Sulphur anion induced electronic structure regulation of RuO2 nanodots for efficient electrocatalytic overall water splitting

Abstract

Developing bifunctional electrocatalysts with enhanced efficiency for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) remains a significant challenge. Herein, we constructed S-doped ultra-fine RuO₂ nanodots that were uniformly dispersed on carbon nanotubes. The incorporation of S effectively induces local rearrangement of the electronic structure of RuO₂, thereby enhancing the dispersion of RuO₂ as active sites and optimizing the adsorption free energy of H* intermediate. As expected, the as-synthesized S-RuO₂/CNT delivers remarkable HER activity in all pH electrolytes, achieving lower overpotentials of 136, 159, and 396 mV at 100 mA cm⁻² in acidic, neutral, and basic solutions, respectively. Moreover, a unitary S-RuO₂/CNT electrolytic cell requires only a lower voltage (1.476 V) to achieve a current density of 10 mA cm⁻² in 1.0 mol/L KOH. This ingenious work represents a significant breakthrough in the rational design of bifunctional electrocatalysts, enabling remarkable performance in electrochemical water electrolysis.