Promoting Hydrogen\nEvolution Reaction in Acidic and\nNeutral Conditions on Co-Based Ternary Electrocatalyst: Enhancing\nCatalytic Activity via Electrochemical Oxidation

Water electrolysis presents significant potential for\nthe sustainable\nproduction of green hydrogen. However, its widespread adoption faces\nseveral challenges, primarily the high cost and limited availability\nof Pt-group metal catalysts. To address this challenge, researchers\nhave investigated high-performance catalysts based on affordable transition\nmetals. One such catalyst that has attracted attention is CuCoMo,\nknown for its notable activity and stability in the hydrogen evolution\nreaction (HER) under alkaline conditions. In this study, we presents\nan electrodeposited CuCoMo catalyst that is also effective for HER\nunder both acidic and neutral conditions. The catalytic performance\nwas significantly enhanced through electrochemical oxidation. This\npost-treatment process alters the structure and chemical state of\nthe catalyst surface, enhancing its effectiveness in promoting HER\nunder acidic and neutral environments. The modified catalyst demonstrated\noverpotentials of 25 and 28 mV, achieving a current density of 10\nmA cm<sup>–2</sup> in acidic and neutral conditions, respectively.\nFurthermore, the catalyst’s performance was assessed in a single\ncell, where it achieved a current density of 1.05 A cm<sup>–2</sup> at 2.0 V using deionized water as the feedstock. The catalyst exhibited\nsuperior HER activity in both half-cell and single-cell evaluations,\nhighlighting its potential as efficient alternative to Pt for practical\nwater electrolyzers.