Abstract: A series of WO₃/ZnO composite photocatalysts with different WO₃ concentrations were prepared by a precipitation-grinding method followed by calcination at different temperatures. The prepared samples were characterized by N₂ physical adsorption, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, UV-visible spectroscopy, and photoluminescence spectroscopy. The photocatalytic activity of the samples was evaluated by photocatalytic degradation of acid orange II under UV light (λ = 365 nm) irradiation. The results showed that at the optimal calcination temperature of 600 °C, the WO₃/ZnO composite photocatalyst with 2 wt% concentration of WO₃ showed about doubled photocatalytic activity compared to pure ZnO. The increase in the photocatalytic activity could be attributed to the coupling of WO₃, which suppressed the growth of ZnO particles, increase of the surface area and increased amount of surface OH groups of the sample. The presence of WO₃ also restrained the recombination rate of e^-/h⁺ pairs.

Key words: tungsten oxide, coupling, zinc oxide, photocatalysis, acid orange II