Oxygen vacancy-rich Nd-doped RuO2 for efficient acid overall water splitting

The development of highly active and acid-stable Ru-based electrocatalysts is of great significance for water electrolysis but remains a huge challenge due to serious Ru corrosion in an acid medium. Herein, we prepared oxygen vacancy (O_V)-rich Nd-doped RuO₂ nanocrystals by facile synthesis via hydrothermal and subsequent annealing for efficient overall water splitting. The catalyst exhibits an overpotential of only 200 mV for OER and 44 mv for HER at the current density of 10 mA cm⁻² in 0.5 M H₂SO₄ electrolyte. Nd-doped RuO₂ only demands a cell voltage of 1.52 V to drive the overall water splitting reaction and displays excellent stability for 100 h. Density functional theory further revealed that the newly constructed Nd-doped RuO₂ sites activate the difficult to react *O intermediates, reducing the adsorption energy of the OER intermediates to effectively minimize the Gibbs free energy (*O to *OOH) of the reaction rate-determining step and regulate the center of the active site d-band. The synergistic effect of aliovalent doping and vacancy engineering contributes to the excellent electrocatalytic performance of Nd-doped RuO₂. This performance control strategy can pave the way for the development of effective and economically viable catalysts.