Light-metalloid-atom-doped Pd interstitial nanoalloy is promising candidate for electrocatalysis because of the favorable electronic effect.Herein,an innovative method was developed to synthesize C-doped Pd interstiti...Light-metalloid-atom-doped Pd interstitial nanoalloy is promising candidate for electrocatalysis because of the favorable electronic effect.Herein,an innovative method was developed to synthesize C-doped Pd interstitial nanoalloy using palladium acetate both as metal precursor and C dopant.Elaborate characterizations demonstrated that C atoms were successfully doped into the Pd lattice via self-catalytic decomposition of acetate ions.The as-synthesized C-doped Pd catalysts showed excellent activity and durable stability for formic acid electrooxidation.The mass activity and specific activity at 0.6 V of C-doped Pd were approximately 2.59 A/mg and 3.50 mA cm^(-2),i.e.,2.4 and 2.6 times of Pd,respectively.DFT calculations revealed that interstitial doping with C atoms induced differentiation of Pd sites.The strong noncovalent interaction between the Pd sites and the key intermediates endowed Pd with high-selectivity to direct routes and enhanced CO tolerance.This work presents a sites-differentiation strategy for metallic catalysts to improve the electrocatalysis.展开更多
The rational design of efficient bimetallic nanoparticle(NP)catalysts is challenging due to the lack of theoretical understanding of active components and insights into the mechanisms of a specific reaction.Here,we re...The rational design of efficient bimetallic nanoparticle(NP)catalysts is challenging due to the lack of theoretical understanding of active components and insights into the mechanisms of a specific reaction.Here,we report the rational design of nanoreactors comprising hollow carbon sphere-confined PtNi bimetallic NPs(PtNi@HCS)as highly efficient catalysts for hydrogen generation via ammonia borane hydrolysis in water.Using both density functional theory calculations and molecular dynamics simulations,the effects of an active PtNi combination and the critical synergistic role of a hollow carbon shell on the molecule diffusion adsorption behaviors are explored.Kinetic isotope effects and theoretical calculations allow the clarification of the mechanism,with oxidative addition of an O-H bond of water to the catalyst surface being the rate-determining step.The remarkable catalytic activity of the PtNi@HCS nanoreactor was also utilized for successful tandem catalytic hydrogenation reactions,using in situ-generated H_(2) from ammonia borane with high efficiency.The concerted design,theoretical calculations,and experimental work presented here shed light on the rational elaboration of efficient nanocatalysts and contribute to the establishment of a circular carbon economy using green hydrogen.展开更多
Ni^(2+)/Cu^(2+)/SO_(4)^(2-)/polyvinyl alcohol precursor fibers with uniform diameters were prepared through electrospinning.Nickel-based composite nanoalloys containing Ni,Cu,and S were prepared through heat treatment...Ni^(2+)/Cu^(2+)/SO_(4)^(2-)/polyvinyl alcohol precursor fibers with uniform diameters were prepared through electrospinning.Nickel-based composite nanoalloys containing Ni,Cu,and S were prepared through heat treatment in an Ar atmosphere.The experimental results show that the main components of the prepared nanoalloys are NiCu,Ni_(3)S_(2),Ni,and C.The nanoalloys exhibit fine grain sizes about 200-500 nm,which can increase with increasing heat treatment temperature.Electrochemical test results show that the nickel sulfidemodified NiCu nanoalloy composites exhibit excellent oxygen evolution reaction properties,and the oxygen evolution reaction properties gradually improve with the increasing heat treatment temperature.The sample prepared at 1 000℃ for 40 min show a low overpotential of 423 mV and a small Tafel slope of 134 mV·dec^(-1) at a current density of 10 mA·cm^(-2).展开更多
The development of active yet stable catalysts for oxygen reduction reaction(ORR)is still a major issue for the extensive permeation of fuel cells into everyday technology.While nanostructured Pt catalysts are to date...The development of active yet stable catalysts for oxygen reduction reaction(ORR)is still a major issue for the extensive permeation of fuel cells into everyday technology.While nanostructured Pt catalysts are to date the best available systems in terms of activity,the same is not true for stability,particularly under operating conditions.In this work,Pt_(Х)Y alloy nanoparticles are proposed as active and durable electrocatalysts for ORR.Pt_(Х)Y nanoalloys are synthesized and further optimized by laser ablation in liquid followed by laser fragmentation in liquid.The novel integrated laser-assisted methodology succeeded in producing Pt_(Х)Y nanoparticles with the ideal size(<10 nm)of commercial Pt catalysts,yet resulting remarkably more active with E_(1/2)=0.943 V vs.RHE,specific activity=1095μA cm^(-2) and mass activity>1000 A g^(-1).At the same time,the nanoalloys are embedded in a fine Pt oxide matrix,which allows a greater stability of the catalyst than the commercial Pt reference,as directly verified on a gas diffusion electrode.展开更多
Preciously tuning the surface composition of noble metal nanoparticles with the particle size of only 2 nm or less by alloying with other metals represents a powerful strategy to boost their electrocatalytic selectivi...Preciously tuning the surface composition of noble metal nanoparticles with the particle size of only 2 nm or less by alloying with other metals represents a powerful strategy to boost their electrocatalytic selectivity.However,the synthesis of ultrafine nanoalloys and tuning their surface composition remain challenging.In this report,ultrafine CuPd nanoalloys with the particle size of ca.2 nm are synthesized based on the galvanic replacement reaction between presynthesized Cu nanoparticles and Pd2+precursors,and the tuning of their surface compositions is also achieved by changing the atom ratios of Cu/Pd.For the electrocatalytic reduction of CO2,Cu5Pd5 nanoalloys show the CO Faradaic efficiency(FE)of 88%at−0.87 V,and the corresponding mass activity reaches 56 A/g that is much higher than those of Cu8Pd2 nanoalloys,Cu3Pd7 nanoalloys and most of previously reported catalysts.Density functional theory uncovers that with the increase of Pd on the surface of the ultrafine CuPd nanoalloys,the adsorbed energy of both of intermediate COOH*and CO*to the Pd sites is strengthened.The Cu5Pd5 nanoalloys with the optimal surface composition better balance the adsorption of COOH*and desorption of CO*,achieving the highest selectivity and activity.The difficult liberation of absorbed CO*on the surface of Cu3Pd7 nanoalloys provides carbon source to favor the production of ethylene,endowing the Cu3Pd7 nanoalloys with the highest selectivity for ethylene among these ultrafine CuPd nanoalloys.展开更多
Catalytic conversion of CO_(2) to high-value products is a crucial method to achieve targets of carbon dioxide emissions peak and carbon neutralization.However,realizing a controllable product distribution in a single...Catalytic conversion of CO_(2) to high-value products is a crucial method to achieve targets of carbon dioxide emissions peak and carbon neutralization.However,realizing a controllable product distribution in a single CO_(2) hydrogenation process is of great challenge.Herein,we prepared the CuFe nanoalloy catalyst that directly transforms CO_(2) to alkanes using physical sputtering method in mild condition.The characteristic results show that the proximity between Cu and Fe is the crucial factor to tunable products among the different catalysts.The formation of unique coordination of FeCu4 nanoalloys from high-energy sputtering process provides close interaction between Cu and Fe,which is favorable to formation of low carbon paraffin,however,a distant proximity and weak interaction will increase the selectivity of olefins and alcohols.This work provides a general strategy for tuning target chemicals and enriches the viewpoints in CO_(2) hydrogenation.展开更多
The classical molecular dynamics simulations in canonical NVT ensemble conditions are used to investigate the melting transition in different heating rates of Pt-Ag-Au ternary nanoalloys.In order to obtain the initial...The classical molecular dynamics simulations in canonical NVT ensemble conditions are used to investigate the melting transition in different heating rates of Pt-Ag-Au ternary nanoalloys.In order to obtain the initial configurations used in the molecular dynamics simulations,optimizing the chemical ordering of Pt_(13)AgnAu_(42−n)(n=0-42)ternary nanoalloys was performed using the Basin-Hopping algorithm which would not allow changes in the icosahedron structure.The Gupta many-body potential was used to model interatomic interactions in both molecular dynamics simulations and optimization simulations.The melting transitions of selected Pt-Ag-Au nanoalloys were explored using caloric curves and Lindemann parameters.There have been two identified types of melting mechanisms,one includes sudden jump behavior in the caloric curve and the other is an isomerization while melting transition.The temperature range in which the isomerization takes place depends on the heating rate value.展开更多
In this study,truncated octahedron(TO)structure is selected for further analysis and we focus on 38-atom Pd-Pt-Ag trimetallic nanoalloys.The best chemical ordering structures of PdnAg32-nPt6 trimetallic nanoalloys are...In this study,truncated octahedron(TO)structure is selected for further analysis and we focus on 38-atom Pd-Pt-Ag trimetallic nanoalloys.The best chemical ordering structures of PdnAg32-nPt6 trimetallic nanoalloys are obtained at Gupta level.The structures with the lowest energy at Gupta level are then re-optimized by density functional theory(DFT)relaxations and DFT results confirm the Gupta level calculations with small shifts on bond lengths indicating TO structure is favorable for 38-atom of PdnAg32-nPt6 trimetallic nanoalloys.The DFT excess energy analysis shows that Pd8Ag24Pt6 composition has the lowest excess energy value in common with excess energy analysis at Gupta level.In Pd8Ag24Pt6 composition,eight Pd atoms are central sites of 8(111)hexagonal facets of TO,24 Ag atoms locate on surface,and 6 Pt atoms locate at the core of the structure.It is also obtained that all of the compositions except Pd18Ag14Pt6 and Pd20Ag12Pt6 exhibit a octahedral Pt core.Besides,it is observed that there is a clear tendency for Ag atoms to segregate to the surface and also Pt atoms prefer to locate at core due to order parameter(R)variations.展开更多
Oxygen reduction reaction over Pt-based catalyst is one of the most significant cathode reactions in fuel cells.However,low reserves and high price of Pt have motivated researchers worldwide seeking enhanced utilizati...Oxygen reduction reaction over Pt-based catalyst is one of the most significant cathode reactions in fuel cells.However,low reserves and high price of Pt have motivated researchers worldwide seeking enhanced utilization efficiency and durability by doping non-noble metals to form Pt-based alloy catalysts.Alloying Pt with Co has been recognized as one of the most effective approaches to achieve this goal.PtCo bimetal combination is one of the most promising candidates to synthesize highly efficient catalysts for oxygen reduction reaction(ORR)applications,owing to its relatively more suitable oxygen binding energy for four-electron transfer reactions.Recently,impressive strategies have been developed to fabricate more active and stable PtCo-based multimetallic alloys with tailorable size and morphology.This paper aims to summarize the most recent highlights on the study of the relationship between preparation strategies,morphologies,electroactivities of the PtCo-based catalyst at atomic level and further the relevant reaction mechanism.The challenges and opportunities on the further development of electrocatalysts for fuel cells are included to provide reference for the practical application.展开更多
Mixed metal oxide(MMO) represents a critical class of materials that can allow for obtaining a dynamic interface between its components:reduced metal and its metal oxide counterpart during an electrocatalytic reaction...Mixed metal oxide(MMO) represents a critical class of materials that can allow for obtaining a dynamic interface between its components:reduced metal and its metal oxide counterpart during an electrocatalytic reaction.Here,a synthetic method utilizing a MOF-derived micro/mesoporous carbon as a template to prepare sub-2 nm MMO catalysts for CO_(2) electro reduction is reported.Starting from the zeolite imidazolate framework(ZIF-8),the pyrolyzed derivatives were used to synthesize sub-2 nm Pd-Ni MMO with different compositions.The Ni-rich(Pd_(20)-Ni_(80)/ZC) catalyst exhibits unexpectedly superior performance for CO production with an improved Faradaic efficiency(FE) of 95.3% at the current density of 200 mA cm^(-2) at-0.56 V vs.reversible hydrogen electrode(RHE) compared to other Pd-Ni compositions.X-ray photoelectron spectroscopy(XPS) analysis confirms the presence of Ni^(2+) and Pd^(2+) in all compositions,demonstrating the presence of MMO.Density functional theory(DFT) calculation reveals that the lower CO binding energy on the surface of the Pd_(20)-Ni_(80) cluster eases CO desorption,thus increasing its production.This work provides a general synthetic strategy for MMO electrocatalysts and can pave a new way for screening multimetallic catalysts with a dynamic electrochemical interface.展开更多
基金the financial support from the National Natural Science Foundation of China(51904191)the Overseas High-level Talents Foundation of Shenzhen。
文摘Light-metalloid-atom-doped Pd interstitial nanoalloy is promising candidate for electrocatalysis because of the favorable electronic effect.Herein,an innovative method was developed to synthesize C-doped Pd interstitial nanoalloy using palladium acetate both as metal precursor and C dopant.Elaborate characterizations demonstrated that C atoms were successfully doped into the Pd lattice via self-catalytic decomposition of acetate ions.The as-synthesized C-doped Pd catalysts showed excellent activity and durable stability for formic acid electrooxidation.The mass activity and specific activity at 0.6 V of C-doped Pd were approximately 2.59 A/mg and 3.50 mA cm^(-2),i.e.,2.4 and 2.6 times of Pd,respectively.DFT calculations revealed that interstitial doping with C atoms induced differentiation of Pd sites.The strong noncovalent interaction between the Pd sites and the key intermediates endowed Pd with high-selectivity to direct routes and enhanced CO tolerance.This work presents a sites-differentiation strategy for metallic catalysts to improve the electrocatalysis.
基金Financial support was received from the National Key R&D Program of China (2021YFC2902505)the start-up funding by Beijing University of Technology (Changlong Wang)。
文摘The rational design of efficient bimetallic nanoparticle(NP)catalysts is challenging due to the lack of theoretical understanding of active components and insights into the mechanisms of a specific reaction.Here,we report the rational design of nanoreactors comprising hollow carbon sphere-confined PtNi bimetallic NPs(PtNi@HCS)as highly efficient catalysts for hydrogen generation via ammonia borane hydrolysis in water.Using both density functional theory calculations and molecular dynamics simulations,the effects of an active PtNi combination and the critical synergistic role of a hollow carbon shell on the molecule diffusion adsorption behaviors are explored.Kinetic isotope effects and theoretical calculations allow the clarification of the mechanism,with oxidative addition of an O-H bond of water to the catalyst surface being the rate-determining step.The remarkable catalytic activity of the PtNi@HCS nanoreactor was also utilized for successful tandem catalytic hydrogenation reactions,using in situ-generated H_(2) from ammonia borane with high efficiency.The concerted design,theoretical calculations,and experimental work presented here shed light on the rational elaboration of efficient nanocatalysts and contribute to the establishment of a circular carbon economy using green hydrogen.
基金Funded by the Doctoral Fund of Chengdu University(No.2081919131)the Sichuan Science and Technology Program(No.2023YFG0229)。
文摘Ni^(2+)/Cu^(2+)/SO_(4)^(2-)/polyvinyl alcohol precursor fibers with uniform diameters were prepared through electrospinning.Nickel-based composite nanoalloys containing Ni,Cu,and S were prepared through heat treatment in an Ar atmosphere.The experimental results show that the main components of the prepared nanoalloys are NiCu,Ni_(3)S_(2),Ni,and C.The nanoalloys exhibit fine grain sizes about 200-500 nm,which can increase with increasing heat treatment temperature.Electrochemical test results show that the nickel sulfidemodified NiCu nanoalloy composites exhibit excellent oxygen evolution reaction properties,and the oxygen evolution reaction properties gradually improve with the increasing heat treatment temperature.The sample prepared at 1 000℃ for 40 min show a low overpotential of 423 mV and a small Tafel slope of 134 mV·dec^(-1) at a current density of 10 mA·cm^(-2).
基金the P-DISC Grant PROMETEO(project number:P-DiSC#03NExuS_BIRD2021-UNIPD)DYNAMO(project number:P-P-DiSC#01BIRD2020-UNIPD)the financial support of the Fellowship in Applied Electrochemistry 2020。
文摘The development of active yet stable catalysts for oxygen reduction reaction(ORR)is still a major issue for the extensive permeation of fuel cells into everyday technology.While nanostructured Pt catalysts are to date the best available systems in terms of activity,the same is not true for stability,particularly under operating conditions.In this work,Pt_(Х)Y alloy nanoparticles are proposed as active and durable electrocatalysts for ORR.Pt_(Х)Y nanoalloys are synthesized and further optimized by laser ablation in liquid followed by laser fragmentation in liquid.The novel integrated laser-assisted methodology succeeded in producing Pt_(Х)Y nanoparticles with the ideal size(<10 nm)of commercial Pt catalysts,yet resulting remarkably more active with E_(1/2)=0.943 V vs.RHE,specific activity=1095μA cm^(-2) and mass activity>1000 A g^(-1).At the same time,the nanoalloys are embedded in a fine Pt oxide matrix,which allows a greater stability of the catalyst than the commercial Pt reference,as directly verified on a gas diffusion electrode.
基金National Natural Science Foundation of China,Grant/Award Numbers:21573240,21706265,21922813The would like to acknowledge the support provided by the National Natural Science Foundation of China(Grant no.:21573240 and 21706265)+2 种基金the Center for Mesoscience,Institute of Process Engineering,Chinese Academy of Sciences(MPCS-2017-A-02)State Key Laboratory of Multiphase Complex Systems(MPCS-2019-A-09)National Science Fund for Excellent Young Scholars(21922813).
文摘Preciously tuning the surface composition of noble metal nanoparticles with the particle size of only 2 nm or less by alloying with other metals represents a powerful strategy to boost their electrocatalytic selectivity.However,the synthesis of ultrafine nanoalloys and tuning their surface composition remain challenging.In this report,ultrafine CuPd nanoalloys with the particle size of ca.2 nm are synthesized based on the galvanic replacement reaction between presynthesized Cu nanoparticles and Pd2+precursors,and the tuning of their surface compositions is also achieved by changing the atom ratios of Cu/Pd.For the electrocatalytic reduction of CO2,Cu5Pd5 nanoalloys show the CO Faradaic efficiency(FE)of 88%at−0.87 V,and the corresponding mass activity reaches 56 A/g that is much higher than those of Cu8Pd2 nanoalloys,Cu3Pd7 nanoalloys and most of previously reported catalysts.Density functional theory uncovers that with the increase of Pd on the surface of the ultrafine CuPd nanoalloys,the adsorbed energy of both of intermediate COOH*and CO*to the Pd sites is strengthened.The Cu5Pd5 nanoalloys with the optimal surface composition better balance the adsorption of COOH*and desorption of CO*,achieving the highest selectivity and activity.The difficult liberation of absorbed CO*on the surface of Cu3Pd7 nanoalloys provides carbon source to favor the production of ethylene,endowing the Cu3Pd7 nanoalloys with the highest selectivity for ethylene among these ultrafine CuPd nanoalloys.
基金the support of the“Transformational Technologies for Clean Energy and Demonstration”,Strategic Priority Research Program of the Chinese Academy of Sciences(XDA 21090203)the National Natural Science Foundation of China(22078315,22172169)+2 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(2018214,2020189)the Liaoning Revitalization Talents Program(XLYC1907066)the Liaoning Bai Qian Wan Talents Program and DICP(Grant:DICP I202012)。
文摘Catalytic conversion of CO_(2) to high-value products is a crucial method to achieve targets of carbon dioxide emissions peak and carbon neutralization.However,realizing a controllable product distribution in a single CO_(2) hydrogenation process is of great challenge.Herein,we prepared the CuFe nanoalloy catalyst that directly transforms CO_(2) to alkanes using physical sputtering method in mild condition.The characteristic results show that the proximity between Cu and Fe is the crucial factor to tunable products among the different catalysts.The formation of unique coordination of FeCu4 nanoalloys from high-energy sputtering process provides close interaction between Cu and Fe,which is favorable to formation of low carbon paraffin,however,a distant proximity and weak interaction will increase the selectivity of olefins and alcohols.This work provides a general strategy for tuning target chemicals and enriches the viewpoints in CO_(2) hydrogenation.
文摘The classical molecular dynamics simulations in canonical NVT ensemble conditions are used to investigate the melting transition in different heating rates of Pt-Ag-Au ternary nanoalloys.In order to obtain the initial configurations used in the molecular dynamics simulations,optimizing the chemical ordering of Pt_(13)AgnAu_(42−n)(n=0-42)ternary nanoalloys was performed using the Basin-Hopping algorithm which would not allow changes in the icosahedron structure.The Gupta many-body potential was used to model interatomic interactions in both molecular dynamics simulations and optimization simulations.The melting transitions of selected Pt-Ag-Au nanoalloys were explored using caloric curves and Lindemann parameters.There have been two identified types of melting mechanisms,one includes sudden jump behavior in the caloric curve and the other is an isomerization while melting transition.The temperature range in which the isomerization takes place depends on the heating rate value.
文摘In this study,truncated octahedron(TO)structure is selected for further analysis and we focus on 38-atom Pd-Pt-Ag trimetallic nanoalloys.The best chemical ordering structures of PdnAg32-nPt6 trimetallic nanoalloys are obtained at Gupta level.The structures with the lowest energy at Gupta level are then re-optimized by density functional theory(DFT)relaxations and DFT results confirm the Gupta level calculations with small shifts on bond lengths indicating TO structure is favorable for 38-atom of PdnAg32-nPt6 trimetallic nanoalloys.The DFT excess energy analysis shows that Pd8Ag24Pt6 composition has the lowest excess energy value in common with excess energy analysis at Gupta level.In Pd8Ag24Pt6 composition,eight Pd atoms are central sites of 8(111)hexagonal facets of TO,24 Ag atoms locate on surface,and 6 Pt atoms locate at the core of the structure.It is also obtained that all of the compositions except Pd18Ag14Pt6 and Pd20Ag12Pt6 exhibit a octahedral Pt core.Besides,it is observed that there is a clear tendency for Ag atoms to segregate to the surface and also Pt atoms prefer to locate at core due to order parameter(R)variations.
基金supported by the National Natural Science Foundation of China(22008262)Natural Science Foundation of Shandong Province(ZR2020QB187).
文摘Oxygen reduction reaction over Pt-based catalyst is one of the most significant cathode reactions in fuel cells.However,low reserves and high price of Pt have motivated researchers worldwide seeking enhanced utilization efficiency and durability by doping non-noble metals to form Pt-based alloy catalysts.Alloying Pt with Co has been recognized as one of the most effective approaches to achieve this goal.PtCo bimetal combination is one of the most promising candidates to synthesize highly efficient catalysts for oxygen reduction reaction(ORR)applications,owing to its relatively more suitable oxygen binding energy for four-electron transfer reactions.Recently,impressive strategies have been developed to fabricate more active and stable PtCo-based multimetallic alloys with tailorable size and morphology.This paper aims to summarize the most recent highlights on the study of the relationship between preparation strategies,morphologies,electroactivities of the PtCo-based catalyst at atomic level and further the relevant reaction mechanism.The challenges and opportunities on the further development of electrocatalysts for fuel cells are included to provide reference for the practical application.
基金supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MSIT) (RS-2023-00210114)supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2021R1C1C1004264 and NRF2021R1A4A1032114)+1 种基金supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MSIT) (NRF-2022R1A4A1019296)supported by the National R&D Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science and ICT (2021M3D1A2051636)。
文摘Mixed metal oxide(MMO) represents a critical class of materials that can allow for obtaining a dynamic interface between its components:reduced metal and its metal oxide counterpart during an electrocatalytic reaction.Here,a synthetic method utilizing a MOF-derived micro/mesoporous carbon as a template to prepare sub-2 nm MMO catalysts for CO_(2) electro reduction is reported.Starting from the zeolite imidazolate framework(ZIF-8),the pyrolyzed derivatives were used to synthesize sub-2 nm Pd-Ni MMO with different compositions.The Ni-rich(Pd_(20)-Ni_(80)/ZC) catalyst exhibits unexpectedly superior performance for CO production with an improved Faradaic efficiency(FE) of 95.3% at the current density of 200 mA cm^(-2) at-0.56 V vs.reversible hydrogen electrode(RHE) compared to other Pd-Ni compositions.X-ray photoelectron spectroscopy(XPS) analysis confirms the presence of Ni^(2+) and Pd^(2+) in all compositions,demonstrating the presence of MMO.Density functional theory(DFT) calculation reveals that the lower CO binding energy on the surface of the Pd_(20)-Ni_(80) cluster eases CO desorption,thus increasing its production.This work provides a general synthetic strategy for MMO electrocatalysts and can pave a new way for screening multimetallic catalysts with a dynamic electrochemical interface.
