Delafossite CuFeO_(2) is a promising photocathode material for cost-efficiently photoelectrochemical(PEC)water splitting,but the unfavorable conductivity and fast recombination dynamics of photogenerated carriers limi...Delafossite CuFeO_(2) is a promising photocathode material for cost-efficiently photoelectrochemical(PEC)water splitting,but the unfavorable conductivity and fast recombination dynamics of photogenerated carriers limit its PEC activity for water reduction.Here,we developed a heterostructure photocathode consisting of the Cu-doped NiO(Cu:NiO)hole selective layer(HSL)and Ni-doped CuFeO_(2)(Ni:CuFeO_(2))active layer by simply annealing a homogeneous Cu-Fe oxalate layer grown on the Ni film deposited on the fluorine doped tin oxide(FTO)substrate.The obtained heterostructure of Cu:NiO/Ni:CuFeO_(2) with enhanced charge carrier transportability and high-quality interface greatly promotes the separation of photogenerated carriers.Accordingly,the Cu:NiO/Ni:CuFeO_(2) photocathode exhibits a high photocurrent density of~0.9 mA·cm^(-2 )at 0.2 V(vs.reversible hydrogen electrode,RHE),outperforming most of the reported bare CuFeO_(2) photocathodes in the literature.And the photocurrent density can be further improved to 1.2 mA·cm^(-2) after decorating NiSx cocatalyst.展开更多
Fe-N-C materials with atomically dispersed Fe–N_(4) sites could tolerate the poisoning of phosphate,is regarded as the most promising alternative to costly Pt-based catalysts for the oxygen reduction in high temperat...Fe-N-C materials with atomically dispersed Fe–N_(4) sites could tolerate the poisoning of phosphate,is regarded as the most promising alternative to costly Pt-based catalysts for the oxygen reduction in high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs).However,they still face the critical issue of insufficient activity in phosphoric acid.Herein,we demonstrate a P-doping strategy to increase the activity of Fe-N-C catalyst via a feasible one-pot method.X-ray absorption spectroscopy and electron microscopy with atomic resolution indicated that the P atom is bonded with the N in Fe–N_(4) site through C atoms.The as prepared Fe-NCP catalyst shows a half-wave potential of 0.75 V(vs.reversible hydrogen electrode(RHE),0.1 M H_(3)PO_(4)),which is 60 and 40 mV higher than that of Fe-NC and commercial Pt/C catalysts,respectively.More importantly,the Fe-NCP catalyst could deliver a peak power density of 357 mW·cm^(−2)in a high temperature fuel cell(160℃),exceeding the non-noble-metal catalysts ever reported.The enhancement of activity is attributed to the increasing charge density and poisoning tolerance of Fe–N_(4) caused by neighboring P.This work not only promotes the practical application of Fe-N-C materials in HT-PEMFCs,but also provides a feasible P-doping method for regulating the structure of single atom site.展开更多
The thermodynamically favorable electrocatalytic oxidation coupled with hydrogen evolution reaction(HER)is considered as a sustainable and promising technique.Nonetheless,it remains a great challenge due to the lack o...The thermodynamically favorable electrocatalytic oxidation coupled with hydrogen evolution reaction(HER)is considered as a sustainable and promising technique.Nonetheless,it remains a great challenge due to the lack of simple,cheap,highefficient electrocatalysts.Here,we successfully develop a simple and scalable electro-deposition and subsequent phosphorization route to fabricate Ni-doped Co_(2)P(Ni-Co_(2)P)nanosheets catalyst using the in-situ released Ni species from defective Ni foam as metal source.Impressively,the as-synthesized Ni-Co_(2)P catalyst exhibits excellent electrochemical 5-hydroxymethylfurfural oxidation reaction(HOR)performance with>99%2,5-furandicarboxylic acid yield and>97%Faradaic efficiency at an ultralow potential of 1.29 V vs.reversible hydrogen electrode(RHE).Experimental characterization and theoretical calculation reveal that the atomically doped Ni species can enhance the adsorption of reactant and thus lower the reaction energy barriers.By coupling the electrocatalytic HOR with HER,the employed two-electrode system using Ni-Co_(2)P and commercial Ni foam as anode and cathode,respectively,exhibits a low cell voltage of 1.53 V to drive a current density of 10 mA·cm^(−2),which is 90 mV lower than that of pure water splitting.This work provides a facile and efficient approach for the preparation of high-performance earth-abundant electrocatalysts toward the concurrent production of H_(2)and value-added chemicals.展开更多
Solid-waste-based activated carbon(AC)was utilized as a carbon source to synthesize a series of carbon-based functional material RAC-X(X=P and S,where P and S denote phosphoric and sulfuric acids,respectively).The tol...Solid-waste-based activated carbon(AC)was utilized as a carbon source to synthesize a series of carbon-based functional material RAC-X(X=P and S,where P and S denote phosphoric and sulfuric acids,respectively).The toluene adsorption capacities of the regeneration AC(RAC)samples can be significantly improved by adopting the heteroatomic modification strategy.RAC-P and RAC-S have the same specific surface area(1156 m^(2)/g)and similar porous structures.However,they have different toluene adsorption capacities,with 316.22 mg/g for RAC-P and 460.12 mg/g for RAC-S,which are 1.6 and 2.4 times greater than that for RAC.The X-ray photoelectron spectroscopy measurements showed that the increase in the amount ofπ–π^(2)chemical bond over the AC surface results in the improvement of the toluene adsorption performance.The density functional theory results showed that the S-containing functional groups loaded near the defect sites of RAC-S promote toluene adsorption.Moreover,reusability tests showed that RAC-S still retains 86%of its adsorption activity after four consecutive adsorption–desorption experiments.This indicates that the heteroatomic modification method affords excellent toluene adsorption performance and recycling practicability,which not only is beneficial for achieving the rational utilization of solid waste resources but also provides a practical method for the efficient elimination of volatile organic compounds.展开更多
In recent years,the isolated single-atom site(ISAS)catalysts have attracted much attention as they are cost-effective,can achieve 100%atom-utilization efficiency,and often display superior catalytic performance.Here,w...In recent years,the isolated single-atom site(ISAS)catalysts have attracted much attention as they are cost-effective,can achieve 100%atom-utilization efficiency,and often display superior catalytic performance.Here,we developed a biomass-assisted pyrolysis-etching-activation(PEA)strategy to construct ISAS metal decorated on N and B co-doped porous carbon(ISAS M/NBPC,M=Co,Fe,or Ni)catalysts.This PEA strategy can be applied in the universal and large-scale preparation of ISAS catalysts.Interestingly,the ISAS M/NBPC(M=Co,Fe,or Ni)catalysts show multi-functional features and excellent catalytic activities.They can be used to conduct different types of catalytic reactions,such as O-silylation(OSI),oxidative dehydrogenation(ODH),and transfer hydrogenation(THG).In addition,we used the transfer hydrogenation of nitrobenzene as a typical reaction and revealed the difference between ISAS Co/NBPC and ISAS Co/NPC(N-doped porous carbon)catalysts by density functional theory(DFT)calculations,and which showed that the decreased barrier of the ratedetermining step and the low-lying potential energy diagram indicate that the catalytic activity is higher when ISAS Co/NBPC is used than that when ISAS Co/NPC is used.These results demonstrate that the catalytic performance can be effectively improved by adjusting the coordination environment around the ISAS.展开更多
2D transition metal disulfides have emerged as promising Pt-alternative electrocatalysts for hydrogen generation.However,the sluggish water dissociation kinetics and limited active sites hinder their performance in al...2D transition metal disulfides have emerged as promising Pt-alternative electrocatalysts for hydrogen generation.However,the sluggish water dissociation kinetics and limited active sites hinder their performance in alkaline media.Herein,we propose a two-step hydrothermal method to synthesize K intercalation-assisted Codoped MoS_(2) nanoflowers.These nanoflowers exhibit an overpotential of only 67 mV at a current density of 10 mA cm^(-2),which exceeds that of pristine MoS_(2)(143 mV).We demonstrated that the intercalation of K enlarges the interlayer spacing of MoS_(2) nanosheets and facilitates the doping of Co.The incorporation of Co effectively improves the surface charge transfer efficiency of MoS_(2) and accelerates water splitting with an energy barrier of 0.12 eV.This work offers an approach to activate the inert MoS_(2) basal plane by chemical intercalation and atomic doping coengineering.It can be extended to develop other functional materials beyond water splitting.展开更多
Although Fe-Ni combination performs well in transition metal-based oxygen evolution reaction(OER)electrocatalysts,there are lack of clear and general regulations mechanism to fully play the synergistic catalytic effec...Although Fe-Ni combination performs well in transition metal-based oxygen evolution reaction(OER)electrocatalysts,there are lack of clear and general regulations mechanism to fully play the synergistic catalytic effect.Here,we made the utmost of the interaction of Fe–Ni heteroatomic pair to obtain a highly active Fe-Ni(oxy)hydroxide catalytic layer on iron foam(IF)and nickel foam(NF)by in-situ electrochemical deposition and rapid surface reconstruction,which only required 327 and 351 mV overpotential to provide a large current of 1,000 mA·cm^(−2),respectively.The results confirm that the moderate Ni-rich heteroatomic bonding(Ni–O–Fe–O–Ni)formed by adjusting the Ni/Fe ratio on the catalyst surface is important to offer predominant OER performance.Fe is a key component that enhances OER activity of Ni(O)OH,but Fe-rich structural surface formed by Fe–O–Ni–O–Fe bonding is not ideal.Finally,the remarkable oxygen evolution performance of the prepared Ni2Fe(O)OH/IF and FeNi2(O)OH/NF can be chalked up to the optimized electronic structure of Fe–Ni heteroatomic bonding,the efficient gas spillover,the fast electron transport,and nanosheet clusters morphology.In summary,our work suggests a comprehensive regulation mechanism for the construction of efficient Fe-Ni(oxy)hydroxide catalytic layer on inexpensive,stable,and self-supporting metallic material surface.展开更多
In the field of electrolysis of water,the design and synthesis of catalysts over a wide pH range have attracted extensive attentions.In this paper,Co and N are co-introduced into the structural unit of tungsten disulf...In the field of electrolysis of water,the design and synthesis of catalysts over a wide pH range have attracted extensive attentions.In this paper,Co and N are co-introduced into the structural unit of tungsten disulfide(WS_(2)),and the hydrogen evolution reaction(HER)performances of different WS_(2)-based catalysts are theoretically predicted and systematically studied by density functional theory(DFT)calculations.With the guidance of DFT calculations,an evaporation-pyrolysis strategy is applied to prepare Co and N co-doped WS_(2)(Co,N-WS_(2))flower-like nanosheets,which exhibits excellent HER performance over a wide pH range.In addition,the DFT calculations show that the active sites in Co,N-WS_(2) have a good ability of hydrogen adsorption after the introduction of Co and N,suggesting that such a co-doping system will be an ideal catalyst for oxidative dehydrogenation(ODH).The following experiment results indeed evidence that the Co,N-WS_(2) catalyst displays a high activity in the ODH of 1,2,3,4-tetrahydroquinoline(4H-quinoline)and its derivatives.Therefore,this work provides a good example for the rational design and accurate preparation of functional catalysts,which enables it possible to develop other efficient catalysts with multiple functions.展开更多
The signals of 1H NMR and 13 C NMR for benzodiheteropine 1 and its cycloaddtion products 2～5 were assigned by two dimensional NMR techniques. The characteristics of their structures were analyzed and ...The signals of 1H NMR and 13 C NMR for benzodiheteropine 1 and its cycloaddtion products 2～5 were assigned by two dimensional NMR techniques. The characteristics of their structures were analyzed and discussed. The boat conformation of the seven membered heteroatomic ring in these structures was interpreted on the basis of the spectrum of NOESY as well. The coupling constants of relative protons were in accord with above results.展开更多
基金financially supported by the National Key Research and Development Program of China(No.2021YFA1500800)the National Natural Science Foundation of China(Nos.51825204,52072377,521888101 and 51402199)+6 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2020192)the International Partnership Program of Chinese Academy of Sciences(No.174321KYSB20200005)China Postdoctoral Science Foundation(No.2017M621137)Liaoning Revitalization Talents Program(No.XLYC2007193)the Natural Science Foundation of Liaoning Province(Nos.2021-MS-014 and 2021NLTS1210)the University Innovation Talent Foundation of Liaoning Province(No.LR2018074)the State Key Laboratory of Fine Chemicals,Dalian University of Technology(No.KF1708)。
文摘Delafossite CuFeO_(2) is a promising photocathode material for cost-efficiently photoelectrochemical(PEC)water splitting,but the unfavorable conductivity and fast recombination dynamics of photogenerated carriers limit its PEC activity for water reduction.Here,we developed a heterostructure photocathode consisting of the Cu-doped NiO(Cu:NiO)hole selective layer(HSL)and Ni-doped CuFeO_(2)(Ni:CuFeO_(2))active layer by simply annealing a homogeneous Cu-Fe oxalate layer grown on the Ni film deposited on the fluorine doped tin oxide(FTO)substrate.The obtained heterostructure of Cu:NiO/Ni:CuFeO_(2) with enhanced charge carrier transportability and high-quality interface greatly promotes the separation of photogenerated carriers.Accordingly,the Cu:NiO/Ni:CuFeO_(2) photocathode exhibits a high photocurrent density of~0.9 mA·cm^(-2 )at 0.2 V(vs.reversible hydrogen electrode,RHE),outperforming most of the reported bare CuFeO_(2) photocathodes in the literature.And the photocurrent density can be further improved to 1.2 mA·cm^(-2) after decorating NiSx cocatalyst.
基金the National Key Research and Development Program of China(No.2018YFA0702002)the Beijing Natural Science Foundation(No.Z210016)the National Natural Science Foundation of China(No.21935001)。
文摘Fe-N-C materials with atomically dispersed Fe–N_(4) sites could tolerate the poisoning of phosphate,is regarded as the most promising alternative to costly Pt-based catalysts for the oxygen reduction in high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs).However,they still face the critical issue of insufficient activity in phosphoric acid.Herein,we demonstrate a P-doping strategy to increase the activity of Fe-N-C catalyst via a feasible one-pot method.X-ray absorption spectroscopy and electron microscopy with atomic resolution indicated that the P atom is bonded with the N in Fe–N_(4) site through C atoms.The as prepared Fe-NCP catalyst shows a half-wave potential of 0.75 V(vs.reversible hydrogen electrode(RHE),0.1 M H_(3)PO_(4)),which is 60 and 40 mV higher than that of Fe-NC and commercial Pt/C catalysts,respectively.More importantly,the Fe-NCP catalyst could deliver a peak power density of 357 mW·cm^(−2)in a high temperature fuel cell(160℃),exceeding the non-noble-metal catalysts ever reported.The enhancement of activity is attributed to the increasing charge density and poisoning tolerance of Fe–N_(4) caused by neighboring P.This work not only promotes the practical application of Fe-N-C materials in HT-PEMFCs,but also provides a feasible P-doping method for regulating the structure of single atom site.
基金the National Key Research and Development(R&D)Program of China(No.2020YFA0406103)the National Natural Science Foundation of China(NSFC)(Nos.21725102,51902311,22122506,91961106,22075267,and 21803002)+5 种基金Strategic Priority Research Program of the CAS(No.XDPB14)Anhui Provincial Natural Science Foundation(No.2008085J05)Youth Innovation Promotion Association of CAS(No.2019444)Open Funding Project of National Key Laboratory of Human Factors Engineering(No.SYFD062010K)Users with Excellence Program of Hefei Science Center CAS(No.2020HSCUE003)Fundamental Research Funds for the Central Universities(No.WK2060000039).
文摘The thermodynamically favorable electrocatalytic oxidation coupled with hydrogen evolution reaction(HER)is considered as a sustainable and promising technique.Nonetheless,it remains a great challenge due to the lack of simple,cheap,highefficient electrocatalysts.Here,we successfully develop a simple and scalable electro-deposition and subsequent phosphorization route to fabricate Ni-doped Co_(2)P(Ni-Co_(2)P)nanosheets catalyst using the in-situ released Ni species from defective Ni foam as metal source.Impressively,the as-synthesized Ni-Co_(2)P catalyst exhibits excellent electrochemical 5-hydroxymethylfurfural oxidation reaction(HOR)performance with>99%2,5-furandicarboxylic acid yield and>97%Faradaic efficiency at an ultralow potential of 1.29 V vs.reversible hydrogen electrode(RHE).Experimental characterization and theoretical calculation reveal that the atomically doped Ni species can enhance the adsorption of reactant and thus lower the reaction energy barriers.By coupling the electrocatalytic HOR with HER,the employed two-electrode system using Ni-Co_(2)P and commercial Ni foam as anode and cathode,respectively,exhibits a low cell voltage of 1.53 V to drive a current density of 10 mA·cm^(−2),which is 90 mV lower than that of pure water splitting.This work provides a facile and efficient approach for the preparation of high-performance earth-abundant electrocatalysts toward the concurrent production of H_(2)and value-added chemicals.
基金National key R&D Program of China(No.2022YFC3701903)natural science foundation of Shanxi Province(No.202203021211178)National Natural Science Foundation of China(51901209)for financial support.
文摘Solid-waste-based activated carbon(AC)was utilized as a carbon source to synthesize a series of carbon-based functional material RAC-X(X=P and S,where P and S denote phosphoric and sulfuric acids,respectively).The toluene adsorption capacities of the regeneration AC(RAC)samples can be significantly improved by adopting the heteroatomic modification strategy.RAC-P and RAC-S have the same specific surface area(1156 m^(2)/g)and similar porous structures.However,they have different toluene adsorption capacities,with 316.22 mg/g for RAC-P and 460.12 mg/g for RAC-S,which are 1.6 and 2.4 times greater than that for RAC.The X-ray photoelectron spectroscopy measurements showed that the increase in the amount ofπ–π^(2)chemical bond over the AC surface results in the improvement of the toluene adsorption performance.The density functional theory results showed that the S-containing functional groups loaded near the defect sites of RAC-S promote toluene adsorption.Moreover,reusability tests showed that RAC-S still retains 86%of its adsorption activity after four consecutive adsorption–desorption experiments.This indicates that the heteroatomic modification method affords excellent toluene adsorption performance and recycling practicability,which not only is beneficial for achieving the rational utilization of solid waste resources but also provides a practical method for the efficient elimination of volatile organic compounds.
基金This work was supported by the National Natural Science Foundation of China(Nos.21771003,51902003,21901007,22002085,and 21501004)the University Synergy Innovation Program of Anhui Province(No.GXXT-2021-020)+3 种基金the Anhui Province Natural Science Foundation(Nos.2008085QB53 and 2008085QB83)the Natural Science Research Project of Anhui Province Education Department(No.KJ2019A0581)the Open Project of Key Laboratory of Metallurgical Emission Reduction&Resources Recycling of Ministry of Education(No.JKF21-03)the Open Foundation of Anhui Laboratory of Clean Catalytic Engineering(No.LCCE-01).
文摘In recent years,the isolated single-atom site(ISAS)catalysts have attracted much attention as they are cost-effective,can achieve 100%atom-utilization efficiency,and often display superior catalytic performance.Here,we developed a biomass-assisted pyrolysis-etching-activation(PEA)strategy to construct ISAS metal decorated on N and B co-doped porous carbon(ISAS M/NBPC,M=Co,Fe,or Ni)catalysts.This PEA strategy can be applied in the universal and large-scale preparation of ISAS catalysts.Interestingly,the ISAS M/NBPC(M=Co,Fe,or Ni)catalysts show multi-functional features and excellent catalytic activities.They can be used to conduct different types of catalytic reactions,such as O-silylation(OSI),oxidative dehydrogenation(ODH),and transfer hydrogenation(THG).In addition,we used the transfer hydrogenation of nitrobenzene as a typical reaction and revealed the difference between ISAS Co/NBPC and ISAS Co/NPC(N-doped porous carbon)catalysts by density functional theory(DFT)calculations,and which showed that the decreased barrier of the ratedetermining step and the low-lying potential energy diagram indicate that the catalytic activity is higher when ISAS Co/NBPC is used than that when ISAS Co/NPC is used.These results demonstrate that the catalytic performance can be effectively improved by adjusting the coordination environment around the ISAS.
基金the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(2022C01151)the National Natural Science Foundation of China(21802120 and 21872121).
文摘2D transition metal disulfides have emerged as promising Pt-alternative electrocatalysts for hydrogen generation.However,the sluggish water dissociation kinetics and limited active sites hinder their performance in alkaline media.Herein,we propose a two-step hydrothermal method to synthesize K intercalation-assisted Codoped MoS_(2) nanoflowers.These nanoflowers exhibit an overpotential of only 67 mV at a current density of 10 mA cm^(-2),which exceeds that of pristine MoS_(2)(143 mV).We demonstrated that the intercalation of K enlarges the interlayer spacing of MoS_(2) nanosheets and facilitates the doping of Co.The incorporation of Co effectively improves the surface charge transfer efficiency of MoS_(2) and accelerates water splitting with an energy barrier of 0.12 eV.This work offers an approach to activate the inert MoS_(2) basal plane by chemical intercalation and atomic doping coengineering.It can be extended to develop other functional materials beyond water splitting.
基金the National Natural Science Foundation of China(No.52174283)the Shandong Provincial Natural Science Foundation(No.ZR2020MB044)Postgraduate Innovation Engineering Project of China University of Petroleum(East China)(No.YCX2021147).
文摘Although Fe-Ni combination performs well in transition metal-based oxygen evolution reaction(OER)electrocatalysts,there are lack of clear and general regulations mechanism to fully play the synergistic catalytic effect.Here,we made the utmost of the interaction of Fe–Ni heteroatomic pair to obtain a highly active Fe-Ni(oxy)hydroxide catalytic layer on iron foam(IF)and nickel foam(NF)by in-situ electrochemical deposition and rapid surface reconstruction,which only required 327 and 351 mV overpotential to provide a large current of 1,000 mA·cm^(−2),respectively.The results confirm that the moderate Ni-rich heteroatomic bonding(Ni–O–Fe–O–Ni)formed by adjusting the Ni/Fe ratio on the catalyst surface is important to offer predominant OER performance.Fe is a key component that enhances OER activity of Ni(O)OH,but Fe-rich structural surface formed by Fe–O–Ni–O–Fe bonding is not ideal.Finally,the remarkable oxygen evolution performance of the prepared Ni2Fe(O)OH/IF and FeNi2(O)OH/NF can be chalked up to the optimized electronic structure of Fe–Ni heteroatomic bonding,the efficient gas spillover,the fast electron transport,and nanosheet clusters morphology.In summary,our work suggests a comprehensive regulation mechanism for the construction of efficient Fe-Ni(oxy)hydroxide catalytic layer on inexpensive,stable,and self-supporting metallic material surface.
基金the National Natural Science Foundation of China(Nos.21771003,51902003,and 21501004)the University Synergy Innovation Program of Anhui Province(No.GXXT-2021-020)+1 种基金the Natural Science Foundation of Anhui Province(No.2008085QB53)the Natural Science Research Project of Anhui Province Education Department(No.KJ2019A0581).
文摘In the field of electrolysis of water,the design and synthesis of catalysts over a wide pH range have attracted extensive attentions.In this paper,Co and N are co-introduced into the structural unit of tungsten disulfide(WS_(2)),and the hydrogen evolution reaction(HER)performances of different WS_(2)-based catalysts are theoretically predicted and systematically studied by density functional theory(DFT)calculations.With the guidance of DFT calculations,an evaporation-pyrolysis strategy is applied to prepare Co and N co-doped WS_(2)(Co,N-WS_(2))flower-like nanosheets,which exhibits excellent HER performance over a wide pH range.In addition,the DFT calculations show that the active sites in Co,N-WS_(2) have a good ability of hydrogen adsorption after the introduction of Co and N,suggesting that such a co-doping system will be an ideal catalyst for oxidative dehydrogenation(ODH).The following experiment results indeed evidence that the Co,N-WS_(2) catalyst displays a high activity in the ODH of 1,2,3,4-tetrahydroquinoline(4H-quinoline)and its derivatives.Therefore,this work provides a good example for the rational design and accurate preparation of functional catalysts,which enables it possible to develop other efficient catalysts with multiple functions.
文摘The signals of 1H NMR and 13 C NMR for benzodiheteropine 1 and its cycloaddtion products 2～5 were assigned by two dimensional NMR techniques. The characteristics of their structures were analyzed and discussed. The boat conformation of the seven membered heteroatomic ring in these structures was interpreted on the basis of the spectrum of NOESY as well. The coupling constants of relative protons were in accord with above results.
