Facile One-Step Hydrothermal Fabrication of (Sr0.6Bi0.305)2Bi2O7/SnO2 Heterojunction with Excellent Photocatalytic Activity.

The pyrochlore-type (Sr_0.6Bi_0.305)₂Bi₂O₇ (SBO), containing Bi³⁺ and Bi⁵⁺ mixed valent states, was recently found to be used as a new visible light responsive photocatalyst. Novel SBO/SnO₂ heterostructured composites were synthesized through a facile one-step hydrothermal method. The phase structure, morphology, chemical composition, and optical properties of the obtained samples were characterized by XRD, SEM, TEM, XPS, and UV-vis DRS. Compared to pure SBO and SnO₂, the synthesized SBO/SnO₂ composites exhibited significantly enhanced photocatalytic efficiency. The results indicated that the photoinduced holes and superoxide radicals play a dominant role and are the main reactive species during the degradation of Methylene Blue (MB) solution under visible light irradiation. Heterojunctions, formed in samples, directly contribute to the improvement of photocatalytic efficiency of SBO/SnO₂ composites, since it not only broadens the light response range, but also accelerates the separation of photogenerated carriers. [ABSTRACT FROM AUTHOR]