Unprecedented Direct Methanol Coupling for Selective Conversion of CO2 to Ethane at Room Temperature and Ambient Pressure

Abstract

Effective electrocatalysts with high activity and selectivity for carbon dioxide (CO2) reduction to multi-carbon (C2+) products are still lacking. CO dimerization to C2+ products such as ethylene and ethanol can be achieved on Cu-based catalysts, but direct coupling to ethane (C2H6) has not been realized. Here, we show high selectivity of CO2 to C2H6 at room temperature and ambient pressure. Specifically, we report both experimental and theoretical findings for the Ti2N electrocatalyst, that exhibits the highest reported Faradaic efficiency (FE) for C2H6 (~ 46.8%) at a current density of 25 mA cm− 2 and potential of -1.44 V versus the reversible hydrogen electrode (RHE) with ethane energy efficiency of ~ 20%. We achieve this outstanding performance via an alternative reaction pathway, where the *CH3OH adsorbed species are stabilized on the catalyst surface, which facilitates the production of C2H6 through the *CH3OH coupling mechanism as corroborated by density functional theory (DFT). We demonstrate that the high selectivity is accompanied by excellent catalytic, structural, and electronic stability as evidenced by XAS, TEM, FTIR and SEM measurements. These groundbreaking chemistry advancements and catalysts unveil uncharted avenues for converting CO2 into liquid fuels and chemicals.