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

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.