Developing biomass platform compounds into high value-added chemicals is a key step in renewable resource utilization.Herein,we report porous carbon-supported Ni-ZnO nanoparticles catalyst(Ni-ZnO/AC)synthesized via lo...Developing biomass platform compounds into high value-added chemicals is a key step in renewable resource utilization.Herein,we report porous carbon-supported Ni-ZnO nanoparticles catalyst(Ni-ZnO/AC)synthesized via low-temperature coprecipitation,exhibiting excellent performance for the selective hydrogenation of 5-hydroxymethylfurfural(HMF).A linear correlation is first observed between solvent polarity(E_(T)(30))and product selectivity within both polar aprotic and protic solvent classes,suggesting that solvent properties play a vital role in directing reaction pathways.Among these,1,4-dioxane(aprotic)favors the formation of 2,5-bis(hydroxymethyl)furan(BHMF)with 97.5%selectivity,while isopropanol(iPrOH,protic)promotes 2,5-dimethylfuran production with up to 99.5%selectivity.Mechanistic investigations further reveal that beyond polarity,proton-donating ability is critical in facilitating hydrodeoxygenation.iPrOH enables a hydrogen shuttle mechanism where protons assist in hydroxyl group removal,lowering the activation barrier.In contrast,1,4-dioxane,lacking hydrogen bond donors,stabilizes BHMF and hinders further conversion.Density functional theory calculations confirm a lower activation energy in iPrOH(0.60 eV)compared to 1,4-dioxane(1.07 eV).This work offers mechanistic insights and a practical strategy for solvent-mediated control of product selectivity in biomass hydrogenation,highlighting the decisive role of solvent-catalyst-substrate interactions.展开更多
The activated carbon-supported TiO2 nanoparticles(TiO2/AC)were prepared by a properly controlled sol-gel method.The effects of activated carbons(AC)support on inactivated properties of TiO2 nanoparticles were evaluate...The activated carbon-supported TiO2 nanoparticles(TiO2/AC)were prepared by a properly controlled sol-gel method.The effects of activated carbons(AC)support on inactivated properties of TiO2 nanoparticles were evaluated by photocatalytic inactivation experiments of Escherichia coli.The key factors affecting the inactivation effciency were investigated,including electric power of lamp, temperature,and pH values.The results show that the TiO2/AC composites have high inactivation properties of E.coli in compari...展开更多
As a main oxidizer in solid composite propellants,ammonium perchlorate(AP)plays an important role because its thermal decomposition behavior has a direct influence on the characteristic of solid composite propellants....As a main oxidizer in solid composite propellants,ammonium perchlorate(AP)plays an important role because its thermal decomposition behavior has a direct influence on the characteristic of solid composite propellants.To improve the performance of solid composite propellant,it is necessary to take measures to modify the thermal decomposition behavior of AP.In recent years,transition metal oxides and carbon-supported transition metal oxides have drawn considerable attention due to their extraordinary catalytic activity.In this review,we highlight strategies to enhance the thermal decomposition of AP by tuning morphology,varying the types of metal ion,and coupling with carbon analogue.The enhanced catalytic performance can be ascribed to synergistic effect,increased surface area,more exposed active sites,and accelerated electron transportation and so on.The mechanism of AP decomposition mixed with catalyst has also been briefly summarized.Finally,a conclusive outlook and possible research directions are suggested to address challenges such as lacking practical application in actual formulation of solid composite propellant and batch manufacturing.展开更多
Carbon-supported copper catalyst was prepared for the first time in one-step with copper nitrate and corn stalk through calcination under different temperatures. Uniformly dispersed nanoparticles were obtained and wer...Carbon-supported copper catalyst was prepared for the first time in one-step with copper nitrate and corn stalk through calcination under different temperatures. Uniformly dispersed nanoparticles were obtained and were identified to be Cu（0） and Cu（Ⅰ） in XRD patterns. Excellent catalytic activity and selectivity were achieved in the N-arylation of pyrazole under ligand and protection gas free conditions. About90.4% of product yield was achieved with only 0.5 mol% of copper catalyst（Cu-C-300）, which was considerably more efficient than previous reports. XPS results suggested that the N-arylation of pyrazole activity was closely related to the surface Cu（Ⅰ） species.展开更多
By evaluating the SEM images,specific surface area,and the catalytic synthesis reaction conditions of an activated carbon-supported p-toluenesulfonic acid catalyst,and comparing the physical and chemical properties,in...By evaluating the SEM images,specific surface area,and the catalytic synthesis reaction conditions of an activated carbon-supported p-toluenesulfonic acid catalyst,and comparing the physical and chemical properties,infrared spectra,nuclear magnetic resonance spectra,oxidation stability,thermal stability,hydrolytic stability,and extreme pressure anti-wear performance of the synthesized trihydroxymethylpropyl trioleate with imported reference esters,the feasibility of its application as a substitute was investigated.The results indicated that the activated carbon-supported p-toluenesulfonic acid catalyst exhibited loose porosity,high specific surface area,and high esterification efficiency.When synthesized under optimal conditions,the yield rate of trihydroxymethylpropyl trioleate reached 99.3%,with a simple separation process that did not require additional steps such as neutralization and washing and generated minimal wastewater.The physical and chemical properties of the synthesized trihydroxymethylpropyl trioleate were comparable to those of the reference ester in terms of color,viscosity,viscosity index,flash point,and pour point.Moreover,the peak position and peak height in the infrared and nuclear magnetic carbon spectra were essentially the same.Through comprehensive evaluations and comparisons of various properties,it was determined that the performance of trihydroxymethylpropyl trioleate was comparable to that of the imported reference esters.展开更多
Carbon-supported transition metal single atoms are promising oxygen reduction reaction(ORR)electrocatalyst.Since there are many types of carbon supports and transition metals,the accurate prediction of the components ...Carbon-supported transition metal single atoms are promising oxygen reduction reaction(ORR)electrocatalyst.Since there are many types of carbon supports and transition metals,the accurate prediction of the components with high activity through theoretical calculations can greatly save experimental time and costs.In this work,the ORR catalytic properties of 180 types single-atom catalysts(SACs)composed of the eight representative carbon-based substrates(graphdiyne,C_(2)N,C_(3)N_(4),phthalocyanine,C-coordination graphene,N-coordination graphene,covalent organic frameworks and metal-organic frameworks)and 3d,4d,and 5d transition metal elements are investigated by density functional theory(DFT).The adsorption free energy of OH^(*) is proved a universal descriptor capable of accurately prediction of the ORR catalytic activity.It is found that the oxygen reduction reaction overpotentials of all the researched SACs follow one volcano shape very well with the adsorption free energy of OH^(*).Phthalocyanine,N-coordination graphene and metal-organic frameworks stand out as the promising supports for single metal atom due to the relatively lower overpotentials.Notably,the Co-doped metal-organic frameworks,Ir-doped phthalocyanine,Co-doped N-coordination graphene,Co-doped graphdiyne and Rh-doped phthalocyanine show extremely low overpotentials comparable to that of Pt(111).The study provides a guideline for design and selection of carbon-supported SACs toward oxygen reduction reaction.展开更多
Breakthroughs in energy storage and conversion devices depend heavily on the exploration of low-cost and high-performance materials.Carbon-supported electrocatalysts with dimensional varieties have recently attracted ...Breakthroughs in energy storage and conversion devices depend heavily on the exploration of low-cost and high-performance materials.Carbon-supported electrocatalysts with dimensional varieties have recently attracted significant attention due to their strong structural flexibility and easy accessibility.Nevertheless,understanding the connection between their electronic,structural properties,and catalytic performance must remain a top priority.Synchrotron radiation(SR)X-ray absorption spectroscopy(XAS)techniques,including hard XAS and soft XAS,are recognized as efficient and comprehensive platforms for probing the surface,interface,and bulk electronic structure of elements of interest in the materials community.In the past decade,the flourishing development of materials science and advanced characterization technologies have led to a deeper understanding at different temporal,longitudinal,and spatial scales.In this review,we briefly describe the concept of XAS techniques and summarize their recent progress in addressing scientific questions on carbon-supported electrocatalysts through the development of advanced instruments and experimental methods.We then discuss the remaining challenges and potential research directions in nextgeneration materials frontiers,and suggest challenges and perspectives for shedding light on the structure–activity relationship.展开更多
Proton exchange membrane fuel cells are playing an increasing role in postpandemic economic recovery and climate action plans.However,their performance,cost,and durability are significantly related to Pt-based electro...Proton exchange membrane fuel cells are playing an increasing role in postpandemic economic recovery and climate action plans.However,their performance,cost,and durability are significantly related to Pt-based electrocatalysts,hampering their large-scale commercial application.Hence,considerable efforts have been devoted to improving the activity and durability of Pt-based electrocatalysts by controlled synthesis in recent years as an effective method for decreasing Pt use,and consequently,the cost.Therefore,this review article focuses on the synthesis processes of carbon-supported Pt-based electrocatalysts,which significantly affect the nanoparticle size,shape,and dispersion on supports and thus the activity and durability of the prepared electrocatalysts.The reviewed processes include(i)the functionalization of a commercial carbon support for enhanced catalyst-support interaction and additional catalytic effects,(ii)the methods for loading Pt-based electrocatalysts onto a carbon support that impact the manufacturing costs of electrocatalysts,(iii)the preparation of spheri-cal and nonspherical Pt-based electrocatalysts(polyhedrons,nanocages,nanoframes,one-and two-dimensional nanostruc-tures),and(iv)the postsynthesis treatments of supported electrocatalysts.The influences of the supports,key experimental parameters,and postsynthesis treatments on Pt-based electrocatalysts are scrutinized in detail.Future research directions are outlined,including(i)the full exploitation of the potential functionalization of commercial carbon supports,(ii)scaled-up one-pot synthesis of carbon-supported Pt-based electrocatalysts,and(iii)simplification of postsynthesis treatments.One-pot synthesis in aqueous instead of organic reaction systems and the minimal use of organic ligands are preferred to simplify the synthesis and postsynthesis treatment processes and to promote the mass production of commercial carbon-supported Pt-based electrocatalysts.展开更多
Non-precious metal single-atom catalysts(NPM-SACs)with unique electronic structures and coordination environments have gained much attention in electrocatalysis owing to their low cost,high atomic utilization,and high...Non-precious metal single-atom catalysts(NPM-SACs)with unique electronic structures and coordination environments have gained much attention in electrocatalysis owing to their low cost,high atomic utilization,and high performance.NPM-SACs on carbon support(NPM-SACs/CS)are promising because of the carbon substrate with a large surface area,excellent electrical conductivity,and high chemical stability.This review provides an overview of recent developments in NPM-SACs/CS for the electrocatalytic field.First,the state-of-the-art synthesis methods and advanced characterization techniques of NPM-SACs/CS are discussed in detail.Then,the structural adjustment strategy of NPM-SACs/CS for optimizing electrocatalytic performance is introduced concisely.Furthermore,we provide a comprehensive summary of recent advances in developing NPM-SACs/CS for important electrochemical reactions,including carbon dioxide reduction reaction,hydrogen evolution reaction,oxygen evolution reaction,oxygen reduction reaction,and nitrogen reduction reaction.In the end,the existing challenges and future opportunities of NPM-SACs/CS in the electrocatalytic field are highlighted.展开更多
Activated carbon （AC）-supported copper or zinc made from ion exchange resin （IRCu-C and IRZn-C） have an increased metal load of 557.3 mg·g^-1 and 502.8 mg·g^-1 compared to those prepared by the tradition...Activated carbon （AC）-supported copper or zinc made from ion exchange resin （IRCu-C and IRZn-C） have an increased metal load of 557.3 mg·g^-1 and 502.8 mg·g^-1 compared to those prepared by the traditional method involving impregnation with AC and copper （II） citrate or zinc citrate solution （LaCu-C and LaZn-C） of 12.9 mg·g^-1 and 46.0 mg·g^-1 respectively. When applied to decompose 2,2＇,4,4＇,5,5＇-hexachlorobiphenyl at 250 ℃, IRCu-C achieved higher activity of 99.0% decomposition efficiency than LaCu-C of 84.7%, IRZn-C of 90.5% and LaZn-C of 62.7%. When the reaction temperature rose to 350 ℃, all the four kinds of reactants can decompose PCB- 153 with efficiency above 90%. Further, X-ray photoelec- tron spectroscopy characterization of IRCu-C before and after the reaction indicated transformation of 19.1% of Cu atoms into Cu^2＋, illustrating that Cu is the active ingredient or electron donor promoting the decomposition of PCB- 153. The mechanism underlying this process differs from a traditional H donor. However, there is no significant change on the surface of IRZn-C before and after the reaction, suggesting that Zn acts as catalyst during the process of PCB-153 decomposition.展开更多
The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum c...The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum catalysts(Pt/C/PTFE) with high efficiency as reported previously for LPCE were prepared and comprehensive performance evaluation method is applied to evaluate the separation behaviors of LPCE systematically. Experimental results indicate that the optimum reaction temperature of 60–80℃ and the molar feed ratio G/L of 1.5–2.5 would lead to higher separation efficiencies. As to the packing method, a random packing mode with a packing ratio of hydrophobic catalysts 0.25 is recommended. In addition, thermodynamic analysis corresponds well with experimental results under lower temperature and G/L, while the suppression of kinetic factors should not be neglected when T > 80℃ and G/L > 1.5.展开更多
Currently,pyrolysis as the most widely used method still has some key issues not well resolved for synthesis of carbon-supported single-atom catalysts(C-SACs),e.g.,the sintering of metal atoms at high temperature as w...Currently,pyrolysis as the most widely used method still has some key issues not well resolved for synthesis of carbon-supported single-atom catalysts(C-SACs),e.g.,the sintering of metal atoms at high temperature as well as the high cost and complicated preparations of precursors.In this report,molten salts are demonstrated to be marvellous medium for preparation of C-SACs by pyrolysis of small molecular precursors(ionic liquid).The ultrastrong polarity on one hand establishes robust interaction with precursor and enables better carbonization,resulting in largely enhanced yield.On the other hand,the aggregation of metal atoms is effectively refrained while no nanoparticle or cluster is formed.By this strategy,a C-SAC with atomically dispersed Fe-N_(4) sites and a high specific area over 2000 m^(2) g^(-1) is obtained,which illustrates high ORR activity in both acid and alkaline media.Moreover,this SAC exhibits superior methanol tolerance and stability after acid soaking at 85℃ for 48 h.It is believed that the molten-salts-assisted pyrolysis can be developed into a routine strategy as it not only can largely simply the synthesis of C-SACs,but also can be extended to prepare other types of SACs.展开更多
Carbon-supported single-atom catalysts(C-SACs)have been demonstrated as a strategy to promote the reversible conversion reaction of metal sulfide anodes in sodium-ion batteries(SIBs).However,the design principle of pr...Carbon-supported single-atom catalysts(C-SACs)have been demonstrated as a strategy to promote the reversible conversion reaction of metal sulfide anodes in sodium-ion batteries(SIBs).However,the design principle of promising C-SACs remains lacking for obtaining highly reversible metal sulfide anodes.We designed a phosphorus-doped carbon-supported single-atom Mn catalyst(PC-SAMn)with an asymmetrical dual active center.The sulfiphilic Mn and sodiophilic P active centers adsorb discharged Na 2S through Mn-S d-p and P-Na s-p orbital hybridizations.The asymmetrical dual active center induced the asymmetrical adsorption configuration of Na 2S,which efficiently weakened Na-S bond strength and facilitated the decomposition of Na 2S during charging.As a result,the designed catalyst enables typical MoS_(2) with a record-high compositional reversible degree of 89.61%and a low capacity decay ratio of only 0.18%per 100 cycles during 2000 cycles.The research establishes the“orbital hybridization-molecular structure-catalytic activity”relationship for guiding the design of highly reversible conversion-type materials.展开更多
The ammonia electrooxidation reaction(AmER)has attracted considerable attention due to its potential for hydrogen storage and transportation,as well as its possible application in direct ammonia fuel cells.In the pres...The ammonia electrooxidation reaction(AmER)has attracted considerable attention due to its potential for hydrogen storage and transportation,as well as its possible application in direct ammonia fuel cells.In the present work,we studied ammonia electrooxidation on carbon-supported Pt/C nanoparticles(NPs)of four average sizes of 1.3,2.2,2.8,and 4.2 nm.Carbon-supported Pt NPs with a 20 wt% metal loading were synthesized using the polyol method,and the control of the synthesis solution pH allowed the formation of Pt NPs of different average sizes,which was confirmed by TEM.The onset potential was more negative for the smallest nanoparticles(1.3 nm)compared to those for the larger ones.Pt/C with a mean particle size of 2.2 nm showed better stability while exhibiting comparable activity to the 1.3 nm particles.As revealed by in situ polarization modulation infrared reflection absorption spectroscopy(PM-IRRAS),the oxidation products included N–H species,azide ions,and nitrate and nitrite compounds.The N–H stretching peak was observed at about 2800 cm^(-1) on the Pt surface and in the bulk of the electrolyte.However,the intensity of peaks corresponding to the reaction products was different on the surface of Pt and in the bulk of the electrolyte.NO_(2)−was mostly observed in the bulk of the electrolyte.In contrast,NO_(3)−was present on the Pt surface.PM-IRRAS demonstrated that the particle size affected the catalytic activity of Pt/C NPs but not their selectivity.In addition,the PM-IRRAS technique allowed,for the first time,distinguishing both symmetric and asymmetric N–O bonds that were not observed previously using IR spectroscopy during ammonia electrooxidation.展开更多
基金the National Nature Science Foundation of China for Excellent Young Scientists Fund(32222058)Fundamental Research Foundation of CAF(CAFYBB2022QB001).
文摘Developing biomass platform compounds into high value-added chemicals is a key step in renewable resource utilization.Herein,we report porous carbon-supported Ni-ZnO nanoparticles catalyst(Ni-ZnO/AC)synthesized via low-temperature coprecipitation,exhibiting excellent performance for the selective hydrogenation of 5-hydroxymethylfurfural(HMF).A linear correlation is first observed between solvent polarity(E_(T)(30))and product selectivity within both polar aprotic and protic solvent classes,suggesting that solvent properties play a vital role in directing reaction pathways.Among these,1,4-dioxane(aprotic)favors the formation of 2,5-bis(hydroxymethyl)furan(BHMF)with 97.5%selectivity,while isopropanol(iPrOH,protic)promotes 2,5-dimethylfuran production with up to 99.5%selectivity.Mechanistic investigations further reveal that beyond polarity,proton-donating ability is critical in facilitating hydrodeoxygenation.iPrOH enables a hydrogen shuttle mechanism where protons assist in hydroxyl group removal,lowering the activation barrier.In contrast,1,4-dioxane,lacking hydrogen bond donors,stabilizes BHMF and hinders further conversion.Density functional theory calculations confirm a lower activation energy in iPrOH(0.60 eV)compared to 1,4-dioxane(1.07 eV).This work offers mechanistic insights and a practical strategy for solvent-mediated control of product selectivity in biomass hydrogenation,highlighting the decisive role of solvent-catalyst-substrate interactions.
基金supported by the Educational and Tech-nological Department of Hunan Province(No.08B063)the Natural Science Foundation of Science and Technology Department of Hunan Government(No.2007GK3060)the Doctor Foundation of Jishou University(No.JSDXKYZZ200648).
文摘The activated carbon-supported TiO2 nanoparticles(TiO2/AC)were prepared by a properly controlled sol-gel method.The effects of activated carbons(AC)support on inactivated properties of TiO2 nanoparticles were evaluated by photocatalytic inactivation experiments of Escherichia coli.The key factors affecting the inactivation effciency were investigated,including electric power of lamp, temperature,and pH values.The results show that the TiO2/AC composites have high inactivation properties of E.coli in compari...
基金This work was financially supported by the Science and Technology project of Jiangsu province(BN2015021,XZ-SZ201819).
文摘As a main oxidizer in solid composite propellants,ammonium perchlorate(AP)plays an important role because its thermal decomposition behavior has a direct influence on the characteristic of solid composite propellants.To improve the performance of solid composite propellant,it is necessary to take measures to modify the thermal decomposition behavior of AP.In recent years,transition metal oxides and carbon-supported transition metal oxides have drawn considerable attention due to their extraordinary catalytic activity.In this review,we highlight strategies to enhance the thermal decomposition of AP by tuning morphology,varying the types of metal ion,and coupling with carbon analogue.The enhanced catalytic performance can be ascribed to synergistic effect,increased surface area,more exposed active sites,and accelerated electron transportation and so on.The mechanism of AP decomposition mixed with catalyst has also been briefly summarized.Finally,a conclusive outlook and possible research directions are suggested to address challenges such as lacking practical application in actual formulation of solid composite propellant and batch manufacturing.
基金supported by the Natural Science Foundation of China(91645115 and 21473003)High-level talents funding project of Hebei(CL201601,E2016100015)science technology research and development guidance program project of Baoding City(No.16ZF027)
文摘Carbon-supported copper catalyst was prepared for the first time in one-step with copper nitrate and corn stalk through calcination under different temperatures. Uniformly dispersed nanoparticles were obtained and were identified to be Cu（0） and Cu（Ⅰ） in XRD patterns. Excellent catalytic activity and selectivity were achieved in the N-arylation of pyrazole under ligand and protection gas free conditions. About90.4% of product yield was achieved with only 0.5 mol% of copper catalyst（Cu-C-300）, which was considerably more efficient than previous reports. XPS results suggested that the N-arylation of pyrazole activity was closely related to the surface Cu（Ⅰ） species.
文摘By evaluating the SEM images,specific surface area,and the catalytic synthesis reaction conditions of an activated carbon-supported p-toluenesulfonic acid catalyst,and comparing the physical and chemical properties,infrared spectra,nuclear magnetic resonance spectra,oxidation stability,thermal stability,hydrolytic stability,and extreme pressure anti-wear performance of the synthesized trihydroxymethylpropyl trioleate with imported reference esters,the feasibility of its application as a substitute was investigated.The results indicated that the activated carbon-supported p-toluenesulfonic acid catalyst exhibited loose porosity,high specific surface area,and high esterification efficiency.When synthesized under optimal conditions,the yield rate of trihydroxymethylpropyl trioleate reached 99.3%,with a simple separation process that did not require additional steps such as neutralization and washing and generated minimal wastewater.The physical and chemical properties of the synthesized trihydroxymethylpropyl trioleate were comparable to those of the reference ester in terms of color,viscosity,viscosity index,flash point,and pour point.Moreover,the peak position and peak height in the infrared and nuclear magnetic carbon spectra were essentially the same.Through comprehensive evaluations and comparisons of various properties,it was determined that the performance of trihydroxymethylpropyl trioleate was comparable to that of the imported reference esters.
基金supported by the National Natural Science Foundation of China(No.51371017)。
文摘Carbon-supported transition metal single atoms are promising oxygen reduction reaction(ORR)electrocatalyst.Since there are many types of carbon supports and transition metals,the accurate prediction of the components with high activity through theoretical calculations can greatly save experimental time and costs.In this work,the ORR catalytic properties of 180 types single-atom catalysts(SACs)composed of the eight representative carbon-based substrates(graphdiyne,C_(2)N,C_(3)N_(4),phthalocyanine,C-coordination graphene,N-coordination graphene,covalent organic frameworks and metal-organic frameworks)and 3d,4d,and 5d transition metal elements are investigated by density functional theory(DFT).The adsorption free energy of OH^(*) is proved a universal descriptor capable of accurately prediction of the ORR catalytic activity.It is found that the oxygen reduction reaction overpotentials of all the researched SACs follow one volcano shape very well with the adsorption free energy of OH^(*).Phthalocyanine,N-coordination graphene and metal-organic frameworks stand out as the promising supports for single metal atom due to the relatively lower overpotentials.Notably,the Co-doped metal-organic frameworks,Ir-doped phthalocyanine,Co-doped N-coordination graphene,Co-doped graphdiyne and Rh-doped phthalocyanine show extremely low overpotentials comparable to that of Pt(111).The study provides a guideline for design and selection of carbon-supported SACs toward oxygen reduction reaction.
基金supported in part by the National Key R&D Program of China(Nos.2020YFA0405800,2022YFA1504104,and 2022YFA1605400)the National Natural Science Foundation of China(Nos.12225508,12322515,U1932201,U2032113,and 22075264)+5 种基金the Youth Innovation Promotion Association of CAS(No.2022457)the Institute of Energy,Hefei Comprehensive National Science Center,University Synergy Innovation Program of Anhui Province(No.GXXT-2020-002)and the CAS Iterdisciplinary Innovation Team.We thank the Shanghai Synchrotron Radiation Facility(BL14W1,BL14B1,and SSRF)the Beijing Synchrotron Radiation Facility(1W1B,4B7A,and BSRF)the Hefei Synchrotron Radiation Facility(Infrared Spectroscopy and Microspectroscopy,MCD-A and MCD-B Soochow Beamline for Energy Materials at NSRL)and the USTC Center for Micro and Nanoscale Research and Fabrication for helps in characterizations.
文摘Breakthroughs in energy storage and conversion devices depend heavily on the exploration of low-cost and high-performance materials.Carbon-supported electrocatalysts with dimensional varieties have recently attracted significant attention due to their strong structural flexibility and easy accessibility.Nevertheless,understanding the connection between their electronic,structural properties,and catalytic performance must remain a top priority.Synchrotron radiation(SR)X-ray absorption spectroscopy(XAS)techniques,including hard XAS and soft XAS,are recognized as efficient and comprehensive platforms for probing the surface,interface,and bulk electronic structure of elements of interest in the materials community.In the past decade,the flourishing development of materials science and advanced characterization technologies have led to a deeper understanding at different temporal,longitudinal,and spatial scales.In this review,we briefly describe the concept of XAS techniques and summarize their recent progress in addressing scientific questions on carbon-supported electrocatalysts through the development of advanced instruments and experimental methods.We then discuss the remaining challenges and potential research directions in nextgeneration materials frontiers,and suggest challenges and perspectives for shedding light on the structure–activity relationship.
基金the Natural Sciences and Engineering Research Council of Canada(NSERC)via CRD Grant No.CRDPJ 522410-17a Discovery Grant from the Canadian Urban Transit Research&Innovation Consortium(CUTRIC)via Project No.160028Ballard Power Systems Inc.via Project No.SRA#077701.
文摘Proton exchange membrane fuel cells are playing an increasing role in postpandemic economic recovery and climate action plans.However,their performance,cost,and durability are significantly related to Pt-based electrocatalysts,hampering their large-scale commercial application.Hence,considerable efforts have been devoted to improving the activity and durability of Pt-based electrocatalysts by controlled synthesis in recent years as an effective method for decreasing Pt use,and consequently,the cost.Therefore,this review article focuses on the synthesis processes of carbon-supported Pt-based electrocatalysts,which significantly affect the nanoparticle size,shape,and dispersion on supports and thus the activity and durability of the prepared electrocatalysts.The reviewed processes include(i)the functionalization of a commercial carbon support for enhanced catalyst-support interaction and additional catalytic effects,(ii)the methods for loading Pt-based electrocatalysts onto a carbon support that impact the manufacturing costs of electrocatalysts,(iii)the preparation of spheri-cal and nonspherical Pt-based electrocatalysts(polyhedrons,nanocages,nanoframes,one-and two-dimensional nanostruc-tures),and(iv)the postsynthesis treatments of supported electrocatalysts.The influences of the supports,key experimental parameters,and postsynthesis treatments on Pt-based electrocatalysts are scrutinized in detail.Future research directions are outlined,including(i)the full exploitation of the potential functionalization of commercial carbon supports,(ii)scaled-up one-pot synthesis of carbon-supported Pt-based electrocatalysts,and(iii)simplification of postsynthesis treatments.One-pot synthesis in aqueous instead of organic reaction systems and the minimal use of organic ligands are preferred to simplify the synthesis and postsynthesis treatment processes and to promote the mass production of commercial carbon-supported Pt-based electrocatalysts.
基金support from the China Postdoctoral Science Foundation(2022M711553).Y.W.would like to acknowledge the support from the National Natural Science Foundation of China(22171132)the Innovation Fund from Nanjing University(020514913419)+5 种基金the Program for Innovative Talents and Entrepreneurs in Jiangsu(020513006012 and 020513006014),and the National Key R&D Program of China(2002YFB3607000).W.Z.would like to acknowledge the support from the National Natural Science Foundation of China(22176086)Natural Science Foundation of Jiangsu Province(BK20210189)State Key Laboratory of Pollution Control and Resource Reuse(PCRR-ZZ-202106)the Fundamental Research Funds for the Central Universities(021114380183,021114380189 and 021114380199)the Research Funds from the Nanjing Science and Technology Innovation Project for Chinese Scholars Studying Abroad(13006003)the Research Funds from Frontiers Science Center for Critical Earth Material Cycling of Nanjing University,and Research Funds for Jiangsu Distinguished Professor.Y.L.would like to thank the support from the Washington State University startup fund.
文摘Non-precious metal single-atom catalysts(NPM-SACs)with unique electronic structures and coordination environments have gained much attention in electrocatalysis owing to their low cost,high atomic utilization,and high performance.NPM-SACs on carbon support(NPM-SACs/CS)are promising because of the carbon substrate with a large surface area,excellent electrical conductivity,and high chemical stability.This review provides an overview of recent developments in NPM-SACs/CS for the electrocatalytic field.First,the state-of-the-art synthesis methods and advanced characterization techniques of NPM-SACs/CS are discussed in detail.Then,the structural adjustment strategy of NPM-SACs/CS for optimizing electrocatalytic performance is introduced concisely.Furthermore,we provide a comprehensive summary of recent advances in developing NPM-SACs/CS for important electrochemical reactions,including carbon dioxide reduction reaction,hydrogen evolution reaction,oxygen evolution reaction,oxygen reduction reaction,and nitrogen reduction reaction.In the end,the existing challenges and future opportunities of NPM-SACs/CS in the electrocatalytic field are highlighted.
基金Acknowledgements This research was supported by the National Natural Science Foundation of China （Grant Nos. 21277010 and 51078013）, Special Research Funding for Public Benefit Industries from National Ministry of Environmental Protection （No. 201209005）, the National Science and Technology Support Program of China （No. 2010BAC66B04）, and Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province （No. AE201003）.
文摘Activated carbon （AC）-supported copper or zinc made from ion exchange resin （IRCu-C and IRZn-C） have an increased metal load of 557.3 mg·g^-1 and 502.8 mg·g^-1 compared to those prepared by the traditional method involving impregnation with AC and copper （II） citrate or zinc citrate solution （LaCu-C and LaZn-C） of 12.9 mg·g^-1 and 46.0 mg·g^-1 respectively. When applied to decompose 2,2＇,4,4＇,5,5＇-hexachlorobiphenyl at 250 ℃, IRCu-C achieved higher activity of 99.0% decomposition efficiency than LaCu-C of 84.7%, IRZn-C of 90.5% and LaZn-C of 62.7%. When the reaction temperature rose to 350 ℃, all the four kinds of reactants can decompose PCB- 153 with efficiency above 90%. Further, X-ray photoelec- tron spectroscopy characterization of IRCu-C before and after the reaction indicated transformation of 19.1% of Cu atoms into Cu^2＋, illustrating that Cu is the active ingredient or electron donor promoting the decomposition of PCB- 153. The mechanism underlying this process differs from a traditional H donor. However, there is no significant change on the surface of IRZn-C before and after the reaction, suggesting that Zn acts as catalyst during the process of PCB-153 decomposition.
基金Supported by the National Key Research and Development Program of China(2017YFE0300302)the National Natural Science Foundation of China(21503199,21406212)Key Project of Applied&Basic Research of Sichuan Province(18YYJC1594)
文摘The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum catalysts(Pt/C/PTFE) with high efficiency as reported previously for LPCE were prepared and comprehensive performance evaluation method is applied to evaluate the separation behaviors of LPCE systematically. Experimental results indicate that the optimum reaction temperature of 60–80℃ and the molar feed ratio G/L of 1.5–2.5 would lead to higher separation efficiencies. As to the packing method, a random packing mode with a packing ratio of hydrophobic catalysts 0.25 is recommended. In addition, thermodynamic analysis corresponds well with experimental results under lower temperature and G/L, while the suppression of kinetic factors should not be neglected when T > 80℃ and G/L > 1.5.
基金financially supported by the National Natural Science Foundation of China(Grant No.51773025)the Natural Science Foundation of Liaoning Province(Materials Joint Foundation,Grant No.20180510027)Dalian science and technology innovation fund(Grant No.019J12GX032)。
文摘Currently,pyrolysis as the most widely used method still has some key issues not well resolved for synthesis of carbon-supported single-atom catalysts(C-SACs),e.g.,the sintering of metal atoms at high temperature as well as the high cost and complicated preparations of precursors.In this report,molten salts are demonstrated to be marvellous medium for preparation of C-SACs by pyrolysis of small molecular precursors(ionic liquid).The ultrastrong polarity on one hand establishes robust interaction with precursor and enables better carbonization,resulting in largely enhanced yield.On the other hand,the aggregation of metal atoms is effectively refrained while no nanoparticle or cluster is formed.By this strategy,a C-SAC with atomically dispersed Fe-N_(4) sites and a high specific area over 2000 m^(2) g^(-1) is obtained,which illustrates high ORR activity in both acid and alkaline media.Moreover,this SAC exhibits superior methanol tolerance and stability after acid soaking at 85℃ for 48 h.It is believed that the molten-salts-assisted pyrolysis can be developed into a routine strategy as it not only can largely simply the synthesis of C-SACs,but also can be extended to prepare other types of SACs.
基金supported by the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(2022QNRC001)the Natural Science Foundation of Tianjin City(23JCZDJC01110)+5 种基金the National Natural Science Foundation of China(51972225 and 52202281)the Tianjin University Science and Technology Innovation Leading Talent Training Programthe Natural Science Foundation of Chongqing(CSTB2023NSCQ-MSX0538)the Natural Science Basic Research Program of Shaanxi(2024JC-YBQN-0073)the Young Talent Fund of Association for Science and Technology in Shaanxi(20230101)the Innovation Capability Support Program of Shaanxi-Science and Technology Innovation Team Project(2025RS-CXTD-024)。
文摘Carbon-supported single-atom catalysts(C-SACs)have been demonstrated as a strategy to promote the reversible conversion reaction of metal sulfide anodes in sodium-ion batteries(SIBs).However,the design principle of promising C-SACs remains lacking for obtaining highly reversible metal sulfide anodes.We designed a phosphorus-doped carbon-supported single-atom Mn catalyst(PC-SAMn)with an asymmetrical dual active center.The sulfiphilic Mn and sodiophilic P active centers adsorb discharged Na 2S through Mn-S d-p and P-Na s-p orbital hybridizations.The asymmetrical dual active center induced the asymmetrical adsorption configuration of Na 2S,which efficiently weakened Na-S bond strength and facilitated the decomposition of Na 2S during charging.As a result,the designed catalyst enables typical MoS_(2) with a record-high compositional reversible degree of 89.61%and a low capacity decay ratio of only 0.18%per 100 cycles during 2000 cycles.The research establishes the“orbital hybridization-molecular structure-catalytic activity”relationship for guiding the design of highly reversible conversion-type materials.
基金This work was supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)Discovery Grant(RGPIN05494).
文摘The ammonia electrooxidation reaction(AmER)has attracted considerable attention due to its potential for hydrogen storage and transportation,as well as its possible application in direct ammonia fuel cells.In the present work,we studied ammonia electrooxidation on carbon-supported Pt/C nanoparticles(NPs)of four average sizes of 1.3,2.2,2.8,and 4.2 nm.Carbon-supported Pt NPs with a 20 wt% metal loading were synthesized using the polyol method,and the control of the synthesis solution pH allowed the formation of Pt NPs of different average sizes,which was confirmed by TEM.The onset potential was more negative for the smallest nanoparticles(1.3 nm)compared to those for the larger ones.Pt/C with a mean particle size of 2.2 nm showed better stability while exhibiting comparable activity to the 1.3 nm particles.As revealed by in situ polarization modulation infrared reflection absorption spectroscopy(PM-IRRAS),the oxidation products included N–H species,azide ions,and nitrate and nitrite compounds.The N–H stretching peak was observed at about 2800 cm^(-1) on the Pt surface and in the bulk of the electrolyte.However,the intensity of peaks corresponding to the reaction products was different on the surface of Pt and in the bulk of the electrolyte.NO_(2)−was mostly observed in the bulk of the electrolyte.In contrast,NO_(3)−was present on the Pt surface.PM-IRRAS demonstrated that the particle size affected the catalytic activity of Pt/C NPs but not their selectivity.In addition,the PM-IRRAS technique allowed,for the first time,distinguishing both symmetric and asymmetric N–O bonds that were not observed previously using IR spectroscopy during ammonia electrooxidation.
