A facile synthesis of g-C3N4/BaTiO3 photocatalyst with enhanced activity for degradation of methylene blue under visible light

g-C3N4/BaTiO3 composite was hydrothermally synthesized at 200°C for 24 h from a dispersed mixture of g-C3N4 and BaTiO3 in water, in which BaTiO3 was hydrothermally synthesized at 200°C for 48 h using barium nitrate, isopropanol, titanium tetrachloride and sodium hydroxide as precursors without assistance of any surfactant; and graphitic carbon nitride (g-C3N4) was prepared by pyrolysis of melamine at 520°C. The obtained materials were characterized by X-ray diffraction, infrared spectra, scanning electron microscopy, elemental mapping, X-ray photoelectron spectroscopy and ultraviolet–visible diffuse reflectance spectroscopy. The photocatalytic activity of the materials was assessed by degradation of methylene blue (MB) under visible light. The enhancement of photocatalytic activity of the g-C3N4/BaTiO3 composite compared to the single components, g-C3N4 and BaTiO3 was observed, which is attributed to the reduction of combination rate of photogenerated electron–hole pairs in the composite. The MB degradation over the composite was mainly attributed to the photoreduction process induced by the superoxide radical anions (•O2−) and hydroxyl radicals (•OH); and a mechanism was also proposed based on the heterojunction model from the two semiconductor components.