SrTiO3-CaCr0.5Nb0.5O3 Solid Solutions as p-Type Photocatalysts for Z-Scheme Water Splitting under Visible Light Illumination

Abstract P-type semiconductivity has been observed in solid solution series (SrTiO3)1-x(CaCr0.5Nb0.5O3)x (0.0 ≤ x ≤ 0.15), which all adopt cubic symmetry and own intense absorption in the visible light region. These solid solutions are superior H2 evolution photocatalysts under visible light illumination (λ ≥ 400 nm). An AQE as high as 1.02% at 420 ± 20 nm has been achieved at optimal composition (SrTiO3)0.85(CaCr0.5Nb0.5O3)0.15 which significantly surpass the parent compounds. Stoichiometric H2/O2 production under visible light illumination has been successfully realized using Z-scheme system containing (SrTiO3)0.85(CaCr0.5Nb0.5O3)0.15, WO3 and I-/IO3- redox couple.