Electrocatalytic methane oxidation to ethanol on iron-nickel hydroxide nanosheets

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 (CH 4 OR) on iron-nickel hydroxide (Fe-Ni-OH) nanosheets with controlled composition. The Fe-Ni-OH catalysts exhibit interesting CH 4 OR 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/g catalyst ·h ethanol formation rate, 87 % faradaic efficiency, and 0.26 s −1 turnover frequency achieved using Fe 3 Ni 7 (OH) x at 1.46 V vs. RHE. Density functional theory simulations and in situ infrared characterizations suggest Ni III OOH as the active site and plausible CH 4 OR 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 CH 4 OR electrocatalysis mechanisms and offers theoretical guidance in discovering advanced catalyst materials for effective methane conversion. • Fe-Ni-OH nanosheets exhibit interesting catalytic properties and strong composition effect in electrochemical methane oxidation. • 9.09 mmol/g catalyst ·h ethanol formation rate, 87 % faradaic efficiency (FE), and 0.26 s −1 turnover frequency are achieved with Fe 3 Ni 7 (OH) x at 1.46 V vs. RHE. • Ni III OOH is identified as the active site in CH 4 OR.