MoN Supported Pt Nanocluster Catalysts with Regulated Interfacial Water Structures for Boosting Alkaline Hydrogen Oxidation Reaction

Abstract The development of nanocluster electrocatalysts is a promising way to simultaneously improve atomic utilization and catalytic reactivity of noble metals. Although precisely controlled nanocatalysts with exact atomic composition and well‐defined structures have been widely investigated for various electrocatalytic reactions, the origin of their excellent performance has been mainly focused on the thermodynamic energetics of key intermediates. The relationship between the structure of nanoclusters and the electric‐double‐layer (EDL) environment formed at the interface between electrode and electrolyte has been largely overlooked. Herein, MoN‐supported Pt nanocluster catalysts are synthesized with a remarkable intrinsic activity of 1.927 mA cm⁻² toward alkaline hydrogen oxidation reaction (HOR). Electrochemical experiments, in situ surface‐enhanced infrared absorption spectroscopy, and theoretical calculations verify the coordination environment, charge redistribution, and band structures of Pt nanoclusters are conducive to providing optimized adsorption energy for the vital hydroxyl intermediates. Furthermore, it is found that the adsorbed hydroxyl species can promote the proportion of water molecules in the gap region and mitigate the discontinuity of the hydrogen‐bond network in the EDL, thereby providing more hydrogen transfer channels to accelerate the overall reaction kinetics. This work uncovers the optimization of thermodynamic energetics and interfacial microenvironment induced by metal nanoclusters, shedding light on the rational design of highly effective alkaline HOR catalysts.