Enhanced multi-carbon alcohol electroproduction from CO via modulated hydrogen adsorption

Abstract

Multi-carbon alcohols such as ethanol are valued as fuels in view of their high energy density and ready transport. Unfortunately, the selectivity toward alcohols in CO₂/CO electroreduction is diminished by ethylene production, especially when operating at high current densities (>100 mA cm⁻²). Here we report a metal doping approach to tune the adsorption of hydrogen at the copper surface and thereby promote alcohol production. Using density functional theory calculations, we screen a suite of transition metal dopants and find that incorporating Pd in Cu moderates hydrogen adsorption and assists the hydrogenation of C₂ intermediates, providing a means to favour alcohol production and suppress ethylene. We synthesize a Pd-doped Cu catalyst that achieves a Faradaic efficiency of 40% toward alcohols and a partial current density of 277 mA cm⁻² from CO electroreduction. The activity exceeds that of prior reports by a factor of 2.