Thermal evaporation-driven fabrication of Ru/RuO2 nanoparticles onto nickel foam for efficient overall water splitting

Abstract

Developing high-performance bifunctional electrocatalysts towards the hydrogen evolution reaction/oxygen evolution reaction (HER/OER) holds great significance for efficient water splitting. This work presents a two-stage metal–organic thermal evaporation strategy for the fabrication of Ru-based catalysts (Ru/NF) through growing ruthenium (Ru)/ruthenium dioxide (RuO₂) nanoparticles (NPs) on nickel foam (NF). The optimal Ru/NF shows remarkable performance in both the HER (26.1 mV) and the OER (235.4 mV) at 10 mA cm⁻² in an alkaline medium. The superior OER performance can be attributed to the synergistic interaction between Ru and RuO₂, facilitating fast alkaline water splitting. Density functional theory studies reveal that the resulting Ru/RuO₂ with the (110) crystal surface reinforces the adsorption of oxygen on RuO₂, while metallic Ru improves water dissociation in alkaline electrolytes. Besides, Ru/NF requires only 1.50 V at 10 mA cm⁻² for overall water splitting, surpassing 20 wt% Pt/C/NF||RuO₂/NF. This work demonstrates the promising potential of a thermal evaporation approach for designing stable Ru-based nanomaterials loaded onto conductive substrates for high performance overall water splitting.