Neighboring Cationic Vacancy Assisted Adsorption Optimization on Single-Atom Sites for Improved Oxygen Evolution

Single-atom catalysts with particular electronic and geometric microenvironments provide an atomic-scale perspective for research into the mechanism of catalysis. Designing the neighboring geometry of single-atom catalysts can tailor the adsorption configuration of reaction intermediates and enhance their activity in catalytic reactions. In this work, we proposed a neighboring cationic vacancy strategy in single-atom Ru catalysts to adjust the adsorption configuration of reaction intermediates for improved oxygen evolution performance. An Ru single-atom catalyst with neighboring Co2+ vacancies (Ru1/VCo-Co(OH)2) showed better OER performance than a catalyst without Co2+ vacancies (Ru1/Co(OH)2). The mass activity of Ru1/VCo-Co(OH)2 was calculated to be 6688 A g–1 at 300 mV overpotential, which was 4.73 times higher than that of Ru1/Co(OH)2. Particularly, the mass activity of Ru1/VCo-Co(OH)2 was notably 481.15 times higher than that of commercial RuO2. Both in situ ATR-FTIR spectroscopy measurements and DFT calculations manifested that the existence of neighboring Co2+ vacancies modulated the adsorption configuration of *OOH intermediates on atomic Ru sites by hydrogen bonding, which reduced the energy barrier of rate-determining steps and improved the OER activity.