Solar Cell-Powered Electrochemical Methane-to-Methanol Conversion with CuO/CeO₂ Catalysts

Abstract

Electrochemical CH4 oxidation is attractive as a strategy capable of conversion with high selectivity, but improving productivity remains a challenge. We demonstrate that CuO/CeO2 can serve as a catalyst for the room-temperature conversion of CH4 to CH3OH in the presence of CO32–. At an optimized ratio of CuO/CeO2 (Cu:Ce = 6:4), we achieve the highest production rate of 752.9 μmol/gcat/h (6 h reaction) at ambient pressure; among the oxygenates, a CH3OH selectivity of 79% is obtained. In an experiment using isotopes, we confirm that CH4 is activated by active oxygen on the catalyst surface provided from CO32– to form CH3OH. Furthermore, we demonstrate a solar cell-powered electrochemical CH4 conversion. In the 12 h reaction, a CH3OH production of 7165.0 μmol/gcat at ambient pressure and 21986.6 μmol/gcat at 10 bar is obtained.