Tailoring Co Site Reactivity via Sr and Ni Doping in LaCoO3 for Enhanced Water Splitting Performance

Perovskite oxides (ABO3) featuring rare-earth cations in the A-site and first-row transition-metal cations in the B-site, have emerged as promising catalytic materials for addressing the slow kinetics of the water splitting reaction. In this study, we synthesized La1-xSrxCo1-yNiyO3 using the solution combustion synthesis method and conducted a comprehensive investigation into the structural, surface, and electronic properties of the resulting materials. The strategic doping of Sr in La sites and Ni in Co sites has notably enhanced the kinetics and effectiveness of both the oxygen evolution reaction at the anode and the hydrogen evolution reaction at the cathode, leading to an overall improvement in water splitting efficiency over La1-xSrxCo1-yNiyO3. Detailed mechanistic studies have revealed the crucial role of high covalency and surface oxygen vacancies, tailored through aliovalent doping, in enhancing the catalytic activity of the oxygen evolution reaction in La1-xSrxCo1-yNiyO3. This research serves as a pioneering effort to establish a correlation between electronic and surface properties and to elucidate the mechanistic aspects of water splitting over perovskite materials.