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

Abstract

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-Ag0.05Sr1.95TiO4 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.