Substrate Dependent Electrodeposition of Ni–Co Alloy for Efficient Hydrogen Evolution Reaction

Nickel–cobalt alloys are electrodeposited on different substrates (copper, stainless steel and mild steel) adopting cyclic voltammetry approach. Structural studies confirm the formation of face-centred cubic phases of Ni–Co alloy on all three substrates. Different morphologies of Ni–Co such as spheres and aggregated particles are observed when deposited on different substrates. The anodic and cathodic peaks of Ni–Co alloys are observed at 0.15, 0.3 V, 1.2 V and 1.3 V (vs. RHE) in case of all the three substrates. Overpotential for Ni–Co electrodeposited on Cu (Ni–Co/Cu) is the lowest ƞ = −131 mV (vs. RHE) at 10 mA/cm 2 compared to other two electrodes due to the porous morphology and higher electroactive surface area than the other electrodes. Tafel slope of Ni–Co/Cu (−193 mV/dec) is found to be lowest, among all three electrodes. The stability analysis of 12 h reveals that the Ni–Co/Cu is most stable compared to other electrodes. Hence, Ni–Co alloys deposited on copper substrate can be a suitable choice for electrochemical hydrogen generation by water splitting. Graphical abstract