摘要
This study explores a novel strategy to enhance the hydrogen evolution reaction(HER)activity of carbon-supported rock salt-type NiCo_(2)(O,F)_(3) nanorods through lattice modifications induced by fluorine and excess amorphous carbon.X-ray absorption near-edge structure(XANES)analysis confirmed that Co and Ni predominantly exist in the+2 oxidation state,whereas extended X-ray absorption fine structure(EXAFS)analysis revealed shortened Co-O and Co-Co bond lengths,indicating lattice distortions.Rietveld refinement and electron microscopy confirmed the formation of a homogeneous solid solution(NixCo_(2-x)(O,F)_(3))rather than a simple CoO/NiO composite.The optimized material(AH-2)exhibited the lowest overpotential(145 mV at 10 mA cm^(-1))and the smallest Tafel slope(98 mV dec^(-1)),attributed to its balanced phase composition,enhanced electronic conductivity,and synergistic effects of carbon and fluorine incorporation.Electrochemical impedance spectroscopy(EIS)confirmed improved charge transfer efficiency,correlating with enhanced catalytic activity.These findings provide critical insights into the tunability of transition metal oxide catalysts via controlled lattice modifications,offering a promising avenue for developing cost-effective and efficient electrocatalysts for sustainable hydrogen production.
基金
supported by the Russian Science Foundation(project No.24-43-00215,http://rscf.ru/project/24-43-00215/).
