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/CeO_x and Cu/CuCeO_x solid solution, which exhibit enhanced binding affinities for *H and *CO adsorbates in the CO₂RR, respectively. As a result, the Cu/CuCeO_x catalyst delivered an ethylene faradaic efficiency of 40.2% at a partial current density of −245.7 mA cm⁻², whereas the Cu/CeO_x 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–O_x 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 the CO₂RR by effectively manipulating *H and *CO adsorption on Cu/CeO_x catalysts.