Electrodeposition of Fractal Structured Nickel for Hydrogen Evolution Reaction in Alkaline

Abstract To accelerate the practical application of water splitting in alkaline media, it is imperative to enhance the electrocatalytic performance for the Hydrogen Evolution Reaction (HER). In this context, we demonstrate that a simple (one‐pot, one‐step) electrodeposition process of nickel (Ni) in the presence of 3,5‐diamino1,2,4‐triazole (DAT) results in the formation of fractally structured Ni films with a significantly increased surface area. The Electrochemically active surface area (ECSA) increases with the electrodeposition charge passed, with the film electrodeposited at 14 C cm −2 achieving a reduction in overpotential at −10 mA cm −2 ( η 10 ) to 65.7 mV, coupled with a remarkable increase in ECSA (114‐fold greater than that of Ni‐foil). Additionally, nickel deposited in the presence of DAT effectively mitigates deactivation during electrolysis, exhibiting a 3.6‐fold lower overpotential degradation compared to that of the smooth Ni foil. This simple electrodeposition technique, applicable to a variety of conductive substrates, is distinguished by its high catalytic performance in the HER, a feature of considerable significance.