Influence of Fe composition in metal foam substrate on OER performance of jet-electrodeposited Ni Co alloy electrodes

Developing low-cost and efficient electrocatalysts for the oxygen evolution reaction (OER) is essential to produce green hydrogen for the decarbonization of the industry or heavy-duty applications. In this study, Ni Co alloy electrodes for alkaline water electrolysis were fabricated via scanning jet electrodeposition, using porous Ni Fe substrates with varying Fe content. To understand the role of substrate composition, the influence of Fe concentration on electrode morphology and OER performance was systematically investigated. The results showed that increasing the Fe content in the substrate led to the formation of finer and denser micro-nanoparticle structures on the Ni Co alloy surface, which is favorable for catalytic activity. The different substrate compositions affected the deposition structure of the alloy, thereby altering the bubble contact angle of the electrode surface. Among them, the Ni Co alloy electrode prepared on the Ni/Fe = 0.14:1 substrate exhibited better hydrophilicity with a bubble contact angle of 29.8°. Enhanced OER activity was observed with increasing Fe content; the electrode on Fe foam showed a low overpotential of 247 ± 3.02 mV vs RHE at 10 mA cm −2 . The novelty of this work lies in the scanning jet electrodeposition strategies for different substrate compositions to control the nucleation, which leverages the Fe content of the porous Ni Fe substrate to directly control the Ni Co alloy electrode's nucleation, microstructure, and wettability without additives or post-treatment. This coupling between substrate compositions and scanning jet electrodeposition provides a simple, scalable, and cost-effective method for improving OER activity. Our results demonstrate that substrate composition is an effective design control method for fabricating Ni Co electrodes with high OER performance. • Ni Co OER electrodes made by scanning jet deposition on Ni Fe foams. • Fe-rich substrates yield finer Ni Co nanostructures and better wettability. • Fe-foam electrode shows 247 ± 3 mV@10 mA cm −2 and enhanced OER activity.