Decorating Cu Nanoparticles with Pd Clusters for Enhanced Nitrile Electro-Hydrogenation to Primary Amines by Effective Hydrogen Spillover

The H2O-participating electrochemical hydrogenation (ECH) of benzonitrile represents a mild and efficient method for benzylamine synthesis, but the kinetics and Faraday efficiency are still limited. Herein, the developed Pd clusters dispersed Cu nanoparticles encapsulated in porous carbon (Pdn-Cu@C) achieves efficient ECH of benzonitrile (C6H5CN) to benzylamines (C6H5CH2NH2). In situ infrared spectroscopy and theoretical studies reveal that the Pd/Cu interface functions as the active site for active hydrogen (*H) generated by H2O dissociation, enhances the adsorption of C6H5CN, and weakens the adsorption of C6H5CH2NH2. Moreover, the Gibbs free energy barriers for *H spillover are much lower than that of *H self-coupling. As expected, Pdn-Cu@C exhibits efficient electro-hydrogenation of C6H5CN with the conversion of 97.42%, a high C6H5CH2NH2 selectivity of 97.21%, and Faradaic efficiency of 92.10% under a specific voltage. This finding blazes a feasible trail to suppress the competitive *H self-coupling and offers insights for multistep protonation ECH reactions.