Synergistic Cu@Ni–N–C Yolk@Shell Nanostructure Catalyst for Selective Acetonitrile Electroreduction to Ethylamine

Abstract Electrochemical upgrading, such as acetonitrile (CH ₃ CN) reduction to ethylamine (CH ₃ CH ₂ NH ₂ , EtNH ₂ ), represents a promising route for the mild synthesis of value‐added chemicals with renewable energy sources. However, a lack of an in‐depth understanding of the hydrogenation mechanism hinders the rational development of efficient electrocatalysts to boost EtNH ₂ electrosynthesis. Here, an innovative confinement strategy is reported to an efficient yolk@shell‐structured Cu@Ni–N–C catalyst, comprising inner Cu nanorods and outer atomically‐dispersed Ni on a nitrogen‐doped carbon layer, for high‐performance electrochemical CH ₃ CN reduction toward CH ₃ CH ₂ NH ₂ generation. The introduction of Ni–N–C tailors the electronic structure of Cu, and more importantly, turns its reaction pathway from a direct electroreduction (DER) mechanism into a more favorable electrochemical hydrogenation (ECH) mechanism, where ^* H intermediate is first generated at outer Ni–N–C layer through the proton‐coupled electron transfer process and then interacts with the adsorbed CH ₃ CN molecules at inner Cu nanorods. As a consequence, the kinetic energy barrier of electrochemical CH ₃ CN reduction is significantly reduced, thereby leading to a boosted activity, selectivity, and stability of Cu@Ni–N–C electrocatalyst with respect to bare Cu counterpart. This work provides insights into the rational design of synergistic yolk@shell catalysts for multi‐step electrochemical upgrading reactions with an optimized hydrogenation mechanism.