Manipulating Oxygen Vacancy in SrTiO₃ Nanoparticles to Achieve Enhanced Photoelectrochemical Performance in Water Splitting

Introducing oxygen vacancies into perovskite-type SrTiO3 nanoparticles usually takes dual or multiple steps, which are not conducive to subsequent modification and application. Herein, a facile nonstoichiometric method is applied to synthesize a series of oxygen vacancy (VO)-doped SrTiO3 (Sr1–XTiO3–δ) as a photoanode material in photoelectrochemical (PEC) water-splitting reactions. Experimental results reveal a nonlinear relationship between the PEC performance and VO concentration in SrTiO3 nanoparticles. Sr1–XTiO3–δ doped with an appropriate amount of VO can significantly enhance its light response and electrocatalytic activity. The optimal Sr0.95TiO3–δ demonstrated the best PEC activity with an incident photon-to-current conversion efficiency of 3.144 times higher than that of pristine SrTiO3. Enhanced PEC activity is attributed to superior light absorption and retarded photogenerated charge carrier recombination. This work systematically reveals the role of oxygen vacancies in SrTiO3 nanoparticles for achieving enhanced PEC performance in water splitting, which may offer inspiration for defect engineering of perovskite oxides.