Strontium-doped RuO electrocatalyst with abundant oxygen vacancies for boosting OER performance

The oxygen evolution reaction (OER) plays a crucial role as the anode reaction of electrolytic water splitting in various applications. To date, it is still a great challenge to develop highly active and durable electrocatalysts for acidic electrolytic water splitting. Herein, we highlight an effective strategy to regulate the oxidation state of Ru species and oxygen vacancies in RuO 2 by introducing Sr heteroatoms into its lattice based on the principle of charge equilibrium. The as-prepared Sr 0.1 RuO x catalyst exhibits excellent OER activity with an overpotential of 201 mV at a current density of 10 mA cm −2 , which is attributed to the higher proportion of Ru 4+ induced by Sr doping. Moreover, both experimental and theoretical calculations revealed that the introduced oxygen vacancies inhibited the overoxidation of Ru to Ru n >4+ during the OER process, thus enhancing the stability of Sr 0.1 RuO x . Therefore, the PEM electrolyzer using Sr 0.1 RuO x as the anode catalyst can be operated for 240 hours at 10 mA cm −2 without obvious attenuation. This work presents an effective strategy to regulate the structure of OER electrocatalysts with excellent performance. Sr 2+ doping in RuO 2 increases the proportion of oxygen vacancies and Ru 4+ , preventing formation of soluble Ru n >4+ species and lowering the Ru 4d band center, resulting in enhanced OER activity and stability in acidic media