Steering post-C–C coupling selectivity enables high efficiency electroreduction of carbon dioxide to multi-carbon alcohols

Engineering copper-based catalysts that favour high-value alcohols is desired in view of the energy density, ready transport and established use of these liquid fuels. In the design of catalysts, much progress has been made to target the C–C coupling step; whereas comparatively little effort has been expended to target post-C–C coupling reaction intermediates. Here we report a class of core–shell vacancy engineering catalysts that utilize sulfur atoms in the nanoparticle core and copper vacancies in the shell to achieve efficient electrochemical CO2 reduction to propanol and ethanol. These catalysts shift selectivity away from the competing ethylene reaction and towards liquid alcohols. We increase the alcohol-to-ethylene ratio more than sixfold compared with bare-copper nanoparticles, highlighting an alternative approach to electroproduce alcohols instead of alkenes. We achieve a C2+ alcohol production rate of 126 ± 5 mA cm−2 with a selectivity of 32 ± 1% Faradaic efficiency. The conversion of carbon dioxide into multi-carbon alcohols would enable the synthesis of sustainable liquid fuels with high energy densities. Now, vacancy-engineered core–shell copper-based catalysts are able to shift the selectivity of electrochemical CO2 reduction into alcohols instead of alkenes, as obtained with bare-copper catalysts.