Lewis Acidic Support Boosts C-C Coupling in the Pulsed Electrochemical CO₂ Reaction

Copper-oxide electrocatalysts have been demonstrated to effectively perform the electrochemical CO2 reduction reaction (CO2RR) toward C2+ products, yet preserving the reactive high-valent CuOx has remained elusive. Herein, we demonstrate a model system of Lewis acidic supported Cu electrocatalyst with a pulsed electroreduction method to achieve enhanced performance for C2+ products, in which an optimized electrocatalyst could reach similar to 76% Faradaic efficiency for C2+ products (FEC2+) at similar to-0.99 V versus reversible hydrogen electrode, and the corresponding mass activity can be enhanced by similar to 2 times as compared to that of conventional CuOx. In situ time-resolved X-ray absorption spectroscopy investigating the dynamic chemical/physical nature of Cu during CO2RR discloses that an activation process induced by the KOH electrolyte during pulsed electroreduction greatly enriched the Cu5+O/Zn5+O interfaces, which further reveals that the presence of Zn5+O species under the cathodic potential could effectively serve as a Lewis acidic support for preserving the Cu5+O species to facilitate the formation of C2+ products, and the catalyst structure-property relationship of Cu5+O/Zn5+O interfaces can be evidently realized. More importantly, we find a universality of stabilizing Cu5+O species for various metal oxide supports and to provide a general concept of appropriate electrocatalyst-Lewis acidic support interaction for promoting C2+ products.