfer from alcohols. Control experiments with additives indicated the role of acid in transfer hydrogenolysis, and catalyst characterization confirmed a larger number of Lewis acidic sites on the optimal Pd/TiO2 photocatalyst. Hence, a combination of hydrogen transfer sites and acidic sites may be responsible for efficient deoxygenation without additives. The photocatalyst showed reusability and achieved selective reduction in a variety of aromatic ketones.
Jinghua An, Yehong Wang, Zhixin Zhang, Jian Zhang, Feng Wang*
Chin. J. Catal., 2020, 41(6), 963-969
Hydroalkoxycarbonylation of olefins has been considered to be one of the most attractive methods to synthesize esters. Controlling the regioselectivities of linear esters (L) and branched esters (B) is a challenging project for researchers working in this reaction. Although most of the attention has been paid to control the regioselectivity through ligand design in homogeneous catalytic sy...
Min Wang, Meijiang Liu, Jianmin Lu, Feng Wang*
Nat. Commun., 2020, 11, 1083
We report the conversion of biomass-derived polyols and sugars into methanol and syngas (CO+H2) via UV light irradiation under room temperature, and the bio-syngas can be further used for the synthesis of methanol. The cellulose and even raw wood sawdust could be converted into methanol or syngas after hydrogenolysis or hydrolysis pretreatment. We find Cu dispersed on titanium oxide nanorod (TNR) rich in defects is effective for the selective C−C bond cleavage to methanol. Methanol is obtained from glycerol with a co-production of H2. A syngas with CO selectivity up to 90% in the gas phase is obtained via controlling the energy band structure of Cu/TNR.
Zhipeng Huang‡, Zhitong Zhao‡, Chaofeng Zhang, Jianmin Lu, Huifang Liu, Nengchao Luo, Jian Zhang, Feng Wang*
Nat. Catal., 2020, 3, 170-178
Here we demonstrate that photogenerated radicals can be rapidly terminated by surface hydrogen species during photocatalytic decarboxylation of fatty acids on a hydrogen-rich surface that is constructed by the interactions between H2 and Pt/TiO2 catalyst, thereby greatly inhibiting oligomerization; Cn–1 alkanes can therefore be obtained from bio-derived C12–C18 fatty acids in high yields (≥90%) under mild conditions (30 °C, H2 pressure ≤0.2 MPa) and 365 nm light-emitting dode irradiation. Industrial low-value fatty acid mixtures (namely, soybean and tall oil fatty acids) can be transformed into alkane products in high yields (up to 95%). Our research introduces an efficient biomass-upgrading approach that is enabled by subtle control of the radical intermediate conversion on a heterogeneous surface.
Kaiyi Su, Huifang Liu, Bin Zeng, Zhixin Zhang, Nengchao Luo, Zhipeng Huang, Zhuyan Gao, Feng Wang*
ACS Catal., 2020, 10(2), 1324-1333
Photocatalytic selective oxidation of hydrocarbons to oxygenated chemicals greatly relies on catalytic materials that show high efficiency of photogenerated holes and electrons separation and visible light absorption capacity. We, herein, report one facile calcination approach with ammonium chloride and melamine as the template to synthesize nitrogen-modified Nb2O5 nanomeshes material (Nb2O5-N), which exhibits a 37-fold reaction rate larger than its commercial counterpart in photocatalytic oxidation of toluene into benzaldehyde under visible light irradiation. The reactivity is ascribed to an extended absorption spectrum within 700 nm by nitrogen modification. In addition, photocurrent response results suggest that a relaxation effect induced by nanomesh structure is beneficial for the separation of charge carriers for enhanced reactivity.
Nengchao Luo, Tingting Hou, Shiyang Liu, Bin Zeng, Jianmin Lu, Jian Zhang, Hongji Li, Feng Wang*
ACS Catal., 2020, 10(1), 762-769
Photocatalytic H2 evolution from organic feedstocks with simultaneous utilization of photogenerated holes achieves solar energy storage and coproduces value-added chemicals. Here we show visible-light H2 production from benzyl alcohol (BAL) with controllable generation of deoxybenzoin (DOB) or benzoin (BZ) through tandem redox reactions. Particularly, DOB synthesis circumvents the use of expensive feedstocks and environmentally unfriendly catalysts that are required previously. Under the irradiation of blue LEDs, the key of steering the major product to DOB rather than BZ is to decrease the conduction band bottom potentials of the ZnIn sulfide catalysts by increasing the Zn/In ratio, which results in the dehydration of intermediate hydrobenzoin (HB) to DOB proceeding in a redox-neutral mechanism and consuming an electron–hole pair. As a proof of concept, this method is used to synthesize DOB derivatives in gram scale.
Chaofeng Zhang, Feng Wang*
Acc. Chem. Res., 2020, 53(2), 470-484
We present our recent studies on lignin's catalytic conversion to aromatic chemicals. First, we introduce our research on protolignin depolymerization via a fragmentation–hydrogenolysis process in alcohol solvents. Then, focusing on the catalytic cleavage of lignin C–C and C–O bonds, we shed light on a recapitulative adjacent functional group modification (AFGM) strategy for the conversion of lignin models. AFGM strategy begins with the adjacent functional group modification of the target C–C or C–O bond to directly decrease the bond dissociation enthalpy (BDE) of targeted bonds or generate new substrate sites to introduce the cleavage reagent for further conversion. Subsequently, on the basis of these two concepts from AFGM, we summarize our strategies on lignin depolymerization, which highlight the effects of lignin structure, catalyst character, and reaction conditions on the efficiency of strategies.
Huifang Liu, Hongji Li, Nengchao Luo, Feng Wang*
ACS Catal., 2020, 10(1), 632-643
Using vanadium catalysts under visible light, we selectively cleave the C–C bonds in β-1 and β-O-4 interlinkages occluded in lignin models and extracts by an oxidative protocol. Visible light irradiation triggered single electron transfer between the substrate and the catalyst, which further induced the selective Cα–Cβ bond cleavage and generated the final aromatic products through radical intermediates. Using this photocatalytic chemistry, the reactivity of lignin models and the selectivity of Cα–Cβ bond cleavage were significantly improved. More importantly, this protocol affords aromatic monomers through the fragmentation of organosolv lignins even at room temperature, indicating the potential of photocatalytic C–C bond cleavage of lignin linkages under ambient conditions.
Tingting Hou, Nengchao Luo, Yi-Tao Cui, Jianmin Lu, Lei Li, Katherine E MacArthur, Marc Heggen, Ruotian Chen, Fengtao Fan, Wenming Tian, Shengye Jin, Feng Wang*
Appl. Catal. B-Environ., 2019, 245, 262-270
Engineering the electronic properties of heterogeneous catalysts is an important strategy to enhance their activity towards CO2 reduction. Herein, we prepared partially sulfurized cerium oxide (CeOx-S) nanoclusterswith the size less than 2 nm on the surface of ZnIn2S4 layers. Surface electronic properties of CeOx-S nanoclusters are facilely modulated by cerium coordination to sulfur, inducing ...
Hongji Li‡, Elena Subbotina‡, Anon Bunrit, Feng Wang*, Joseph S. M. Samec*
Chem. Sci., 2019, 10, 3681-3686
The idea of using biaryl structures to generate synthetic building blocks such as spirolactones is attractive because biaryl structures are abundant in biomass waste streams. However, the inertness of aromatic rings of biaryls makes it challenging to transform them into functionalized structures. In this work, we developed photoinduced dearomatization of nonphenolic biaryl compounds to generate...
Jianyu Han, Jianmin Lu, Min Wang, Yehong Wang, Feng Wang*
Chin. J. Chem., 2019, 37(9), 977-988
There have been remarkable progresses in manipulating heterogeneous catalysts' nanostructures in the past decade. The concept of single atom alloy (SAA) was firstly proposed in 2012 when researchers successfully stabilized single Pd atoms on the Cu(111) surface. However, earlier work in 2009, which focused on replacing one Au atom with a Pd atom in thiolate protected Au25 nanoclusters, cou...
Min Wang, Feng Wang*
Adv. Mater., 2019, 1901866
Lignin is an aromatic polymer, which is the biggest and most sustainable reservoir for aromatics. The selective conversion of lignin polymers into aryl monomers is a promising route to provide aromatics, but it is also a challenging task. Compared to cellulose, lignin remains the most poorly utilized biopolymer due to its complex structure. Although harsh conditions can degrade lignin, the...
Kimberly N. Heck, Yehong Wang, Gang Wu, Feng Wang, Ah-Lim Tsai, David T. Adamsond, Michael S. Wong*
RSC Adv., 2019, 9, 27042-27049
1,4-dioxane, commonly used as a solvent stabilizer and industrial solvent, is an environmental contaminant and probable carcinogen. In this study, we explored the concept of using metal oxides to activate H2O2 catalytically at neutral pH in the dark for 1,4-dioxane degradation. Based on batch kinetics measurements, materials that displayed the most suitable characteristics (high 1,4-dioxane d...
Jian Zhang, Yehong Wang, FengWang*
Inorg. Chem. Commun., 2019, 109, 107566
Here, we report the synthesis of an infinite coordination polymer (ICP) with 2,5-furan dicarboxylic acid (FDCA) and nickel acetate as precursors in a flow tubular microreactor in a continuous mode. Compared with the available synthesis methods, which usually span hours to days at elevated temperature, this strategy remarkably saves time and energy, and greatly increases the efficiency of s...
Hongji Li, Anon Bunrit, Jianmin Lu, Zhuyan Gao, Nengchao Luo, Huifang Liu, Feng Wang*
ACS Catal., 2019, 9, 8843-8851
Depolymerization of lignin meets the difficulty in cleaving the robust aryl ether bond. Herein, through installing an internal nucleophile in the β-O-4′ linkage, the selective cleavage of aryl ether was realized by the intramolecular substitution on aryl rings affording non-phenolic arylamine products. In particular, nitrogen-modified lignin models and lignin samples were employed to generate the iminyl radical under photocatalytic reduction, which acted as the internal nucleophile inducing aryl migration from O to the N atom. The following hydrolysis released primary arylamines and α-hydroxy ketones. Mechanism studies including electron spin resonance (ESR), fluorescence quenching experiments, and density functional theory (DFT) calculations proved the aryl migration pathway. This method enables access to non-phenolic arylamine products from lignin conversion.
Nengchao Luo, Tiziano Montini, Jian Zhang, Paolo Fornasiero, Emiliano Fonda, Tingting Hou, Wei Nie, Jianmin Lu, Junxue Liu, Marc Heggen, Long Lin, Changtong Ma, Min Wang, Fengtao Fan, Shengye Jin & Feng Wang*
Nat. Energy, 2019, 4(7), 575-584
We demonstrate the coproduction of H2 and diesel fuel precursors from lignocellulose-derived methylfurans via acceptorless dehydrogenative C−C coupling, using a Ru-doped ZnIn2S4 catalyst and driven by visible light. With this chemistry, up to 1.04 g /g catalyst/h of diesel fuel precursors (~41% of which are precursors of branched-chain alkanes) are produced with selectivity higher than 96%, together with 6.0 mmol/ g catalyst/ h of H2. Subsequent hydrodeoxygenation reactions yield the desired diesel fuels comprising straight- and branched-chain alkanes. We suggest that Ru dopants, substituted in the position of indium ions in the ZnIn2S4 matrix, improve charge separation efficiency, thereby accelerating C−H activation for the coproduction of H2 and diesel fuel precursors.
Yehong Wang, Mi Peng, Jian Zhang, Zhixin Zhang, Jinghua An, Shuyan Du, Hongyu An, Fengtao Fan, Xi Liu, Peng Zhai, Ding Ma*, Feng Wang*
Nat. Commun., 2018, 9, 5183
Selective conversion of an aqueous solution of mixed oxygenates produced by biomass fermentation to a value-added single product is pivotal for commercially viable biomass utilization. However, the efficiency and selectivity of the transformation remains a great challenge. Herein, we present a strategy capable of transforming ~70% of carbon in an aqueous fermentation mixture (ABE: acetone–butanol–ethanol–water) to 4-heptanone (4-HPO), catalyzed by tin-doped ceria (Sn-ceria), with a selectivity aas high as 86%. Water (up to 27 wt%), detrimental to the reported catalysts for ABE conversion, was beneficial for producing 4-HPO, highlighting the feasibility of the current reaction system. In a 300 h continuous reaction over 2 wt% Sn-ceria catalyst, the average 4-HPO selectivity is maintained at 85% with 50% conversion and > 90% carbon balance. This strategy offers a route for highly efficient organic-carbon utilization, which can potentially integrate biological and
Zhitong Zhao, Katie Chong, Jingyang Jiang, Karen Wilson, Xiaochen Zhang, Feng Wang*
Renew. Sustain. Energy Rev., 2018, 97, 580-591
The increasing emissions of carbon dioxide (CO2) are primarily driven by the rapid expansion of energy-intensive sectors such as the chemical industry. This work selects ethylene, one of the most important chemicals, as a model study to represent the low-carbon roadmap of chemical production. Four strategies improving the efficiency of fossil resource usage, developing the technology for carbon capture and storage (CCS), CO2 chemical conversion, and converting biomass resources into chemicals, are used to reduce CO2 emissions. A comprehensive analysis of the life cycle CO2 emissions of different ethylene production routes has been performed to compare their emission reduction potential. The results indicate that the BMTO (biomass to olefins via methanol-to-olefins) pathway releases the least CO2 (− 1.3 t CO2/t ethylene)
Jinghua An, Yehong Wang, Zhixin Zhang, Zhitong Zhao, Jian Zhang, Feng Wang*
Angew. Chem. Int. Ed., 2018, 57(38), 12308-12312
Quinazolinones, an important class of heterocyclic compounds, have been widely used in pharmaceuticals because of their biological activity. However, the efficient and economical synthesis of quinazolinones has remained a challenge. A novel synthetic approach has now been developed to produce quinazolinones from olefins, CO, and amines over heterogeneous Ru‐clusters/ceria catalyst in the absence of acids, bases, and oxidants. Furthermore, H2O is generated as the only by‐product. A series of quinazolinones with aromatic or non‐aromatic substituents can be obtained in yields of up to 99 %. The Ru‐clusters/ceria can be reused at least four times. The analysis of the E‐factor (environmental impact factor) for the synthesis of 2‐ethyl quinazolinone suggests that this system is more environmentally friendly than other processes reported previously.
Min Wang, Meijiang Liu, Hongji Li, Zhitong Zhao, Xiaochen Zhang, Feng Wang*
ACS Catal., 2018, 8(8), 6837-6843
Lignin is a renewable and abundant aromatic polymer found in plants. We herein propose a "cutting tail" methodology to produce phenol from lignin, which is achieved by combining Ru/CeO2 catalyst and CuCl2 oxidant via an oxidation–hydrogenation route. Phenol was obtained from separated poplar lignin with 13 wt % yield. Even raw biomass, such as poplar, birch, pine, peanut, bamboo willow, and straw, could be converted into phenol in 1–33 mg per gram of biomass.
Huifang Liu, Hongji Li, Jianmin Lu, Shu Zeng, Min Wang, Nengchao Luo, Shutao Xu, Feng Wang*
ACS Catal., 2018, 8(6), 4761-4771
Photocatalysis is a potentially promising approach to harvest aromatic compounds from lignin. However, the development of an active and selective solid photocatalyst is still challenging for lignin transformation under ambient conditions. We herein report a mild photocatalytic oxidative strategy for C–C bond cleavage of lignin β-O-4 and β-1 linkages using a mesoporous graphitic carbon nitride catalyst. Identifications by solid-state NMR techniques and density functional theory (DFT) calculations indicate that π–π stacking interactions are most likely present between the flexible carbon nitride surface and lignin model molecule. Besides, low charge recombination efficiency and high specific surface area (206.5 m2 /g) of the catalyst also contribute to its high catalytic activity. Mechanistic investigations reveal that photogenerated holes, as the main active species, trigger the oxidation and C–C bond cleavage of lignin models.
Yancheng Hu‡, Zhitong Zhao‡, Yanting Liu, Guangyi Li, Aiqin Wang, Yu Cong, Tao Zhang, Feng Wang*, Ning Li*
Angew. Chem. Int. Ed., 2018, 57(23), 6901-6905
Valuable polyester monomers and plasticizers—1,4‐cyclohexanedimethanol (CHDM), 1,4‐cyclohexanedicarboxylic acid (CHDA), and 1,2‐cyclohexanedicarboxylates—have been prepared by a new strategy. The synthetic processes involve a proline‐catalyzed formal [3+1+2] cycloaddition of formaldehyde, crotonaldehyde, and acrylate (or fumarate). CHDM is produced after a subsequent hydrogenation step over a commercially available Cu/Zn/Al catalyst and a one‐pot hydrogenation/oxidation/hydrolysis process yields CHDA, whereas 1,2‐cyclohexanedicarboxylate is obtained by a Pd/C‐catalyzed tandem decarbonylation/hydrogenation step.
Zhixin Zhang, Yehong Wang, Jianmin Lu, Jian Zhang, Mingrun Li, Xuebin Liu, Feng Wang*
ACS Catal., 2018, 8(4), 2635-2644
Defect chemistries of metal-doped CeO2 catalysts have attracted extensive scientific interests in heterogeneous catalysis. Here, we report the structure–activity relationship of CeO2 catalysts doped ...
Jinghua An‡, Yehong Wang‡, Jianmin Lu, Jian Zhang, Zhixin Zhang, Shutao Xu, Xiaoyan Liu, Tao Zhang, Martin Gocyla, Marc Heggen, Rafal E. Dunin-Borkowski, Paolo Fornasiero, Feng Wang*
J. Am. Chem. Soc., 2018, 140(11), 4172-4181
The interface of metal-oxide plays pivotal roles in catalytic reactions, but its catalytic function is still not clear. In this study, we report the high activity of nanostructured Ru/ceria (Ru-cluste...
Yehong Wang, Jian Zhang, Zhixin Zhang, Tingting Hou, Chaofeng Zhang, Jinghua An, Feng Wang*
Green Chem., 2018, 20, 1455-1458
Herein, a strategy is developed for efficient production of 1,3-propanediol via the hydrolysis of 1,3-dioxane by the in situ transformation of the co-product formaldehyde (HCHO) in the presence of Eu(...
Min Wang, Xiaochen Zhang, Hongji Li, Jianmin Lu, Meijiang Liu, Feng Wang*
ACS Catal., 2018, 8(2), 1614-1620
Catalytic valorization of lignin is a sustainable way to provide aromatics for the human society, which depends on the electronic structure of catalytic sites. We herein report the preparation of a carbon-modified nickel catalyst via carbothermal reduction of Ni-doped layered double hydroxides. Lignosulfonate (LS), a lignin resource from the pulp industry, was used as a renewable carbon precursor. The carbon residues in the nickel surface layer changed the 3d electron distribution of nickel, whi
Min Wang, Jiping Ma, Huifang Liu, Nengchao Luo, Zhitong Zhao, Feng Wang
ACS Catal., 2018, 8(3), 2129-2165
The use of biomass as a resource has developed rapidly in recent years, and various kinds of chemicals could be produced from biomass. Although biomass is annually renewable and abundant, it is important to process it in the most efficient way. Before rushing into biomass conversion, it is necessary to consider what chemicals are reasonably and economically produced from biomass. In this Review, we first analyzed the products from biomass based on the structural properties and economics. Taking
Hongji Li, Min Wang, Huifang Liu, Nengchao Luo, Jianmin Lu, Chaofeng Zhang, Feng Wang*
ACS Sustainable Chem. Eng., 2018, 6(3), 3748-3753
Conversion of lignin to aromatic compounds via C–C/C–O bond cleavage has been an attractive but challenging subject in recent years. We herein report the first protocol that converts lignin models and preoxidized lignin to isoxazole and aromatic nitrile. The isoxazole motif is constructed by condensation of β-hydroxyl ketone with hydroxylamine. Magnesium oxide promotes an oximation reaction and an intramolecular condensation. Aromatic nitriles and esters are obtained via Beckmann rearrangement o
Chaofeng Zhang, Zhipeng Huang, Jianmin Lu, Nengchao Luo, Feng Wang*
J. Am. Chem. Soc., 2018, 140(6), 2032-2035
Generation of controllable carbon radical under the assistance of N-oxyl radical is an efficient method for the activation of C–H bonds in hydrocarbons. We herein report that irradiation of α-Fe2O3 and N-hydroxyphthalimide (NHPI) under 455 nm light generates phthalimide-N-oxyl radical (PINO*), which after being formed by oxidation with holes, is confined on α-Fe2O3 surface. The half-life time of the confined radical reaches 22 s as measured by in situ electron paramagnetic resonance (EPR) after
Zhixin Zhang, Yehong Wang, Jianmin Lu, Min Wang, Jian Zhang, Xuebin Liu, Feng Wang*
Inorganics, 2017, 5(4), 75
We herein report the synthesis of 3-methyl-1,3-butanediol from isobutene and HCHO in water via a Prins condensation-hydrolysis reaction over CeO2, which is a water-tolerant Lewis acid catalyst. The CeO2 exhibits significant catalytic activity for the reaction, giving 95% HCHO conversion and 84% 3-methyl-1,3-butanediol selectivity at 150 °C for 4 h. The crystal planes of CeO2 have a signific...
Zhitong Zhao, Yong Liu, Feng Wang, Xuekuan Li, Shuping Deng, Jie Xu*, Wei Wei, Feng Wang*
J. Clean. Prod., 2017, 163, 285-292
Life cycle primary energy demand (PED) and greenhouse gas (GHG) emissions for the production of propylene in China (year 2013) have been carried out by considering several propylene production routes into account, such as catalytic cracking (CC), stream cracking (SC), coal-to-olefins (CTO) and coal-to-propylene (CTP), which cover the entire life cycle including: extraction and transportation...
Chaofeng Zhang, Feng Wang*
Chin. J. Catal., 2017. 38(7), 1102-1107
This perspective highlights recent progress on lignin β-O-4 conversion, which focuses on the combinatorial strategies leading to lignin β-O-4 cleavage beginning with adjacent fmunctional group modification, and provides insight into the challenges unexplored in this area.
Tingting Hou, Chaofeng Zhang, Yehong Wang, Zhenting Liu, Zhixin Zhang, Feng Wang*
Catal. Commun., 2017, 94(5), 56-59
A metal-free and efficient approach to N-arylpyrrolidines from arylamines and cyclic ethers catalyzed by hydrogen iodine is described. In this protocol, no additive is added and a wide range of N-arylpyrrolidines are synthesized with up to 99% yield. Reaction mechanism involving iodine radical is proposed.
Haijun Chen, Chao Liu, Min Wang, Chaofeng Zhang, Nengchao Luo, Yehong Wang, Hadi Abroshan, Gao Li*, Feng Wang*
ACS Catal., 2017, 7(5), 3632–3638
This work demonstrates the synthesis of an efficient photocatalyst, Au25(PPh3)10Cl2(SC3H6SiO3)5/TiO2, for selective oxidation of amines to imines. The photocatalyst is prepared via hydrolysis of Au25(PPh3)10Cl2[(SC3H6Si(OC2H5)3]5 nanoclusters in the presence of TiO2 support. The gold nanoclusters exhibit good photocatalytic activity using visible light and under mild thermal conditions for the selective oxidation with molecular oxygen (O2). The turnover frequency (TOF) of 4-methylbenzylamine oxi
Min Wang, Lihua Li, Jianmin Lu, Nengchao Luo, Xiaochen Zhang, Feng Wang*
Green Chem., 2017, 19(21), 5172-5177
Substituted imidazoles are traditionally synthesized by co-condensation of multiple feedstocks. Herein, we report a new route for the synthesis of substituted imidazoles via photocyclization of readily available amines at room temperature. The reaction is achieved by the visible-light-induced C–C/C–N bond coupling and subsequent dehydrogenation reaction over Mo–ZnIn2S4 as a heterogeneous photocatalyst. A wide range of amines were converted into the corresponding tri- and tetra-substituted imidaz
Tingting Hou, Yehong Wang, Jian Zhang, Mingrun Li, Jianmin Lu, Marc Heggen, Carsten Sievers, Feng Wang*
J. Catal., 2017, 353, 107-115
In many catalytic processes, metastable reaction intermediates are more valuable and desirable than final products. Here, we report Ni–Niδ+ clusters on ceria where the extent of reduction of nickel oxide/ceria in H2 has been optimized. This catalyst shows high selectivity in reducing nitrobenzene to azoxybenzene, the latter usually being metastable. Due to strong electronic metal–support interactions between Ni and ceria, mixed Ni–Niδ+ clusters are formed on ceria even after reduction at 500 °C
Chaofeng Zhang, Hongji Li, Jianmin Lu, Xiaochen Zhang, Katherine E MacArthur, Marc Heggen, Feng Wang*
ACS Catal., 2017, 7(5), 3419–3429
For lignin valorization, simultaneously achieving the efficient cleavage of ether bonds and restraining the condensation of the formed fragments represents a challenge thus far. Herein, we report a two-step oxidation–hydrogenation strategy to achieve this goal. In the oxidation step, the O2/NaNO2/DDQ/NHPI system selectively oxidizes CαH–OH to Cα═O within the β-O-4 structure. In the subsequent hydrogenation step, the α-O-4 and the preoxidized β-O-4 structures are further hydrogenated over a NiMo
Nengchao Luo, Min Wang, Hongji Li, Jian Zhang, Tingting Hou, Haijun Chen, Xiaochen Zhang, Jianmin Lu, Feng Wang*
ACS Catal., 2017, 7(7), 4571-4580
Obtaining high selectivity of aromatic monomers from renewable lignin has been extensively pursued but is still unsuccessful, hampered by the need to efficiently cleave C–O/C–C bonds and inhibit lignin proliferation reactions. Herein, we report a transfer hydrogenolysis protocol using a heterogeneous ZnIn2S4 catalyst driven by visible light. In this process, alcoholic groups (CαH–OH) of lignin act as hydrogen donors. Proliferation of phenolic products to dark substances is suppressed under visib
Tingting Hou, Nengchao Luo, Hongji Li, Marc Heggen, Jianmin Lu, Yehong Wang, Feng Wang*
ACS Catal., 2017, 7(6), 3850–3859
Selective cleavage of C–C bonds is pursued as a useful chemical transformation method in biomass utilization. Herein, we report a hybrid CuOx/ceria/anatase nanotube catalyst in the selective oxidation of C–C bonds under visible light irradiation. Using the lignin β-1 model as a substrate offers 96% yields of benzaldehydes. Characterization results by high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and energy-dispersive X-ray spectroscopy element (EDX) mapping
Yehong Wang, Jian Zhang, Haijun Chen, Zhixin Zhang, Chaofeng Zhang, Mingrun Li, Feng Wang*
Green Chem., 2017,19(1), 88-92
We herein report a new strategy of directly converting amines and CO to formamides with 100% atom utilization efficiency. It is suitable for up to 25 amine substrates with no additives. Ru/ceria is found to be an excellent catalyst for this reaction due the efficient co-activation of CO and amine on Ru species.
Huifang Liu, Min Wang, Hongji Li, Nengchao Luo, Shutao Xu, Feng Wang*
J. Catal., 2017, 346, 170-179
Catalytic oxidation of C-C bond is a key technology to transform petroleum-based as well as sustainable biomass feedstock into more valuable oxygenates. We herein describe a convenient and useful oxidation strategy of converting ketones into carboxylic acids using homogeneous copper catalyst without additives and with O2 as the terminal oxidant. A wide range of aryl and aliphatic ketones as well as β–O–4 lignin models were selectively oxidized to acids via C-C bond cleavage. Mechanism studies by
Min Wang, Jianmin Lu, Lihua Li, Hongji Li, Huifang Liu, Feng Wang*
J. Catal., 2017, 348, 160-167
Selective oxidative cleavage of C-C bond is pivotal for producing functionalized molecules, useful for organic synthesis and biomass utilization. We herein report the oxidative C(OH)-C bond cleavage of secondary alcohols to acids over a copper/1, 10-phenanthroline complex with molecular oxygen as the oxidant. A wide range of secondary alcohols are converted into acids with up to 98% yields. More interestingly, it is effective for breaking up lignin model systems into acids, which is rarely achie
Min Wang, Lihua Li, Jianmin Lu, Hongji Li, Xiaochen Zhang, Huifang Liu, Nengchao Luo, Feng Wang*
Green Chem., 2017, 19(3), 702-706
Depolymerisation of lignin to aromatics is a challenging task. We herein report that a Cu(OAc)2/BF3·OEt2 catalyst is effective in simultaneously cleaving C–C bonds in β-1 and β-O-4 ketones, yielding esters and phenols. In-depth studies show that C–H bond activation is the rate determining step for C–C bond cleavage. BF3·OEt2 promotes the reaction via activating the β-C–H bond. This study offers the potential to obtain aromatic esters from lignin.
Zhixin Zhang, Yehong Wang, Min Wang, Jianmin Lu, Chaofeng Zhang, Lihua Li, Jingyang Jiang, Feng Wang*
Catal. Sci. Technol., 2016, 6(6), 1693-1700
We herein report the oxidative C–C coupling of ketones and primary alcohols to produce α,β-unsaturated ketones in the absence of base additives. This cascade synthetic reaction was conducted at 150 °C in 12 h using a heterogeneous CeO2 catalyst. The conversion of acetophenone reached 74% with 89% selectivity to chalcone. A correlation between the CeO2 crystal plane and catalytic performance is established as the catalytic activities decrease in the sequence of (110) > (111) > (100). Characterization using Raman spectroscopy, CO2 temperature-programmed desorption (CO2-TPD), and in situ active site-capping tests has shown that the unusual catalysis of the CeO2 catalyst is attributed to the coexistence of basic and redox active sites. These sites synergistically catalyze the oxidation of alcohols to aldehydes and the aldol condensation to ketones. Moreover, the CeO2 catalyst can be reused several times after calcination to remove the surface-adsorbed substances.
Zhixin Zhang, Yehong Wang, Jianmin Lu, Chaofeng Zhang, Min Wang, Mingrun Li, Xuebin Liu, Feng Wang*
ACS Catal., 2016, 6(12), 8248–8254
Conversion of low-carbon olefins to higher alcohols or olefins via the formation of C–C bonds is an increasingly important topic. We herein report an example of converting isobutene and formaldehyde (38 wt % aqueous solution) to 3-methyl-1,3-butanediol (MBD), a precursor for isoprene. The reaction occurs through a Prins condensation–hydrolysis reaction over a praseodymium (Pr)-doped CeO2 catalyst. The best MBD yield (70%) is achieved over the Pr-doped CeO2 catalyst. Catalyst characterizations wi
Nengchao Luo, Min Wang, Hongji Li, Jian Zhang, Huifang Liu, Feng Wang*
ACS Catal., 2016, 6(11), 7716–7721
One of the challenges of depolymerizing lignin to valuable aromatics lies in the selective cleavage of the abundant C–O bonds of β-O-4 linkages. Herein we report a photocatalytic oxidation–hydrogenolysis tandem method for cleaving C–O bonds of β-O-4 alcohols. The Pd/ZnIn2S4 catalyst is used in the aerobic oxidation of α-C–OH of β-O-4 alcohols to α-C═O with 455 nm light, and then a TiO2–NaOAc system is employed for cleaving C–O bonds neighboring the α-C═O bonds through a hydrogenolysis reaction b
Chaofeng Zhang, Jianmin Lu, Xiaochen Zhang, Katherine E MacArthur, Marc Heggen, Hongji Li, Feng Wang*
Green Chem., 2016,18(24), 6545-6555
Efficient cleavage of lignin β-O-4 ether bonds to produce aromatics is a challenging and attractive topic. Recently a growing number of studies reveal the initial oxidation of CαHOH to Cα=O can decrease the β-O-4 bond dissociation energy (BDE) from 274.0 kJ•mol-1 to 227.8 kJ•mol-1, and thus the β-O-4 bond is more readily cleaved in the subsequent transfer hydrogenation, or acidolysis. Here we show that the first reaction step, except in the above-mentioned pre-oxidation methods, can be a Cα-OH b
Min Wang, Jianmin Lu, Xiaochen Zhang, Lihua Li, Hongji Li, Nengchao Luo, Feng Wang*
ACS Catal., 2016, 6(9), 6086–6090
We herein report a two-step strategy for oxidative cleavage of lignin C–C bond to aromatic acids and phenols with molecular oxygen as oxidant. In the first step, lignin β-O-4 alcohol was oxidized to β-O-4 ketone over a VOSO4/TEMPO [(2,2,6,6-tetramethylpiperidin-1-yl)oxyl)] catalyst. In the second step, the C–C bond of β-O-4 linkages was selectively cleaved to acids and phenols by oxidation over a Cu/1,10-phenanthroline catalyst. Computational investigations suggested a copper-oxo-bridged dimer w
Jianmin Lu, Min Wang, Xiaochen Zhang, Andreas Heyden, Feng Wang*
ACS Catal., 2016, 6(8), 5589–5598
Lignin in lignocellulosic biomass is the only renewable source for aromatic compounds, and effective valorization of lignin remains a significant challenge in biomass conversion processes. We have performed density functional theory calculations and experiments to investigate the cleavage mechanism of the C–O ether bond in the lignin model compound 2-phenoxy-1-phenylethanol with a β-O-4 linkage over a Pd(111) catalyst surface model. We propose the favorable reaction pathway to proceed as follows
Haijun Chen, Chao Liu, Min Wang, Chaofeng Zhang, Gao Li*, Feng Wang*
Chin. J. Catal., 2016, 37(10), 1787-1793
Well-defined gold nanoclusters with average size less than 2 nm have emerged as a new and novel catalyst. The gold nanocluster loaded on the oxide surface usually aggregates to larger particles at high temperature (> 300 °C), which is caused by the removal of the surface ligands. We herein present a novel method to prepare Au25 cluster catalyst (∼1.3 nm) with high thermal stability (up to...
Xiaochen Zhang, Min Wang, Chaofeng Zhang, Jianmin Lu, Yehong Wang, Feng Wang*
RSC Adv., 2016, 6, 70842-70847
Crystalline Mo–V–O oxides have been used as a catalyst for the hydrolysis and alcoholysis of propylene oxide to diols and ethers, respectively. Relationships between the active crystal facet, the acidity of Mo–V–O catalysts and the activity have been established. Our results indicate that the a–b plane is the active facet for the hydrolysis reaction.
Chaofeng Zhang, Xu Wang, Mingrun Li, Zhixin Zhang, Yehong Wang, Rui Si, Feng Wang
Chin. J. Catal., 2016, 37(9), 1569-1577
We present an efficient approach for the chemoselective synthesis of arylamines from nitroarenes and formate over an oxygen-implanted MoS2 catalyst (O-MoS2). O-MoS2 was prepared by incomplete sulfidation and reduction of an ammonium molybdate precursor. A number of Mo–O bonds were implanted in the as-synthesized ultrathin O-MoS2 nanosheets. As a consequence of the different coordination ge...
Chaofeng Zhang, Zhixin Zhang, Xu Wang, Mingrun Li, Jianmin Lu, Rui Si, Feng Wang*
Appl. Catal. A: Gen., 2016, 525, 85-93
We present an efficient approach for chemoselective synthesis of various functionalized arylamines from nitroarenes over an oxygen-implanted MoS2 catalyst (O-MoS2). The HRTEM, XRD, XPS, Raman, EXAFS and NH3-TPD characterizations show the existence of MoIVOx structure and abundant coordinative unsaturated (CUS) Mo sites in the 2D-layer structure of O-MoS2. In the transfer hydrogenation of nitro...
Chaofeng Zhang, Jianmin Lu, Mingrun Li, Yehong Wang, Zhe Zhang, Haijun Chen, Feng Wang*
Green Chem., 2016, 18(8), 2435-2442
We present an experimental and computational study of the elementary steps of hydrazine hydrogen transfer on crystalline MoO2, and demonstrate its unique bifunctional metallic-basic properties in a catalytic hydrogenation reaction. Density functional theory (DFT) calculations suggest that the stepwise hydrogen transfer via the prior cleavage of the N–H bond rather than the N–N bond, is the key step to create the dissociated hydride and proton species on the dual Mo and O sites, marking its diffe
Min Wang, Jiping Ma, Miao Yu, Zhe Zhang, Feng Wang*
Catal. Sci. Technol., 2016, 6, 1940-1945
We herein report the transition metal oxide-catalyzed synthesis of azobenzenes through the oxidative coupling of anilines. An octahedral molecular sieve of manganese oxide, OMS-2, exhibited the best activity and selectivity. Nine examples of symmetric azobenzenes and twenty unsymmetric ones were synthesized with 62–99% conversion and 64–99% selectivity. In the aniline cross-coupling reactions...
Zhe Zhang, Min Wang, Chaofeng Zhang, Zhixin Zhang, Jianmin Lua, Feng Wang*
Chem. Commun., 2015,51(44), 9205-9207
Heterogeneously catalyzed synthesis of quinazolinones or quinazolines is reported in this study. An α-MnO2 catalyst is found to be highly active and selective in the oxidative cyclization of anthranilamides or aminobenzylamines with alcohols using TBHP as an oxidant. This protocol exhibits a broad substrate scope, and is operationally simple without an additive.
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