Efficient photocatalytic hydrogen production over solid solutions Sr1-xBixTi1-xFexO3 (0 ≤ x ≤ 0.5)

Abstract

Constituting solid solutions for prototype perovskite compound SrTiO3 offers appealing means to tailor the optical and photocatalytic properties of this wide band gap semiconductor. Here we successfully synthesized a series of Sr1-xBixTi1-xFexO3 (0≤x≤0.5) solid solutions via hydrothermal method. Their crystal structures, surface nature and other physicochemical properties were systematically explored. Our results show that a large portion of BiFeO3 (up to 50%) can be incorporated into the structure SrTiO3 without symmetry degradation from cubic. A number of important factors such as microstructures, light absorbance and surface hydrophilicity are all strongly correlated with Bi/Fe content in the solid solutions. Photocatalytic performance was greatly improved after formation of solid solutions and high activity normally occurs in samples with large surface area, high crystallinity as well as absence of Bi (V) species. The highest activity belongs to sample Sr0.6Bi0.4Ti0.6Fe0.4O3 with photocatalytic hydrogen production rate ∼50μmol/h under full range irradiation and ∼5μmol/h under visible light irradiation, corresponding to apparent quantum efficiency ∼0.63% and 0.11%, respectively. Theoretical calculation reveals the critical role of Fe in constituting spin-polarized bands inside the intrinsic band gap of SrTiO3, therefore is responsible for band gap reduction and visible light activities. This work highlights the benefits of forming solid solutions in the design and development of efficient photocatalysts.