High-Rate CO2 Electroreduction to C2+ Products over a Copper-Copper Iodide Catalyst.

Electrochemical CO 2 reduction reaction (CO 2 RR) to multicarbon hydrocarbon and oxygenate (C 2+ ) products with high energy density and wide availability is of great importance, as it provides a promising way to achieve the renewable energy storage and close the carbon cycle. Herein we design a Cu-CuI composite catalyst with abundant Cu/Cu + interfaces by physically mixing Cu nanoparticles and CuI powders. The composite catalyst achieves a remarkable C 2+ partial current density of 591 mA cm -2 at -1.0 V vs. reversible hydrogen electrode in a flow cell, substantially higher than Cu (329 mA cm -2 ) and CuI (96 mA cm -2 ) counterparts. Induced by alkaline electrolyte and applied potential, the Cu-CuI composite catalyst undergoes significant reconstruction under CO 2 RR conditions. Structural characterizations and theoretical calculations indicate that the high-rate C 2+ production over Cu-CuI is ascribed to the presence of residual Cu + and adsorbed iodine species which improve CO adsorption and facilitate C-C coupling.