Novel SrTiO3/NaTaO3 and visible-light-driven SrTiO3/NaTaO3:N nano-heterojunctions with high interface-lattice matching for efficient photocatalytic removal of organic dye

Abstract

SrTiO₃/NaTaO₃ (STO/NTO) heterojunction photocatalysts were successfully constructed by decorating NaTaO₃ nanocubes with SrTiO₃ nanoparticles via a hydrothermal method. The structure of the perovskites NaTaO₃ and SrTiO₃ bear some resemblance to each other, which increases the interface lattice match for promoting the migration of photogenerated carriers between the STO/NTO interfaces. In comparison to pristine NaTaO₃ and SrTiO₃ samples, the STO/NTO composites exhibited remarkably improved capacity for the degradation of rhodamine B (RhB) under ultraviolet (UV) light (λ < 400 nm) irradiation. Furthermore, the partial replacement of O²⁻ by N³⁻ in the TaO ₆ octahedron narrowed the band gap of NaTaO₃, which significantly enhanced the photocatalytic performance of the SrTiO₃/NaTaO₃:N (STO/NTON) heterojunction under visible light (λ > 400 nm). Finally, the possible band structures of the STO/NTO and STO/NTON photocatalysts were proposed, which indicated that an n–n type heterojunction was constructed with a staggered gap for fast separation of photogenerated electron–hole pairs.