Potential-induced synthesis of cavity Cu2O/Cu nanocubes for enhanced electroreduced CO2 to C2+ products

Abstract

Electrochemical reduction reaction of CO₂ (CO₂RR) to C₁ and C₂ products can be achieved on Cu-based electrocatalysts. C₂ products exhibit higher energy density and economic value compared to C₁ products, making them more desirable as reduction products. However, the production of C₂ products on pure Cu catalysts involves multi-step proton-coupled electron transfer and C–C coupling steps, which are kinetically slow and result in poor catalytic activity and selectivity for the products. The cavity nanocubes Cu₂O(0.13-AA), Cu₂O(0.10-AA) and Cu₂O(0.15-AA) catalysts were synthesized via wet chemical reduction by adjusting the concentration of the reducing agent. The electrochemical pre-reduction method was used to obtain Cu₂O/Cu(0.13-AA), Cu₂O/Cu(0.10-AA) and Cu₂O/Cu(0.15-AA) catalysts for CO₂RR. Cu₂O/Cu(0.13 M-AA) catalyst achieves the high Faradaic efficiency (FE) of 39.98% for C₂H₄ and 54.76% for C₂ products (C₂H₄, C₂H₆, and C₂H₅OH), with significant inhibition of the hydrogen evolution reaction. In situ Raman experiments demonstrate that the cavity structure of the nanocubes enhances the local concentration of *CO intermediates, thereby promoting the C–C coupling process and improving the selectivity of CO₂ reduction to C₂ products.