Cu‐Mo Plasmonic Coupling Generates Enhanced Local Electromagnetic Fields in Co 0.5 Cu 0.5 /Mo Heterostructures for Photocatalytic Ammonia Borane Hydrolysis

Abstract

ABSTRACT Plasmon‐mediated catalysis provides a promising route for enhancing photocatalytic hydrogen generation from ammonia borane (NH 3 BH 3 ), yet the reaction rate remains limited by insufficient charge generation and separation. Herein, we address this limitation by developing a plasmonic coupling strategy to generate enhanced local electromagnetic fields in a ternary Co 0.5 Cu 0.5 /Mo. Cu nanoparticles are dispersed on Mo and Co nanosheets are anchored on Mo and extend toward the Cu nanoparticles. Co 0.5 Cu 0.5 /Mo catalyst achieves an outstanding turnover frequency of 162.8 min −1 under steady‐state H 2 flow for photocatalytic NH 3 BH 3 hydrolysis at 298 K, outperforming Co/Mo and Cu/Mo by factors of approximately 1.5 and 5.0, respectively, and surpassing most reported noble‐metal‐free catalysts under comparable conditions. Combined spectroscopic characterizations, surface enhanced Raman scattering, in situ x‐ray photoelectron spectroscopy, and theoretical calculations reveal that the synergistic plasmonic coupling between Mo with a partially oxidized surface and Cu intensifies the local electromagnetic field, promotes charge generation and separation, and induces preferential electron accumulation on Cu. This redistribution enlarges the electron density difference between Cu and Co active sites, thereby facilitating the activation of NH 3 BH 3 and H 2 O and accelerating hydrogen evolution. This study provides a feasible strategy for engineering electromagnetic‐field‐enhanced non‐precious‐metal catalysts for NH 3 BH 3 hydrolysis and related hydrogen‐generation reactions.