Preparation And Photocatalytic Activities Of Iron Vanadium, Iron Molybdate And Cadmium Vanadate Doped G-C₃N₄

Since the seventy’s of last century, semiconductor photocatalysis has become one of the hotspot in scientific research. In order to make full use of solar energy, many scientists pay attention to develop new photocatalyst material with visible light response. g-C3N4 is a novel organic polymer semiconductor and attract much attention due to the advantages of visible light responsibility, good chemical and thermal stability, non-toxic and easy preparation, etc. Hence, g-C3N4 shows great potential in photocatalysis. This paper is mainly to promote the photocatalytic activity of g-C3N4 via the coupling of FeVO4, Fe2(MoO4)3, and CdV2O6, and prepare three composite semiconductor photocatalysts with high efficiency.Firstly, we have prepared a novel FeVO4/g-C3N4 composite catalyst by the milling and calcination method. The photocatalytic testing indicates that the synthesized sample presents high photoactivity in RhB degradation under visible light irradiation. Through a series of characterizations of the composite catalyst, the increased photocatalytic activity is ascribed to the formation of FeVO4/g-C3N4 heterojunction, which promotes the separation of electron hole pairs effectively. Moreover, the FeVO4 content is found to be an important factor affecting the catalyst activity, when the FeVO4 content is 5.0wt%, the composite shows the highest photocatalytic activity.Secondly, the g-C3N4/Fe2(MoO4)3 composite photocatalyst was prepared by a grinding and calcination method. The prepared sample can absorb the light with a wavelength of less than 560nm, indicating its excellent light absorbption ability. Under visible light irradiation,10.6wt% g-C3N4/Fe2(MoO4)3 composite photocatalyst displays the best photocatalytic activity.The main reason is attributed to the suitable band potentials g-C3N4 and Fe2(MoO4)3, Which triggers the formation of g-C3N4/Te2(MoO4)3 heterojunction and retards the recombination of electron and hole and extends the service life of the carrier, thereby improves the photocatalytic activity.Finally, the CdV2O6/g-C3N4 composite catalysts were prepared by the same method. The photocatalytic activity of the composite was investigated via RhB degradation under visible light irradiation. The strcture, surface area, morphology, and optical properties of the composite were investigated via X-ray powder diffraction (XRD), N2 adsorption (BET), Fourier transform infrared spectroscopy (FT-IR), UV vis diffuse reflectance spectroscopy (UV vis DRS), thermogravimetry (TG), scanning electron microscopy (SEM), transmission electron microscopy (TEM). The results show that CdV2O6/g-C3N4 catalyst exhibits high photocatalytic activity, and good stability. A reasonable explanation about the high photoactivity of the composite was suggested based on the characterization results.