Atomic transition metal–nitrogen–carbon electrocatalysts exhibit outstanding activity in various electrocatalytic reactions.The challenge lies in predicting the structure of the active center,which may undergo chang...Atomic transition metal–nitrogen–carbon electrocatalysts exhibit outstanding activity in various electrocatalytic reactions.The challenge lies in predicting the structure of the active center,which may undergo changes under applied potential and interact with reactants or intermediates.Advanced characterization techniques,particularly in-situ X-ray absorption spectroscopy(XAS),provide crucial insights into the structural evolution of the metal active center during the reaction.In this study,nitrate reduction to ammonia(NO_(3)RR)was selected as a model reaction,and we introduced in-situ XAS to reveal the structural evolution during the catalytic process.A novel single atom catalyst of iron loaded on three-dimensional nitrogen–carbon nanonetwork(designated as Fe SAC/NC)was successfully synthesized.We unraveled the structural transformations occurring as pyrrole-N_(4)-Fe transitions to pyrrole-N_(3)-Fe throughout the NO_(3)RR process.Notably,the Fe SAC/NC catalyst exhibited excellent catalytic activity,achieving a Faradaic efficiency of 98.2% and an ammonia generation rate of 22,515μg·h^(−1)·mgcat−1 at−0.8 V versus reversible hydrogen electrode.Theoretical calculations combined with in-situ spectroscopic characterization showed that pyrrole-N_(3)-Fe reduced the energy barrier from *NO to*NHO and improved the selectivity of ammonia.This provides a robust reference for the design of efficient nitrate-to-ammonia synthesis catalysts.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22002013 and 52272193)the Fundamental Research Funds for the Central Universities(Nos.DUT22LAB602 and DUT20RC(3)021)+1 种基金Liaoning Revitalization Talents Program(No.XLYC2008032)China Postdoctoral Science Foundation(No.2023M740496)。
文摘Atomic transition metal–nitrogen–carbon electrocatalysts exhibit outstanding activity in various electrocatalytic reactions.The challenge lies in predicting the structure of the active center,which may undergo changes under applied potential and interact with reactants or intermediates.Advanced characterization techniques,particularly in-situ X-ray absorption spectroscopy(XAS),provide crucial insights into the structural evolution of the metal active center during the reaction.In this study,nitrate reduction to ammonia(NO_(3)RR)was selected as a model reaction,and we introduced in-situ XAS to reveal the structural evolution during the catalytic process.A novel single atom catalyst of iron loaded on three-dimensional nitrogen–carbon nanonetwork(designated as Fe SAC/NC)was successfully synthesized.We unraveled the structural transformations occurring as pyrrole-N_(4)-Fe transitions to pyrrole-N_(3)-Fe throughout the NO_(3)RR process.Notably,the Fe SAC/NC catalyst exhibited excellent catalytic activity,achieving a Faradaic efficiency of 98.2% and an ammonia generation rate of 22,515μg·h^(−1)·mgcat−1 at−0.8 V versus reversible hydrogen electrode.Theoretical calculations combined with in-situ spectroscopic characterization showed that pyrrole-N_(3)-Fe reduced the energy barrier from *NO to*NHO and improved the selectivity of ammonia.This provides a robust reference for the design of efficient nitrate-to-ammonia synthesis catalysts.
