Spillover‐Mediated H* Redistribution Promotes Electrocatalytic Acetonitrile Hydrogenation in PEM Reactors

Electrocatalytic acetonitrile hydrogenation (EAH) provides a sustainable route for ethylamine synthesis, yet suffers from low productivity, competitive hydrogen evolution reaction (HER), and high energy consumption due to suboptimal catalyst and reactor design. To overcome these challenges, we describe a palladium-copper hybrid catalyst that employs spillover-mediated active hydrogen (H*) redistribution mechanism. Hydrogen spillover from palladium with high H* coverage to copper with low H* coverage creates H* redistribution: reduced H* coverage of Pd mitigates HER while maintaining efficient EAH, and increased H* availability of Cu promotes EAH without activating stagnant HER. Integration of these catalysts into both cathode and anode of a proton exchange membrane electrolyzer enabled efficient ethylamine electrosynthesis and formic acid electrooxidation over 100 h, achieving exceptional ethylamine productivity (6160.0 ± 119.1 mmol g_cat ^-1 h^-1) and Faradaic efficiency (94.2 ± 1.6%) at record-low energy consumption (3.55 kWh kg_ethylamine ^-1). This work marks a critical advancement toward sustainable ethylamine electrosynthesis.