A reconstructed porous copper surface promotes selectivity and efficiency toward C products by electrocatalytic CO reduction.

Electrocatalytic synthesis of multicarbon (C) products from CO reduction suffers from poor selectivity and low energy efficiency. Herein, a facile oxidation-reduction cycling method is adopted to reconstruct the Cu electrode surface with the help of halide anions. The surface composed of entangled Cu nanowires with hierarchical pores is synthesized in the presence of I, exhibiting a C faradaic efficiency (FE) of 80% at -1.