CuO doping SiO2 for enhancing electron transfer to product C2H4 in electrocatalytic CO2 reduction

Abstract

The electrocatalytic CO₂ reduction reaction (CO₂RR) offers a promising pathway for carbon cycling and high-value fuel synthesis. However, the efficient production of ethylene (C₂H₄), a critical multicarbon product, remains constrained by insufficient catalyst activity and selectivity. Although copper-based materials enable C–C coupling, conventional CuO catalysts suffer from imbalanced *CO intermediate adsorption strength and sluggish charge transfer kinetics‌.In this study, a silica (SiO₂) doping strategy was employed to synergistically modulate the electronic structure and surface active site distribution of CuO, significantly enhancing CO₂-to-C₂H₄ conversion efficiency. Experimental results demonstrate that SiO₂ incorporation induces local electronic density rearrangement around Cu²⁺, stabilizing *CO adsorption, while the constructed Cu-O-Si interfaces accelerate charge transfer, enhances electron transfer and reduce the energy barrier for *COCHO formation. The optimized SiO₂-10 %/CuO catalyst achieves a C₂H₄ Faraday efficiency of 42 % and a partial current density of 6.3 mA/cm² at −1.4 V (vs. RHE), representing a threefold improvement over pristine CuO. Notably, the catalyst exhibits exceptional stability over 4 hours‌.Structural characterization and theoretical calculations reveal that SiO₂ doping promotes the self-assembly of CuO nanosheets into flower-like architectures with a high specific surface area and exposes synergistic (111)/(002) facets, which collectively enhance *CO intermediate enrichment and directional coupling‌. This work provides novel insights into designing high-performance CO₂RR catalysts through multidimensional modulation strategies.