Enhancing the photocatalytic activity of Ruddlesden-Popper Sr₂TiO₄ for hydrogen evolution through synergistic silver doping and moderate reducing pretreatment

The photocatalytic hydrogen (H₂) generation relies heavily on the properties of photocatalysts, including their light absorption, charge transport, and oxygen vacancy of photocatalysts. In this work, we have successfully synthesized Ruddlesden-Popper perovskite Sr₂TiO₄ as photocatalysts for H₂ evolution reaction. Importantly, we adopted a facile and effective strategy of Ag doping and reducing pretreatment to tailor the properties of Sr₂TiO₄ photocatalysts. The synergistic effect of Ag doping and moderate reducing pretreatment confers Sr₂TiO₄ photocatalyst with improved morphological characteristics, increased specific surface area, optimized light absorption capability, and bandgap, suppressed charge carrier recombination, as well as an increased amount of surface oxygen vacancies. Benefiting from these merits, r-Ag_0.05Sr_1.95TiO₄ with a suitable amount of Ag doping and moderate reducing pretreatment displays an excellent photocatalytic performance for H₂ generation, which presents average H₂ production rates of 1695 μmol h⁻¹ g⁻¹ and 541 μmol h⁻¹ g⁻¹ under full-range light irradiation (λ ≥ 250 nm) and visible light irradiation (λ ≥ 400 nm), respectively.