Engineering Ni _x Cu _(100‐x) @Ni Electrocatalysts on Microwave‐Reduced Ni/C for Efficient Hydrogen Evolution Reaction

ABSTRACT

In this study, a novel synergistic three‐layer architecture‐comprising a microwave‐reduced Ni/C base, an electrodeposited Ni interlayer, and a bimetallic Ni–Cu top coat (Ni ₃₀ Cu ₇₀ /Ni/M)‐was designed for the hydrogen evolution reaction (HER) in alkaline media. Structural characterization by X‐ray diffraction (XRD) confirmed the formation of a highly crystalline Ni–Cu alloy, while scanning electron microscopy (SEM) and energy‐dispersive X‐ray (EDX) spectroscopy revealed morphological evolution and surface oxidation. The catalyst initially exhibited a low Tafel slope of approximately 79.4 mV dec ⁻¹ , suggesting a mechanism under mixed Volmer–Heyrovsky control. However, chronoamperometric tests at −0.3 V (vs. RHE) over 60 h showed a gradual increase in catalytic activity, suggesting a surface reconstruction process. The integration of structural and electrochemical data indicates stable HER performance over the tested 60‐h period. The findings demonstrate that surface engineering enhances catalytic efficiency in alkaline water electrolysis, emphasizing its significance for optimizing catalysts in practical applications. The findings provide a promising basis for future catalyst development.