Customized CO2 electroreduction to methane or ethylene by manipulating *H and *CO adsorption on Cu/CeOx catalysts

Abstract

The coverage of *CO and *H intermediates on the surface of a catalyst plays a pivotal role in determining the selectivity towards C1 or C2 products in the electrochemical CO2 reduction reaction (CO2RR). In this study, we engineered two types of interfaces involving copper and rare earth metal oxides, specifically Cu/CeOx and Cu/CuCeOx solid solution, which exhibit enhanced binding affinities for *H and *CO adsorbates in the CO2RR, respectively. As a result, the Cu/CuCeOx catalyst delivered an ethylene Faradaic efficiency of 40.2% at a partial current density of -245.7 mA cm-2, whereas the Cu/CeOx catalyst presented a methane Faradaic efficiency of 38.6% at a partial current density of -198.3 mA cm-2. Results of theoretical and experimental analyses have demonstrated that the Cu-Ce-Ox solid solution markedly enhances *CO adsorption by stabilizing Cu+ species, thereby favoring its dimerization to ethylene rather than converting to methane through hydrogenation. This investigation elucidates a strategy for directing the selective electroproduction of C1 or C2 compounds from CO2RR by effectively manipulating *H and *CO adsorption on Cu/CeOx catalysts.