Preparation of graphitic carbon nitride (g-C₃N₄)/WO₃ composites and enhanced visible-light-driven photodegradation of acetaldehyde gas.

Novel visible-light-driven graphitic carbon nitride (g-C₃N₄)/WO₃ composite photocatalysts were prepared, and the acetaldehyde (CH₃CHO) degradation activity of these composites was evaluated. The prepared g-C₃N₄/WO₃ composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible diffuse reflection spectroscopy (UV-vis), and the N₂ gas adsorption Brunauer-Emmett-Teller (BET) method (N₃-BET). The WO₃ particles, which were 100-300 nm in size, were in direct contact with the g-C₃N₄ sheet surface. The optical band gap and specific surface area of the g-C₃N₄/WO₃ composites were in the range of 2.65-2.75 eV and 4-7 m(2)/g, respectively. The g-C₃N₄/WO₃ composites exhibited higher activity for the photodegradation of CH₃CHO under visible light irradiation compared to g-C₃N₄. The optimal WO₃ content for the CH₃CHO photodegradation activity of the heterojunction structures was determined. The synergistic effect of g-C₃N₄ and WO₃ was considered to lead to improved photogenerated carrier separation. A possible degradation mechanism of CH₃CHO over the g-C₃N₄/WO₃ composite photocatalyst under visible light irradiation was proposed. These results should usefully expand applications of g-C₃N₄ as a visible-light-driven photocatalyst.