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

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 Cu_xO is significant for achieving high-efficiency catalytic performance and excellent stability. Herein, amorphous Cu_xO nanoparticles embedded uniformly in mesoporous silica spheres (Cu_xO@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 Cu_xO 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 Cu_xO@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, Cu_xO@mSiO₂ maintains stable catalytic activity and selectivity over 9 h of continuous eCO₂RR reaction.