Ethanol assisted cyclic voltammetry treatment of copper for electrochemical CO2 reduction to ethylene

Renewable energy driven electrocatalytic reduction of carbon dioxide into fuels and chemicals is one of the promising methods to achieve carbon neutrality. However, the development of high activity and selectivity catalysts remains a great challenge. Herein, we report the cyclic voltammetry (CV) treatment of copper with a mixed aqueous electrolyte solution of KOH and ethanol to obtain highly porous nanoparticle structures (Cu–KOH/Ethanol-CV). The as-obtained catalyst achieves a Faradaic efficiency (FE) of 42.1% for ethylene production with a partial current density of −15 mA/cm2 in an H-cell, and a FE of C2H4 of 48.4% at the current densities of −200 mA/cm2 in a flow cell. Our results demonstrate that the enhanced C2H4 production in electrocatalytic CO2 reduction is not only correlated to the increase of electrochemically surface area but also to the extensive exposure of defect sites. Our work provides a new and facile approach for designing efficient catalysts for C2H4 production in electrocatalytic CO2 reduction. [Display omitted] •Highly porous nanostructures were obtained through a CV treatment method with mixed aqueous solution of ethanol and KOH.•High FE(C2H4) of 42.1% in an H-cell and 48.4% at the current density of -200 mA cm-2 in a flow cell were achieved.•The correlation between roughness of electrode and ethylene production for electrocatalytic CO2 reduction was revealed.•Defect sites on the surface of copper played an important role in promoting ethylene selectivity.