Changing the Product Selectivity for Electrocatalysis of CO2 Reduction Reaction on Plated Cu Electrodes

Electrochemical reduction of carbon dioxide (CO2RR) on various types of Cu electrodes to useful chemicals and fuels has attracted much attention. Herein, we comparatively investigate the distributions of CO2RR products over electroplated Cu, chemically plated boron-doped Cu (Cu-B) and electroplated phosphorus-doped Cu (Cu-P) electrodes. A global Faradaic efficiency of more than 50 % can be reached for the C2+ (ethylene, ethanol and n-propanol) products on both plated Cu-B and Cu-P electrodes at similar to-1.15 V vs. RHE in 0.1 M KHCO3 electrolyte. Moreover, in situ surface enhanced infrared spectroscopy results together with quantitative analysis of the CO2RR products reveal a more facile conversion/depletion of the *CO intermediate after B- and P-doping, for which Cu-B promotes the C2+ products while Cu-P enhances both C2+ generation and CH4 evolution at faster *CO consumption. The present work suggests the vital role of *CO in the step of C-C bonding formation and highlights that the metalloid doping may alter the reactivity and selectivity of the intermediate.