Preparation and Photocatalytic Activity of Co3O4/g-C3N4 Composite Photocatalysts via One-Pot Synthesis

A series of Co3O4/g-C3N4 composite photocatalysts were prepared by a one-pot method using melamine and cobalt chloride hexahydrate as raw materials. The structure and optical properties of the synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) and photoluminescence spectrum (PL). The photocatalytic activities of Co3O4/g-C3N4 composites were evaluated by using tetracycline hydrochloride(TC) as a model pollutant under visible light irradiation. The results indicated that Co3O4/g-C3N4 composite photocatalysts were porous structures with high specific surface area, which have significant light absorption in visible light region. The in situ generated Co3O4 nanoparticles can form heterojunctions on the surface of g-C3N4, which can effectively transfer the photon-generated carriers and decrease the recombination rate of electrons and holes, thus the photocatalytic activity can be efficiently improved. Besides, there was an optimal amount of Co3O4 for the Co3O4/g-C3N4 composite photocatalysts. When the adding amount of cobalt chloride hexahydrate was 8% (wlw) of melamine, the obtained composite photocatalyst (CoCN-8) showed the highest photocatalytic performance and the degradation of TC can reach 85% within 60 min under visible light irradiation. However, in the same condition, the degradation of TC can only reach 23% by pure g-C3N4 photocatalyst.