Enhanced photocatalytic performance of Z-scheme TiO2/g-C3N4 heterojunction towards degradation of Rhodamine B

Abstract

Nanoflower-like rutile TiO2 was synthesized by hydrothermal method and graphitic carbon nitride (g-C3N4) was prepared by thermal polycondensation of thiourea. Z-Scheme TiO2/g-C3N4 photocatalysts with different mass ratios were prepared via a simple physical mixing method. The crystal structure, morphology, chemical states and optical properties of the samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and UV–vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity of catalysts was evaluated by the degradation of Rhodamine B (RhB) under simulated solar irradiation. Compared with pure g-C3N4 and TiO2, all TiO2/g-C3N4 composites exhibited higher photocatalytic activity, and the highest photocatalytic degradation efficiency of 95 % was achieved when the mass ratio of TiO2 and g-C3N4 was 1:3. The enhanced photocatalytic activity of the TiO2/g-C3N4 composites was attributed to the formation of Z-scheme heterojunction between g-C3N4 and TiO2.