In-situ constructing self-supported NiO/RuO₂ heterostructure for reinforced alkaline hydrogen evolution reaction

Rationally designing a strongly coupled heterostructure with rich functional sites and high catalytic stability is essential for efficient energy conversion. This work synthesizes a self-supported NiO/RuO₂ heterostructure for hydrogen production via facile dealloying following an in-situ electrochemical oxidation method. It only requires 88 ± 1 mV to drive a current density of -100 mA/cm² in the alkaline electrolyte during hydrogen evolution reaction (HER), outperforming NiO, RuO₂, and Pt foil. The higher anodic potential applied to the dealloyed ribbons results in lower overpotentials and faster reaction kinetics. Meanwhile, the catalytic activity and stability of the individual NiO can be significantly improved once coupled with a small amount of heterogeneous RuO₂. The strong synergistic effect between NiO and RuO₂ contributes to exposing abundant active sites, optimizing electronic structure, facilitating charge transfer at the interface, and most importantly, maintaining structural stability. These advantages make the self-supported NiO/RuO₂ heterostructure a promising candidate for replacing the Pt-based catalysts.