The development of efficient electrocatalysts for the nitrogen oxidation reaction(NOR)under mild conditions is crucial for sustainable nitrate synthesis.Mo-dopedδ-MnO_(2)electrocatalysts with varying Mo concentration...The development of efficient electrocatalysts for the nitrogen oxidation reaction(NOR)under mild conditions is crucial for sustainable nitrate synthesis.Mo-dopedδ-MnO_(2)electrocatalysts with varying Mo concentrations were successfully prepared for the NOR.Structural and electrochemical analyses revealed that Mo doping simultaneously enhanced the conductivity and electrochemically active surface area(ECSA)while promoting N_(2)adsorption and activation through electronic structure modulation.The optimized 2.5%Mo-dopedδ-MnO_(2)(denoted as MM2.5)exhibited superior NOR performance in 0.1 M KOH,delivering a NO_(3)^(−)production rate of 116.75μg h^(−1)mg_(cat)^(−1)with a faradaic efficiency(FE)of 7.04%and excellent long-term stability.In addition,a Zn–N_(2)device was formed with MM2.5 as the anode and a Zn plate as the cathode,and the NO_(3)^(−)yield obtained in this device was even higher than 144.5μg h^(−1)mg_(cat)^(−1).However,structural characterization revealed that excessive Mo doping disrupted theδ-MnO_(2)crystal structure,reducing specific surface area and active site density.Density functional theory(DFT)calculations demonstrated that Mo doping lowered the Gibbs free energy of the rate-determining step(*N_(2)→*NNOH)from 2.41 eV to 1.94 eV by facilitating electron transfer,thereby optimizing the reaction pathway.This study provides a new strategy for the design of transition metal oxide-based electrocatalysts,as well as the application in artificial nitrogen fixation.展开更多
基金support from the Natural Science Foundation of Shandong Province(ZR2021MB075 and ZR2025MS209)the National Natural Science Foundation of China(51602297)Fundamental Research Funds for the Central Universities,Ocean University of China(202461021 and 202364004).
文摘The development of efficient electrocatalysts for the nitrogen oxidation reaction(NOR)under mild conditions is crucial for sustainable nitrate synthesis.Mo-dopedδ-MnO_(2)electrocatalysts with varying Mo concentrations were successfully prepared for the NOR.Structural and electrochemical analyses revealed that Mo doping simultaneously enhanced the conductivity and electrochemically active surface area(ECSA)while promoting N_(2)adsorption and activation through electronic structure modulation.The optimized 2.5%Mo-dopedδ-MnO_(2)(denoted as MM2.5)exhibited superior NOR performance in 0.1 M KOH,delivering a NO_(3)^(−)production rate of 116.75μg h^(−1)mg_(cat)^(−1)with a faradaic efficiency(FE)of 7.04%and excellent long-term stability.In addition,a Zn–N_(2)device was formed with MM2.5 as the anode and a Zn plate as the cathode,and the NO_(3)^(−)yield obtained in this device was even higher than 144.5μg h^(−1)mg_(cat)^(−1).However,structural characterization revealed that excessive Mo doping disrupted theδ-MnO_(2)crystal structure,reducing specific surface area and active site density.Density functional theory(DFT)calculations demonstrated that Mo doping lowered the Gibbs free energy of the rate-determining step(*N_(2)→*NNOH)from 2.41 eV to 1.94 eV by facilitating electron transfer,thereby optimizing the reaction pathway.This study provides a new strategy for the design of transition metal oxide-based electrocatalysts,as well as the application in artificial nitrogen fixation.
