Building of Amorphous CuxO With Cu─O─Si Interface for CO2 Reduction to C2+ Products.

Abstract

Amorphous copper-based catalysts with a large number of undercoordination sites exhibit promising catalytic performance for the electrocatalytic CO2 reduction reaction (eCO2RR). However, their structure stability of amorphous CuxO is significant for achieving high-efficiency catalytic performance and excellent stability. Herein, amorphous CuxO nanoparticles embedded uniformly in mesoporous silica spheres (CuxO@mSiO2) were fabricated via a modified Stöber method combined with in situ electrochemical pre-reduction. Experimentally, the Cu─O─Si interface suppresses the over-reduction of CuO to metallic Cu and modulates the electronic structure of Cu species. It can be demonstrated that the resulting amorphous CuxO switches the adsorption of *CHO and *OCCO intermediates from conventional Cu-anchoring configurations to lattice oxygen-anchoring counterparts, significantly weakening the thermodynamic restriction for post-CO coupling toward C2+ pathway. Ideally, the CuxO@mSiO2-0.4 catalyst achieves a C2+ Faradaic efficiency of 40.1% with a partial current density of -10.8 mA∙cm-2 at -1.7 V vs. RHE, which is two times greater than that of crystalline CuO-derived Cu. Furthermore, CuxO@mSiO2 maintains stable catalytic activity and selectivity over 9 h of continuous eCO2RR reaction.