Non-noble metal-based catalysts for acetylene semihydrogenation:from thermocatalysis to sustainable catalysis

Selective semihydrogenation of acetylene in raw olefin streams to ethylene is a key industrial reaction to produce polymer-grade feeds for the manufacture of corresponding polymers.The currently used process in industry is the thermocatalytic acetylene semihydrogenation with pressurized hydrogen and Pd-based catalysts at relatively high temperatures.The high cost of Pd urgently desires the design of non-noble metal-based catalysts.However,non-noble metal-based catalysts commonly require much higher reaction temperatures than Pd-based catalysts because of their poor intrinsic activity.Therefore,aiming at increasing economic efficiency and sustainability,various strategies are explored for developing non-noble metal-based catalysts for thermocatalytic and green acetylene semihydrogenation processes.In this review,we systematically summarize the recent advances in catalytic technology from thermocatalysis to sustainable alternatives,as well as corresponding regulation strategies for designing high-performance non-noble metal-based catalysts.The crucial factors affecting catalytic performance are discussed,and the fundamental structure-performance correlation of catalysts is outlined.Meanwhile,we emphasize current challenging issues and future perspectives for acetylene semihydrogenation.This review will not only promote the rapid exploration of non-noble metal-based catalysts for acetylene semihydrogenation,but also advance the development of sustainable processes like electrocatalysis and photocatalysis.

Advances of photothermal chemistry in photocatalysis,thermocatalysis,and synergetic photothermocatalysis for solar-to-fuel generation

The urgency of reducing pollutants and greenhouse gas emissions while maintaining fuel supply for the development of society remains one of the greatest challenges.Solar energy,a clean and sustainable energy resource,can be converted into fuels through solar-driven catalysis,and this provides an attractive solution for future energy demand.The current development of photothermal catalysis(PTC)based on the integration of solar thermal and photochemical contributions is becoming increasingly popular for full spectrum utilization.The combination of the thermochemical and photochemical processes synergistically drives the catalytic reactions efficiently under relatively mild conditions.In this review,the mechanisms of PTC are classified based on driving forces and the benefits of photothermal effects in different PTC reactions are discussed.Subsequently,the techniques for differentiating and quantifying the various effects of PTC,including experimental designs,thermometry characterization techniques,and computational studies,are summarized.Then,the major determinant properties and architectural designs for efficient photothermal catalysts are offered.Moreover,applications for fuel generation through water splitting and carbon dioxide reduction are reviewed.Finally,the current challenges and future directions of PTC are presented.This article aims to provide a comprehensive review of the current advances in PTC along with a guide for understanding the mechanisms and rational material designs to pursue solar fuel that would diversify and increase the sustainability of our energy supply.

Computational Screening of Pt1@Ti_(3)C_(2)T_(2)(T=O,S)MXene Catalysts for Water-Gas Shift Reaction

Single-atom catalysts(SACs)provide an oppor-tunity to elucidate the catalytic mechanism of complex reactions in heterogeneous catalysis.The low-temperature water-gas shift(WGS)reaction is an important industrial technology to obtain high purity hydrogen.Herein,we study the catalytic activity of Pt1@Ti_(3)C_(2)T_(2)(T=O,S)SACs,where one subsurface Ti atom with three T vacancies in the functionalized Ti_(3)C_(2)T_(2)(T=O,S)MXene is substituted by one Pt atom,for the low-temperature show that Pt1@Ti_(3)C_(2)T_(2)provides an excellent platform for the WGS reaction by its bowl-shaped vacancy derived from the Pt1 single atom and three T defects surrounding it.Especially,Pt1@Ti_(3)C_(2)S_(2)SAC has higher catalytic performance for the WGS reaction,due to the weaker electronegativity of the S atom than the O atom,which significantly reduces the energy barrier of H*migration in the WGS reaction,which is often the rate-determining step.In the most favorable redox mechanism of the WGS reaction on Pt1@Ti_(3)C_(2)S_(2),the rate-determining step is the dissociation of OH*into O*and H*with the energy barrier as low as 1.12 eV.These results demonstrate that Pt1@Ti_(3)C_(2)S_(2)is promising in the application of MXenes for low-temperature WGS reactions.

Catalytic methane removal to mitigate its environmental effect

Large reserve of methane,in the form of natural gas and methane hydrate,has been discovered and it has been intensively used as a fuel,or as a building block for the chemical synthesis.However,severe environmental and climatic issues caused by the leakage of methane during the production,transportation and use of methane are overlooked.This offers incentives for the catalytic removal of methane.Nevertheless,due to the inert nature of methane molecules,the activation of methane via thermocatalysis requires harsh reaction conditions.The high reaction temperature not only increases the capital cost but also accelerates the deactivation of catalysts due to sintering and/or coking.The development of robust and stable catalysts with a low operating temperature has become the focus of the research on thermocatalytic methane oxidation.Photocatalysis,which uses the energy of photons instead of heat to drive chemical reactions under ambient conditions,offers another approach to methane removal.This review will cover the development of high-efficiency catalysts for methane combustion in both thermo-and photocatalysis.Moreover,the fundamental understanding of the active sites,surface chemistry and reaction pathway will also be discussed.Finally,the challenges facing in the catalytic removal of methane will be summarized and potential solutions will be provided.This review will be of interest to researchers in the field of heterogeneous catalysis,materials design,and chemical engineering.

Recent advances in the catalytic production of bio-based diol 2,5-bis(hydroxymethyl)furan

Biomass-derived 2,5-bis(hydroxymethyl)furan(BHMF)has received great attention and interest due to its broad application prospects in polyesters and medicine.Over the past decades,the catalytic systems including thermocatalytic,biocatalytic,electrocatalytic,and photocatalytic hydrogenation of 5-hydroxymethylfurfural(HMF)into BHMF have been developed to a great extent.To understand the present status and challenges of BHMF production,this review systematically evaluates recent findings and developments of HMF hydrogenation through various reaction systems,with an emphasis on catalyst screening,synthesis processes,and reaction mechanism.Furthermore,a few potential research trends are also proposed,in order to provide innovative ideas for further exploration of BHMF synthesis in a simpler,efficient,and economical way.

Polyoxometalates based compounds for green synthesis of aldehydes and ketones

Molecular oxygen within Polyoxometalates(POMs)based compounds are ideal oxidants with high atom economy and its use results in the production of water as the only byproduct.Significant progress has been made in the development of catalytic methods for aerobic alcohol oxidation to have aldehydes and ketones with POMs based compounds.They are alternative to the use of traditional hypervalent iodine catalyst systems which are with molecular oxygen as a terminal oxidant.Further,POMs based catalysts can be applied to catalytic reactions with different modes of energization such as thermocatalysis,photocatalysis and electrocatalysis.This review summarizes the frontier advances in polyoxometalates for catalytic alcohol selective oxidation in thermocatalytic,electrocatalytic,and photocatalytic applications.The three advantages of POM catalysts in terms of performance,economy,and environmental protection are highlighted.These include the use of sol-gel and electrostatic assembly methods to increase the reaction surface area,reduce the use of precious metals,and improve the stability of POMs catalysts.The field of selective alcohol oxidation is advanced.Finally,the challenges of preparing more efficient and“green”catalysts are presented.

Recent advance in single-atom catalysis

Single-atom catalysts(SACS) have obtained a great deal of attention in many catalytic fields due to the high atom utilization efficiency and high catalytic activity.Recently,great achievements on S ACs have been made for thermocatalysis,electrocatalysis,and photocatalysis which play an important role in obtaining value-added products.However,it remains a great challenge to fabricate S ACs with high metal loading and investigate their reaction mechanisms.Therefore,it is necessary to highlight the recent development of S ACs in these fields to guide future research.In this review,we overviewed the thermocatalysis applications of SACs in CO oxidation,preferential oxidation of CO,water-gas shift reaction,methane conversion,methanol steam reforming,aqueous-phase reforming of methanol,hydrogenation of alkynes and dienes,hydrogenation of CO,and hydrogenation of substituted nitroarenes.Moreover,the oxygen reduction reaction(ORR),hydrogen evolution reaction(HER),oxygen evolution reaction(OER),CO2 reduction reaction(CO2 RR),and N2 reduction reaction(N2 RR) for photocatalytic and electrocatalytic fields were also overviewed.Lastly,the opportunities and challenges of SACs were pointed out.

Progress of Nb-containing catalysts for carbon dioxide reduction:a minireview

Nb-containing catalysts have the potential to catalyze carbon dioxide(CO_(2))reduction due to their strong surface acidity and CO_(2)activation sites.Still,they have not been widely used in the development and design of catalysts due to the theoretical/cost/safety limitations.Related advances have been continuously reported in the literature,demonstrating to some extent the promise of catalytic applications of Nb-containing catalysts in this area.In this minireview,we discuss the structure-activity relationships of Nb-containing catalysts for photo-,electro-,and thermocatalytic reduction of CO_(2).The engineering strategies of Nb-containing catalysts for enhancing the conversion and selectivity of CO_(2)reduction are discussed,ranging from Nb doping,noble metal decoration,surface acidity adjustment,oxygen vacancy engineering,and heterojunction construction to Nb or Nb_(2)O_(5) particle decoration.The theoretical calculation research for the possible reaction paths and product selectivity is also discussed.Finally,the prospects for designing and optimizing Nb-containing catalysts are proposed.With a deep understanding of catalytic activity and reaction mechanism,this minireview is expected to present the optimization of the Nb-containing catalysts for efficient and highly selective CO_(2)reduction.