Novel photocatalyst, Bi2Sn2O7, for photooxidation of As(III) under visible-light irradiation Original Research Article

Nanocrystalline Bi2Sn2O7, a visible-light photocatalyst synthesized via a facile hydrothermal route, is used to remove arsenite from aqueous solution for the first time. The as-synthesized Bi2Sn2O7 product is characterized by X-ray diffraction, N2 sorption–desorption, UV–vis diffuse reflectance spectroscopy, transmission electron microscopy, electron spin resonance, X-ray photoelectron spectra, and electrochemistry technology. The results reveal that the sample has an average particle size of approximately 10 nm, a specific surface area of 51.3 m2/g, and a band gap of 2.88 eV. Moreover, the Bi2Sn2O7 nanoparticles exhibit a high photocatalytic activity in the oxidation of As(III) (up to 96.8%) under visible-light irradiation. radical dotO2− and h+ are recognized as the primary active species responsible for As(III) oxidation. Meanwhile, a possible mechanism for the photo-oxidation of As(III) over Bi2Sn2O7 is also proposed.