Ultra-high-rate CO2 reduction reactions to multicarbon products with a current density of 1.7 A/cm2 in neutral electrolytes

CO2 electrolysis to value-added products is a promising technology to close the carbon cycle and sequester anthropogenic CO2 into chemical feedstocks; an increase of the current density for multicarbon products is one of the requirements for practical implementation. We have successfully increased the partial current density for gaseous CO2 reduction reactions to multicarbon products (C2+) over Cu nanoparticles on gas diffusion electrodes in neutral electrolytes to a record value of 1.7 A/cm2. The faradaic efficiency for multicarbon products increased with the current density and reached 76% at a total current density of 1.6 A/cm2. The turnover frequency for the production of C2+ per Cu atoms exceeded 2.8 s-1. The optimal porosity and thickness of the catalyst layer are confirmed as factors that elicit the high-turnover frequency of Cu atoms, resulting in the record partial current density for C2+.