Synthesis, Property Characterization and Photocatalytic Activity of the Novel Composite Polymer Polyaniline/Bi₂SnTiO₇

Abstract: A novel polyaniline/Bi₂SnTiO₇ composite polymer was synthesized by chemical oxidation in-situ polymerization method and sol-gel method for the first time. The structural properties of novel polyaniline/Bi₂SnTiO₇ have been characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray spectrometry. The lattice parameter of Bi₂SnTiO₇ was found to be a = 10.52582(8) Å. The photocatalytic degradation of methylene blue was realized under visible light irradiation with the novel polyaniline/Bi₂SnTiO₇ as catalyst. The results showed that novel polyaniline/Bi₂SnTiO₇ possessed higher catalytic activity compared with Bi₂InTaO₇ or pure TiO₂ or N-doped TiO₂ for photocatalytic degradation of methylene blue under visible light irradiation. The photocatalytic degradation of methylene blue with the novel polyaniline/Bi₂SnTiO₇ or N-doped TiO₂ as catalyst followed first-order reaction kinetics, and the first-order rate constant was 0.01504 or 0.00333 min⁻¹. After visible light irradiation for 220 minutes with novel polyaniline/Bi₂SnTiO₇ as catalyst, complete removal and mineralization of methylene blue was observed. The reduction of the total organic carbon, the formation of inorganic products, SO₄²⁻ and NO₃₋, and the evolution of CO₂ revealed the continuous mineralization of methylene blue during the photocatalytic process. The possible photocatalytic degradation pathway of methylene blue was obtained under visible light irradiation.