Preparation and photocataytic property of Sr0.25Bi0.75O1.36 photocatalyst

Abstract The present paper reports a novel visible light-driven photocatalyst, Sr 0.25 Bi 0.75 O 1.36 prepared by a simple impregnation–calcination method. Brunauer–Emmett–Teller analysis, scanning electron microscopy, X-ray diffraction, Raman spectroscopy, diffuse reflectance spectroscopy and density functional theory were applied to investigate the physical/photophysical properties and electronic structure of the catalyst. The photocatalytic activity of Sr 0.25 Bi 0.75 O 1.36 was evaluated by the decomposition of methylene blue (MB) in an aqueous solution under visible light irradiation (λ > 420 nm). Pure Sr 0.25 Bi 0.75 O 1.36 is found to possess an optical band gap of 2.43 eV and exhibit excellent photocatalytic activity for MB photodegradation. The theoretical calculations show that the electronic structure of the photocatalyst favors the mobility of photo-generated charge carriers and positively contributes to the photocatalytic reaction. The good photoabsorption and special electronic structure are believed to be the origin of the high activity of the photocatalyst.