The Study Of Preparation And Properties Of Having A Heterojunction Structure Or Dominant Crystal Facets Photocatalyst

The global energy shortage and environmental pollution issues, nowadays, have been becoming intractable problems the world facing. Semiconductor-based photocatalysts have attracted extensive interest and have been regarded as one of the effective solutions to the current problems of the energy and environment. TiO2 is a famous semiconductor owning good photocatalytic activities for the oxidative degradation of organic compounds. However, TiO2 has poor nature solar efficiency and slow reaction rate, which hinders its further applications.In this study, a novel ZnS/ZnWO4 nanocomposite photocatalyst was synthesized through a facile hydrothermal synthesis method. And the ZnS/ZnWO4 nanocomposite shows an enhanced photocatalytic activity for the degradation of rhodamine B (RhB) under simulated solar light. The results show that ZnS/ZnWO4 nanocomposite photocatalysts have better photocatalytic activity than the single ZnWO4 or ZnS. In the case of ZnS compounding, ZnS/ZnWO4 photocatalyst led to the lower recombination ratios of photo-generated electron hole pairs and then higher photocatalytic performance. In addition, it has the potential to become a useful technology for environmental cleanup without secondary pollution.In this study, C3N4/Zn1-xCdxS (O?x?1) heterostructures with adjustment of the band gap were successfully prepared by calcination and a hydrothermal synthesis method. The photocatalytic properties of C3N4/Zn1-xCdxS composite photocatalysts were evaluated by the photocatalytic degradation of RhB under visible light irradiation. The results showed that the combination of the two semiconductor photocatalysts (C3N4 and Zn1-xCdxS) greatly enhanced the photocatalytic degradation efficiency of RhB compared to the pure C3N4 and Zn1-xCdxS under visible light irradiation. Among them, the 0.1 C3N4/Zn0.8Cd0.2S composite photocatalyst exhibited the highest photocatalytic activities with the degradation efficiency of RhB arriving to 97.9% within 90 min. The remarkable photocatalytic activity of the 0.1 C3N4/Zn0.8Cd0.2S composite photocatalyst was mainly attributed to the appropriate band structure and the effective separation of photogenerated electron-hole pairs. Additionally, a possible basic mechanism of the composite semiconductor photocatalytic process was also discussed. Moreover, it was also investigated that O2·- and h+ were the main reactive oxidative species in this photocatalytic process of the degradation of RhB on the 0.1 C3N4ZZn0.8Cd0.2S heterostructure photocatalyst.A novel heterojunction photocatalyst CdWO4/BiOBr was fabricated with nano-rod cadmium tungstate (CdWO4) hybridized by flake-like BiOBr through hydrothermal and chemical precipitation method. Moreover their photocatalytic activities were evaluated by decomposing dye molecule RhB under visible light irradiation, and their high photocatalytic performance was reveled, and 15% CdWO4/BiOBr composite with p-n heterojunction structure was recorded to be the best sample owning highest activity. The results of the study concluded that it was the introduction of BiOBr into the catalyst that mainly enhanced the activity of the photocatalyst by promoting the separation of electron-hole group on the interface of BiOBr and CdWO4.In this study, the Ag3PO4 microcrystal was successfully prepared at different temperatures using precipitation and hydrothermal methods. It was found that the synthesized temperature had some effects on the morphologies and photocurrent of Ag3PO4. As the synthesized temperature increased from 20? to 120 ?, the ratio of exposed (110) facets increased, which are the active photocatalysis facets in Ag3PO4 crystals, along with a higher photocatalytic efficiency over RhB under visible light irradiation. And the Ag3PO4 microcrystals synthesized at 120? exhibited the highest photocatalytic activities with the degradation ratio of RhB rising up to 97.83% in 6 min due to the high separation efficiency of electron and hole pairs. In addition, the main active species and their roles were investigated by adding scavengers (isopropyl alcohol and EDTA) during the photocatalytic degradation of RhB and a possible mechanism was discussed.