Fabrication of Highly Active Ag3PO4/ZnO/Diatomite for Visible Light Photocatalytic Degradation of Tetracycline Hydrochloride

A novel Ag3PO4/ZnO/diatomite composite photocatalyst was prepared by simple ultrasonic dispersion-precipitation method. The structure, composition, microstructure and optical properties of the catalysts were characterized by means of X-ray diffraction (XRD), fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscope (TEM) and UV-vis diffuse reflectance spectra (UV-vis DRS). Moreover, the visible light catalytic performance of the catalyst was investigated with tetracycline hydrochloride (TC) as the degradation target. The results showed that the photocatalytic activity of Ag3PO4/ZnO/diatomite in the degradation of TC, which can reach 90.99% removal rate of 30 mg/L TC under visible light, was significantly better than that of monomer catalysts and Ag3PO4/ZnO catalyst. Meanwhile, it exhibited better stability compared with pure Ag3PO4. The improvement of visible light catalytic activity and stability of Ag3PO4/ZnO/diatomite is mainly attributed to the catalyst’s better adsorption capacity, wider spectral response range, more efficient photo-generated electrons and holes migration and less photocorrosion. The results of free radical trapping experiments show that the main active species of the reaction system are h+ and •O2−.