Strontium doping RuO2 electrocatalyst with abundant oxygen vacancies for boosting OER performance

Oxygen evolution reaction (OER) plays a crucial role as the anode reaction of electrolytic water in various applications. To date, it is still a great challenge to develop highly active and durable electrocatalysts for acidic electrolytic water. Herein, we highlight an effective strategy to regulate the oxidation state of Ru species and oxygen vacancies in RuO2 by introducing Sr heteroatom into its lattice based on the principle of charge equilibrium. The as-prepared Sr0.1RuOx exhibits excellent OER activity with an overpotential of 201 mV at the current density of 10 mA cm-2, which should be ascribed to the higher proportion of Ru4+ induced by Sr doping. Moreover, both experimental and theoretical calculations revealed that the introduced oxygen vacancies inhabited Ru to be overoxidized to Run>4+ during the OER process, thus enhancing the stability of Sr0.1RuOx. Therefore, the PEM electrolyzer by using Sr0.1RuOx as the anode catalyst can be operated for 240 hours at 10 mA cm-2 without obvious attenuation. This work presented an effective strategy to regulate the structure of the OER electrocatalysts with excellent performance.