Photocatalytic splitting of water under visible-light irradiation over the NiOx-loaded Sm2InTaO7 with 4f-d-d configuration

A new visible-light-response photocatalyst Sm₂InTaO₇ with 4f-d¹⁰-d⁰ configuration crystallized in a cubic system with the space group Fd3m was synthesized by a solid-state reaction method. NiOx-loaded Sm₂InTaO₇ showed high photocatalytic activities for H₂ evolution from pure water under visible light irradiation (λ>400 nm). Changes in the photocatalytic activity with the calcination temperature of Sm₂InTaO₇ and the amount of NiOx loaded indicated that the combination of highly crystallized Sm₂InTaO₇ and a high dispersion of NiOx particles led to high photocatalytic activity. The high photocatalytic performance of NiOx-loaded Sm₂InTaO₇ supported the existing view that the photocatalytic activity correlated with the lattice distortion. Density functional theory calculation indicated that strong dispersion from the hybridized In 5s 5p orbitals at the bottom of the conduction band was responsible for the high activity of photocatalyst Sm₂InTaO₇.