Tuning product distributions of CO2 electroreduction over copper foil through cathodic corrosion

Electrocatalytic CO2 reduction is an effective way to close the global carbon cycle. Copper is a promising metal for CO2 conversion to multiple products but suffers from low selectivity. Here commercial copper foil is exploited as an efficient catalyst for CO2 reduction with tunable product distributions through electrochemical processing. Ultrafine Cu nanoparticles were generated with dominant (1 1 1) facets on the 2D Cu foil surface through cathodic corrosion, showing CH4 selectivity up to 69.6 %. Meanwhile, C2+ products became dominant with a selectivity up to 66 % on the same Cu (1 1 1) nanoparticles when supported on electrodeposited copper dendrites. The in-situ Raman spectroscopy indicated that the high CO coverage and local pH created by the hierarchical structure contributed to the product transformation from C1 to C2+. This study demonstrates that electrochemical processing could be employed as a promising method to control and tune the product selectivity of CO2 electroreduction.