Developing cost-effective,robust and stable non-precious metal catalysts for oxygen reduction reaction(ORR) is of paramount importance for electrochemical energy conversion devices such as fuel cells and metal-air bat...Developing cost-effective,robust and stable non-precious metal catalysts for oxygen reduction reaction(ORR) is of paramount importance for electrochemical energy conversion devices such as fuel cells and metal-air batteries.Although Fe-N-C single atom catalysts(SACs) have been hailed as the most promising candidate due to the optimal binding strength of ORR intermediates on the Fe-N_(4) sites,they suffer from serious mass transport limitations as microporous templates/substrates,i.e.,zeolitic imidazolate frameworks(ZIFs),are usually employed to host the active sites.Motivated by this challenge,we herein develop a hydrogen-bonded organic framework(HOF)-assisted pyrolysis strategy to construct hierarchical micro/mesoporous carbon nanoplates for the deposition of atomically dispersed Fe-N_(4) sites.Such a design is accomplished by employing HOF nanoplates assembled from 2-aminoterephthalic acid(NH_(2)-BDC) and p-phenylenediamine(PDA) as both soft templates and C,N precursors.Benefitting from the structural merits inherited from HOF templates,the optimized catalyst(denoted as Fe-N-C SAC-950) displays outstanding ORR activity with a high half-wave potential of 0.895 V(vs.reversible hydrogen electrode(RHE)) and a small overpotential of 356 mV at 10 mA cm^(-2) for the oxygen evolution reaction(OER).More excitingly,its application potential is further verified by delivering superb rechargeability and cycling stability with a nearly unfading charge-discharge gap of 0.72 V after 160 h.Molecular dynamics(MD) simulations reveal that micro/mesoporous structure is conducive to the rapid mass transfer of O_(2),thus enhancing the ORR performance.In situ Raman results further indicate that the conversion of O_(2) to~*O_(2)-the rate-determining step(RDS) for Fe-N-C SAC-950.This work will provide a versatile strategy to construct single atom catalysts with desirable catalytic properties.展开更多
The development of cost-effective,robust,and durable electrocatalysts to replace the expensive Pt-based catalysts towards oxygen reduction reaction(ORR)is the trending frontier research topic in renewable energy and e...The development of cost-effective,robust,and durable electrocatalysts to replace the expensive Pt-based catalysts towards oxygen reduction reaction(ORR)is the trending frontier research topic in renewable energy and electrocatalysis.Particular attention has been paid to metal-nitrogen-carbon(M-N-C)single atom catalysts(SACs)due to their maximized atom utilization efficiency,biomimetic active site,and distinct electronic structure.More importantly,their catalytic properties can be further tailored by rationally regulating the microenvironment of active sites(i.e.,M-N coordination number,heteroatom doping and substitution.Herein,we present a comprehensive summary of the recent advancement in the microenvironment regulation of MN-C SACs towards improved ORR performance.The coordination environment manipulation regarding central metal and coordinated atoms is first discussed,focusing on the structure-function relationship.Apart from the near-range coordination,longrange substrate modulation including heteroatom doping,defect engineering is discussed as well.Besides,the synergy mechanism of nanoparticles and single atom sites to tune the electron cloud density at the active sites is summarized.Finally,we provide the challenges and outlook of the development of M-N-C SACs.展开更多
Although fuel cells possess advantages of high energy conversion efficiency and zero-carbon emission,their large-scale commercialization is restricted by expensive and scarce platinum(Pt)catalysts.Metal-nitrogen-carbo...Although fuel cells possess advantages of high energy conversion efficiency and zero-carbon emission,their large-scale commercialization is restricted by expensive and scarce platinum(Pt)catalysts.Metal-nitrogen-carbon(M-Nx/C)catalysts are hailed as the most promising candidates to replace Pt due to their considerable oxygen reduction reaction(ORR)activity and low cost.Despite tremendous progress in terms of active site identification and activity improvement being achieved in the past few decades,the M-Nx/C catalysts still suffer from insufficient durability,which drastically limits their practical application.In this regard,understanding degradation mechanisms and customizing stabilization strategies are of significant importance yet challengeable.In this review,we summarize the recent advances in the stability improvement of M-Nx/C catalysts.The stability test protocols of the M-Nx/C are firstly introduced.Subsequently,with the combination of advanced ex situ and in situ characterization techniques and density functional theory calculation,we present a comprehensive overview of the main degradation mechanisms during ORR process.Aiming at these deactivation issues,a variety of novel improvement strategies are developed to enhance the stability of M-Nx/C.Finally,the current challenges and prospects to design highly stable M-Nx/C catalysts are also proposed.展开更多
基金financially supported by the National Key R&D Program of China(2022YFB4004100)the National Natural Science Foundation of China(22272161)+6 种基金the Jilin Province Science and Technology Development Program(20230101367JC)financially supported by the National Natural Science Foundation of China(22073094)the Science and Technology Development Program of Jilin Province(20210402059GH)the Science and Technology Plan Projects of Yunnan Province(202101BC070001–007)the Major Science and Technology Projects for Independent Innovation of China FAW Group Co.,Ltd(20220301018GX)the essential support of the Network and Computing Center,CIAC,CASthe Computing Center of Jilin Province。
文摘Developing cost-effective,robust and stable non-precious metal catalysts for oxygen reduction reaction(ORR) is of paramount importance for electrochemical energy conversion devices such as fuel cells and metal-air batteries.Although Fe-N-C single atom catalysts(SACs) have been hailed as the most promising candidate due to the optimal binding strength of ORR intermediates on the Fe-N_(4) sites,they suffer from serious mass transport limitations as microporous templates/substrates,i.e.,zeolitic imidazolate frameworks(ZIFs),are usually employed to host the active sites.Motivated by this challenge,we herein develop a hydrogen-bonded organic framework(HOF)-assisted pyrolysis strategy to construct hierarchical micro/mesoporous carbon nanoplates for the deposition of atomically dispersed Fe-N_(4) sites.Such a design is accomplished by employing HOF nanoplates assembled from 2-aminoterephthalic acid(NH_(2)-BDC) and p-phenylenediamine(PDA) as both soft templates and C,N precursors.Benefitting from the structural merits inherited from HOF templates,the optimized catalyst(denoted as Fe-N-C SAC-950) displays outstanding ORR activity with a high half-wave potential of 0.895 V(vs.reversible hydrogen electrode(RHE)) and a small overpotential of 356 mV at 10 mA cm^(-2) for the oxygen evolution reaction(OER).More excitingly,its application potential is further verified by delivering superb rechargeability and cycling stability with a nearly unfading charge-discharge gap of 0.72 V after 160 h.Molecular dynamics(MD) simulations reveal that micro/mesoporous structure is conducive to the rapid mass transfer of O_(2),thus enhancing the ORR performance.In situ Raman results further indicate that the conversion of O_(2) to~*O_(2)-the rate-determining step(RDS) for Fe-N-C SAC-950.This work will provide a versatile strategy to construct single atom catalysts with desirable catalytic properties.
基金supported by the National Natural Science Foundation of China(No.22272161).
文摘The development of cost-effective,robust,and durable electrocatalysts to replace the expensive Pt-based catalysts towards oxygen reduction reaction(ORR)is the trending frontier research topic in renewable energy and electrocatalysis.Particular attention has been paid to metal-nitrogen-carbon(M-N-C)single atom catalysts(SACs)due to their maximized atom utilization efficiency,biomimetic active site,and distinct electronic structure.More importantly,their catalytic properties can be further tailored by rationally regulating the microenvironment of active sites(i.e.,M-N coordination number,heteroatom doping and substitution.Herein,we present a comprehensive summary of the recent advancement in the microenvironment regulation of MN-C SACs towards improved ORR performance.The coordination environment manipulation regarding central metal and coordinated atoms is first discussed,focusing on the structure-function relationship.Apart from the near-range coordination,longrange substrate modulation including heteroatom doping,defect engineering is discussed as well.Besides,the synergy mechanism of nanoparticles and single atom sites to tune the electron cloud density at the active sites is summarized.Finally,we provide the challenges and outlook of the development of M-N-C SACs.
基金supported by the National Key R&D Program of China(grant no.2022YFB4004100)National Natural Science Foundation of China(grant nos.22272161 and 22179126)Jilin Province Science and Technology Development Program(grant no.20230101367JC).
文摘Although fuel cells possess advantages of high energy conversion efficiency and zero-carbon emission,their large-scale commercialization is restricted by expensive and scarce platinum(Pt)catalysts.Metal-nitrogen-carbon(M-Nx/C)catalysts are hailed as the most promising candidates to replace Pt due to their considerable oxygen reduction reaction(ORR)activity and low cost.Despite tremendous progress in terms of active site identification and activity improvement being achieved in the past few decades,the M-Nx/C catalysts still suffer from insufficient durability,which drastically limits their practical application.In this regard,understanding degradation mechanisms and customizing stabilization strategies are of significant importance yet challengeable.In this review,we summarize the recent advances in the stability improvement of M-Nx/C catalysts.The stability test protocols of the M-Nx/C are firstly introduced.Subsequently,with the combination of advanced ex situ and in situ characterization techniques and density functional theory calculation,we present a comprehensive overview of the main degradation mechanisms during ORR process.Aiming at these deactivation issues,a variety of novel improvement strategies are developed to enhance the stability of M-Nx/C.Finally,the current challenges and prospects to design highly stable M-Nx/C catalysts are also proposed.