Steering C-N coupling pathway on spatial-separated zinc dual sites for efficient oxime electrosynthesis.

Abstract

Multi-step cascade reactions that couple electrochemical and non-electrochemical steps are an appealing strategy for designing efficient reactions. However, their development is fundamentally constrained by mechanistic uncertainty, leading to uncontrolled side reactions. Herein, a spatially separated active-site strategy is developed, using the electrosynthesis of cyclohexanone oxime (CHO) as a model, to bias the reaction toward the interface confinement pathway via a designed Zn-based mixed-site catalyst. Based on controlled experiments, in situ characterization and theoretical calculations, we demonstrate that the Zn single-atom and Zn nanoparticle site can adsorb N-containing intermediates and cyclohexanone (CYC), respectively. It is demonstrated that 99.5% cyclohexanone conversion, 50.3% cyclohexanone oxime Faradaic efficiency, 100% carbon selectivity, and 41.0% nitrogen selectivity can be achieved, while maintaining performance stability over 200 h. Detailed mechanistic analysis indicates that at suitable Zn single-atom and nanoparticle ratio, interfacial hydrogen-bond network of water is optimized, which can modulate both adsorption orientation and coverage of *CYC and the coverage of N-containing intermediates to enhance the desired reaction pathway.