Abstract
Methane oxidation to value-added chemicals under mild conditions remained a research challenge and has attracted continuous attention, owing to fundamental interest and practical significance. Herein we report fundamental study of electrochemical methane oxidation reaction (CH4OR) on iron-nickel hydroxide (Fe-Ni-OH) nanosheets with controlled composition. The Fe-Ni-OH catalysts exhibit interesting CH4OR activity towards ethanol production in the Ni(II)→Ni(III) transition potential range and show a strong composition effect on the activity property, with a 9.09 mmol/gcataiysfh ethanol formation rate, 87 % faradaic efficiency, and 0.26 s~(-1) turnover frequency achieved using Fe3Ni7(OH)_x at 1.46 V vs. RHE. Density functional theory simulations and in situ infrared characterizations suggest Ni~IIIOOH as the active site and plausible CH4OR pathways, with the reaction barriers being altered with Fe-Ni-OH composition that agrees with the experimental observations. We believe this study provides new insights into CH4OR electrocatalysis mechanisms and offers theoretical guidance in discovering advanced catalyst materials for effective methane conversion.
NSTL