Inspired by molecular catalysts,researchers developed atomically precise nitrogen-coordinated single or dual metal sites imbedded in graphitized carbon(M-N-C)to fully utilize metallic sites for 02activation.These cata...Inspired by molecular catalysts,researchers developed atomically precise nitrogen-coordinated single or dual metal sites imbedded in graphitized carbon(M-N-C)to fully utilize metallic sites for 02activation.These catalysts performed remarkably well in the electrocatalytic oxygen reduction reaction(ORR)due to their distinct coordination and electrical structures,Nonetheless,their maximum efficacy in practical applications has yet to be achieved.This agenda identifies tailoring the coordination environment,spin states,intersite distance,and metal-metal interaction as innovative approaches to regulate the ORR performance of these catalysts.However,it is necessary to undertake a precise assessment of these methodologies and the knowledge obtained to be implemented in the design of future M-N-C catalysts for ORR.Therefore,this review aims to analyze recent progress in M-N-C ORR catalysts,emphasizing their innovative engineering with aspects such as alteration in intersite distance,metal-metal interaction,coordination environment,and spin states.Additionally,we critically discuss how to logically monitor the atomic structure,local coordination,spin,and electronic states of M-N-C catalysts to modulate their ORR activity.We have also highlighted the challenges associated with M-N-C catalysts and proposed suggestions for their future design and fabrication.展开更多
To enhance the efficiency of green energy harvesting and pollutant degradation,significant efforts are focused on identifying highly effective catalysts.Metal-nitrogen-carbon single-atom catalysts(M-N-C SACs)have emer...To enhance the efficiency of green energy harvesting and pollutant degradation,significant efforts are focused on identifying highly effective catalysts.Metal-nitrogen-carbon single-atom catalysts(M-N-C SACs)have emerged as pivotal in catalysis due to their unique geometric structures,electronic states,and catalytic capabilities.Notably,the incorporation of magnetic elements at the active centers of these single-atom catalysts has garnered attention for their role in efficient electrochemical conversions.The orientation of spin states critically influences the adsorption and formation of reactants and intermediates,making the precise control of spin alignment and magnetic moments essential for reducing energy barriers and overcoming spin-related limitations,thereby enhancing catalytic activity.Thus,understanding the catalytic role of spin and modulating spin density at M-N-C single-atom centers holds profound fundamental and technological significance.In this review,we elucidate the fundamental mechanisms governing spin states and its influence in electrocatalysis.We then discuss various strategies for adjusting the spin states of active centers in the M-N-C SACs and the associated characterization techniques.Finally,we outline challenges and future perspectives of spin regulation for high-performance catalysts.This review provides deep insights into the micro-mechanisms of catalytic phenomena and offers a roadmap for designing spin-regulated catalysts for advanced energy applications.展开更多
Atomically dispersed transition metal(M)and nitrogen(N)co-doped carbon(M-N-C)electrocatalysts hold excellent application potentials for several critical reactions required in electrochemical conversion processes and e...Atomically dispersed transition metal(M)and nitrogen(N)co-doped carbon(M-N-C)electrocatalysts hold excellent application potentials for several critical reactions required in electrochemical conversion processes and energy storage devices,including oxygen reduction reaction,oxygen evolution reaction,hydrogen evolution reaction,carbon dioxide reduction reaction and nitrogen reduction reaction.Despite significant progress achieved in the past few decades,their commercialization is hindered by their fast degradation.This perspective article outlines the historical development of M-N-C electrocatalysts,the current understanding of their active catalytic sites,and crucial degradation mechanisms.We highlight that many methods used to tailor M-N-C electrocatalysts likely cause contradictory effects on activity and stability.More emphasis is needed to address their degradation issues under industryrelevant working conditions.展开更多
Proton exchange membrane fuel cells(PEMFCs)as promising alternatives to traditional internal combustion engines have attracted massive concerns to promote their wide application in society.However,the biggest challeng...Proton exchange membrane fuel cells(PEMFCs)as promising alternatives to traditional internal combustion engines have attracted massive concerns to promote their wide application in society.However,the biggest challenge to the commercialization of PEMFCs remains the high cost due to the adoption of the platinum group metal(PGM)catalysts in the cathode.展开更多
The development of highly efficient non-precious metal-nitrogen-carbon(M-N-C)electrocatalysts is a key scientific issue for improving the performance of metal-air batteries and fuel cells.Due to the symmetric charge d...The development of highly efficient non-precious metal-nitrogen-carbon(M-N-C)electrocatalysts is a key scientific issue for improving the performance of metal-air batteries and fuel cells.Due to the symmetric charge distribution of the traditional M-N_(4)active site,the adsorption energy of the key oxygen intermediates in the process of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is difficult to reach the optimal value,which seriously limits the catalytic efficiency.The core of solving this problem lies in the accurate modulation of the coordination environment of the M-N_(4)site,which can realize the breakthrough improvement of the catalytic performance by synergistically optimizing the geometric configuration and electronic structure.In this paper,we systematically analyze the ORR/OER reaction mechanism and then comprehensively review the four main strategies to optimize the coordination environment of M-N-C:metal site regulation,coordination number engineering,non-metal atom doping,and carbon support regulation.Through an in-depth analysis of the structure-activity relationship between the coordination configuration and catalytic performance,the core challenges faced by current research are pointed out,and future research directions are envisioned.This work aims to provide theoretical references for the directional construction of highly efficient M-N-C catalysts with optimized coordination environments.展开更多
基金supported by the Research Fund for International Scientists(RFIS-Grant numbers:52150410410)National Natural Science Foundation of Chinathe Deanship of Scientific Research and Graduate Studies at King Khalid University for funding this research work through Large Research Project under the grant number RGP2/121/1445.
文摘Inspired by molecular catalysts,researchers developed atomically precise nitrogen-coordinated single or dual metal sites imbedded in graphitized carbon(M-N-C)to fully utilize metallic sites for 02activation.These catalysts performed remarkably well in the electrocatalytic oxygen reduction reaction(ORR)due to their distinct coordination and electrical structures,Nonetheless,their maximum efficacy in practical applications has yet to be achieved.This agenda identifies tailoring the coordination environment,spin states,intersite distance,and metal-metal interaction as innovative approaches to regulate the ORR performance of these catalysts.However,it is necessary to undertake a precise assessment of these methodologies and the knowledge obtained to be implemented in the design of future M-N-C catalysts for ORR.Therefore,this review aims to analyze recent progress in M-N-C ORR catalysts,emphasizing their innovative engineering with aspects such as alteration in intersite distance,metal-metal interaction,coordination environment,and spin states.Additionally,we critically discuss how to logically monitor the atomic structure,local coordination,spin,and electronic states of M-N-C catalysts to modulate their ORR activity.We have also highlighted the challenges associated with M-N-C catalysts and proposed suggestions for their future design and fabrication.
文摘To enhance the efficiency of green energy harvesting and pollutant degradation,significant efforts are focused on identifying highly effective catalysts.Metal-nitrogen-carbon single-atom catalysts(M-N-C SACs)have emerged as pivotal in catalysis due to their unique geometric structures,electronic states,and catalytic capabilities.Notably,the incorporation of magnetic elements at the active centers of these single-atom catalysts has garnered attention for their role in efficient electrochemical conversions.The orientation of spin states critically influences the adsorption and formation of reactants and intermediates,making the precise control of spin alignment and magnetic moments essential for reducing energy barriers and overcoming spin-related limitations,thereby enhancing catalytic activity.Thus,understanding the catalytic role of spin and modulating spin density at M-N-C single-atom centers holds profound fundamental and technological significance.In this review,we elucidate the fundamental mechanisms governing spin states and its influence in electrocatalysis.We then discuss various strategies for adjusting the spin states of active centers in the M-N-C SACs and the associated characterization techniques.Finally,we outline challenges and future perspectives of spin regulation for high-performance catalysts.This review provides deep insights into the micro-mechanisms of catalytic phenomena and offers a roadmap for designing spin-regulated catalysts for advanced energy applications.
基金supported by the Australian Research Council under the Future Fellowships scheme(FT160100107)。
文摘Atomically dispersed transition metal(M)and nitrogen(N)co-doped carbon(M-N-C)electrocatalysts hold excellent application potentials for several critical reactions required in electrochemical conversion processes and energy storage devices,including oxygen reduction reaction,oxygen evolution reaction,hydrogen evolution reaction,carbon dioxide reduction reaction and nitrogen reduction reaction.Despite significant progress achieved in the past few decades,their commercialization is hindered by their fast degradation.This perspective article outlines the historical development of M-N-C electrocatalysts,the current understanding of their active catalytic sites,and crucial degradation mechanisms.We highlight that many methods used to tailor M-N-C electrocatalysts likely cause contradictory effects on activity and stability.More emphasis is needed to address their degradation issues under industryrelevant working conditions.
文摘Proton exchange membrane fuel cells(PEMFCs)as promising alternatives to traditional internal combustion engines have attracted massive concerns to promote their wide application in society.However,the biggest challenge to the commercialization of PEMFCs remains the high cost due to the adoption of the platinum group metal(PGM)catalysts in the cathode.
基金supported by the Natural Science Foundation of Hebei Province(no.E2024501010)the National Natural Science Foundation of China(no.52374301)+1 种基金the Shijiazhuang Basic Research Project(no.241790667A)the Performance Subsidy Fund for Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province(no.22567627H)。
文摘The development of highly efficient non-precious metal-nitrogen-carbon(M-N-C)electrocatalysts is a key scientific issue for improving the performance of metal-air batteries and fuel cells.Due to the symmetric charge distribution of the traditional M-N_(4)active site,the adsorption energy of the key oxygen intermediates in the process of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is difficult to reach the optimal value,which seriously limits the catalytic efficiency.The core of solving this problem lies in the accurate modulation of the coordination environment of the M-N_(4)site,which can realize the breakthrough improvement of the catalytic performance by synergistically optimizing the geometric configuration and electronic structure.In this paper,we systematically analyze the ORR/OER reaction mechanism and then comprehensively review the four main strategies to optimize the coordination environment of M-N-C:metal site regulation,coordination number engineering,non-metal atom doping,and carbon support regulation.Through an in-depth analysis of the structure-activity relationship between the coordination configuration and catalytic performance,the core challenges faced by current research are pointed out,and future research directions are envisioned.This work aims to provide theoretical references for the directional construction of highly efficient M-N-C catalysts with optimized coordination environments.
