Evoking C2+ production from electrochemical CO2 reduction by the steric confinement effect of ordered porous Cu2O

Abstract

Selective conversion of carbon dioxide (CO₂) to multi-carbon products (CO₂-to-C₂₊) at high current densities is in essential demand for the practical application of the resultant valuable products, yet it remains challenging to conduct due to the lack of efficient electrocatalysts. Herein, three-dimensional ordered porous cuprous oxide cuboctahedra (3DOP Cu₂O–CO) were designed and synthesized by a molecular fence-assisted hard templating approach. Capitalizing on the merits of interconnected and uniformly distributed pore channels, 3DOP Cu₂O–CO exhibited outstanding electrochemical CO₂-to-C₂₊ conversion, achieving faradaic efficiency and partial current density for C₂₊ products of up to 81.7% and −0.89 A cm⁻², respectively, with an optimal formation rate of 2.92 mmol h⁻¹ cm⁻² under an applied current density of −1.2 A cm⁻². In situ spectroscopy and simulation results demonstrated that the ordered pores of 3DOP Cu₂O–CO can effectively confine and accumulate sufficient *CO adsorption during electrochemical CO₂ reduction, which facilitates efficient dimerization for the formation of C₂₊ products. Furthermore, the 3DOP structure induces a higher local pH value, which not only enhances the C–C coupling reaction, but also suppresses competing H₂ evolution.