SrTiO3-CaCr0.5Nb0.5O3 solid solutions as p-type photocatalysts for Z-scheme water splitting under visible light illumination

P-type semiconductivity has been observed in solid solution series (SrTiO 3 ) 1- x (CaCr 0.5 Nb 0.5 O 3 ) 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 H 2 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 (SrTiO 3 ) 0.85 (CaCr 0.5 Nb 0.5 O 3 ) 0.15 which significantly surpasses the parent compounds. Stoichiometric H 2 /O 2 production under visible light illumination has been successfully realized using Z-scheme system containing (SrTiO 3 ) 0.85 (CaCr 0.5 Nb 0.5 O 3 ) 0.15 , WO 3 and I − /IO 3 − redox couple.