High capable visible light driven photocatalytic activity of WO3/g-C3N4 hetrostructure catalysts synthesized by a novel one step microwave irradiation route

Abstract

In this paper, WO3/graphitic carbon nitride (g-C3N4) composite photocatalyst were successfully synthesized using microwave irradiation method followed by annealing process at 400 °C for 2 h. Powder X-ray diffraction, Raman and transmission electron microscope results suggest that both pure and composite samples showed hexagonal-phase WO3 (JCPDS Card No. 83-950) with particle size around in 30–40 nm. The optical band gap and specific surface area of the g-C3N4/WO3 composites were in the range of 2.55–2.78 eV and 45–87 m2/g, which is confirmed through UV–Vis diffuse reflectance (DRS) and N2 nitrogen absorption–desorption analysis. The photocatalytic activity of the photocatalysts was investigated by degradation of congo-red (CR) and malachite green (MG) under induced visible light irradiation. The results showed that WO3/g-C3N4 nanocomposite with a mass ratio of 1:3 (W1G3) showed the highest photocatalytic activity efficiency (93%) and high stability (only loss 3%) towards CR. The improved photocatalytic activity of the g-C3N4/WO3 composites is due to the synergistic effect of g-C3N4 and WO3 was considered to lead to improved photogenerated carrier separation. A possible degradation mechanism of CR over the g-C3N4/WO3 composite photocatalyst under visible light irradiation was also proposed.