Nanostructured catalyst-layer generation on binary Fe-Ni alloys for efficient and anti-corrosion oxygen evolution reaction

Summary Fe-based alloys are promising low-cost anodes for alkaline water electrolysis. However, their activation proceeds through corrosive surface reconstruction, and the relationship between activity and durability remains unresolved. Here, we investigate the potential-cycling-induced formation of nanostructured catalyst layers on binary Fe-Ni alloys across the full composition range and elucidate the interplay among alloy composition, catalyst-layer structure, Fe dissolution, and oxygen evolution reaction performance. Potential cycling generates a stacked-nanosheet NiFe (oxy)hydroxide layer whose thickness and Ni content increase with substrate Ni fraction, while Fe dissolution decreases monotonically. Notably, under identical potential cycling and at similar Ni contents, Fe-Ni alloys exhibit nearly an order of magnitude lower Fe dissolution than austenitic stainless steels, demonstrating superior corrosion resistance. These findings establish binary Fe-Ni alloys as low-Ni, corrosion-resistant anodes that combine high intrinsic activity with reduced metal dissolution, offering a rational pathway toward durable and cost-effective electrodes for alkaline water electrolysis.