Breaking the Relation between Activity and Stability of the Oxygen-Evolution Reaction by Highly Doping Ru in Wide-Band-Gap SrTiO3 as Electrocatalyst

The creations of efficient electrocatalysts to accelerate the oxygen-evolution reaction (OER) has long been an objective to decrease the cost of renewable energy techniques. The activity and durability of an electrocatalyst are generally two competing properties, which scarcely coexist. To achieve a coincidence of activity and durability, strategies of hybrid heterostructures, composition modulation, and defect engineering have been widely investigated. As a highly active but poorly durable electrocatalyst, the perovskite SrRuO3 (SRO) encounters the specified dilemma, hampering its practical application. In this work, we applied another direction of material design, which adopted as its base the wide-band-gap semiconductor perovskite SrTiO3 (STO), which is highly stable in an alkaline medium. Through doping of Ru to extent similar to 30 atom % into STO, this solid-solution electrocatalyst can exhibit better OER performance and durability in comparison to SRO. With the information from the characterization of the electronic structures and the electrochemical measurement of Ru-doped STO as direct evidence, a lattice-oxygen-mediated mechanism synergistic with small resistivity increased the OER activity. A stable STO lattice matrix can also prevent the further decomposition of the perovskite structure, substantially extending the period of operation. Our work demonstrates that, through appropriate tuning of the chemical composition in wide-band-gap semiconductor oxides, a simultaneous improvement of electrocatalytic activity and durability is achievable.