A defect-rich silver electrode with nickel hydroxide nanoparticles for alkaline hydrogen evolution reaction

The development of a hydrogen evolution reaction (HER) catalyst with low-cost, high activity and long-term durability is essential for industrial water electrolysis. In this work, a rapid and scalable technique, cold-press, was engineered to fabricate silver/nickel hydroxide (Ag/Ni(OH)₂) electrodes for catalyzing the alkaline HER. Owing to the defect-rich Ag substrate and abundant Ag/Ni(OH)₂ interfaces, the self-supported catalyst shows high activity and long-term durability, with an overpotential of 66 mV at 10 mA cm^-2 (in 1 M KOH) and excellent durability during 200 h of continuous reaction at 100 mA cm^-2. Moreover, kinetic isotope effect (KIE) and tert-butanol (TBA) quenching experiments reveal that the high performance arises from accelerated water dissociation at the Ag/Ni(OH)₂ interface and optimized hydrogen adsorption/desorption in the defect-rich silver matrix. Our work demonstrates that the cold-press process is a versatile strategy toward highly efficient and stable alkaline HER catalysts for industrial applications.