Mediation of Electrocatalytic CO ₂ Reduction by Electrodeposited Cu ₂ O@Cu Hierarchical Polyhedrals

Abstract In this work, we demonstrated Cu 2 O@Cu hierarchical structures for electrocatalytic CO 2 reduction reactions (CO 2 RR). The electrocatalysts were achieved by a one‐step electrodeposition method, in which the compositional ratios and surface morphologies could be engineered by simply varying the operative parameters including the precursor concentration, deposition temperature, deposition time and deposition voltage. At optimal conditions, a total Faradic efficiency of 73.0% toward C 1 products including HCOOH and CO was attained. The electrocatalytic mechanism was then explored, where the Cu‐OH ad intermediates adsorbed at the Cu 2 O surfaces during the electrodeposition process were transformed into Cu 0 that was capable of mediating the electrocatalytic CO 2 RR performances.