Two-step electrodeposition of NiMo@Ni nanostructures as an effective electrocatalyst for hydrogen evolution in an alkaline medium

Abstract

Earth-abundant metallic materials offer a promising alternative to noble metal-based electrocatalysts for hydrogen production with NiMo alloys are emerging as strong candidates. This study investigates a two-step electrodeposition of NiMo@Ni nanostructures onto nickel foam (NF) using sulfate-based alkaline bath. The morphology, microstructure, and composition of the electrocatalysts were systematically characterized using a field emission scanning electron microscope (FE-SEM), a confocal laser scanning microscope (CLSM), and an energy dispersive X-ray spectrometer (EDS). Results showed the hierarchical micro/nanostructure and alloying increased the electrochemically active surface area, enhanced intrinsic electrocatalytic activity, and improved surface wettability, resulting in outstanding electrocatalytic performance. Under optimized conditions, overpotentials of 100 mV and 245 mV are required to achieve current densities of 10 and 100 mA cm⁻², respectively, along with a Tafel slope of 50 mV dec⁻¹. Furthermore, the potential showed minimal variation during the stability test, confirming the excellent electrocatalytic stability of the synthesized electrode. This study presents a rational and cost-effective approach for synthesizing high-performance HER electrocatalysts based on NiMo micro/nanostructure.