Preparation and Visible Light Photocatalytic Activity of Hollow Tubular g-C3N4/Ag3PO4 Composite Catalyst

Hollow tubular g-C3N4/Ag3PO4 composite catalyst was prepared by chemical precipitation method. The structure, morphology, and optical properties of the composite catalyst were characterized by X. ray diffraction (XRD), scanning electron microscopy (SEM), UV. Vis diffuse reflectance spectroscopy (UV. Vis DRS), and fluores. cence emission spectroscopy. The results showed that Ag3PO4 nanoparticles can be uniformly dispersed on the surface of hollow tubular g-C3N4, and closely combined to form a heterojunction. The photocatalytic activity of the composite catalyst under visible light irradiation was studied by the degradation of tetracycline hydrochloride (TC). The results showed that the degradation rate of TC over the hollow tubular g-C3N4/Ag3PO4 composite catalyst was 98% within 80 min, and its degradation reaction rate constant was three times that of pure Ag3PO4. After five cycles, the degradation rate of TC by the composite catalyst maintained 87%, indicating excellent stability. The capture experiment showed that hole (h(+)) and superoxide anion (center dot O-2(-)) were the main active species in the photocatalytic reaction. Based on the energy band theory, the Z. scheme photocatalytic mechanism of g-C3N4/Ag3PO4 composite catalyst heterojunction was proposed