Preparation And Photocatalyticactivities Of Bi₃O₄Cl Based Composite Photocatalyst And Nano-Cu₂O

People faces the tremendous challenges of clean energy production and environmental pollution with the rapid development of economy in recent years. As an novel pollutants treatment technology with high efficiency, photocatalysis is considered as the most potential technology in wastewater treatment and air purification, which gains much attention. TiO2 is one of the most studied photocatalyst due to its characteristics of strong photoactivity, high stability and non-toxicity. Unfortunately, its wide application is restricted since TiO2 has a large band gap and its quantum efficiency is poor. Bismuth oxyhalide is a novel semiconductor photocatalyst with uniquely layered structure, which makes the semiconductor hold strong ability in separation of photogenerated charge carriers and subsequently induces its good photocatalytic activity. So Bismuth oxyhalide shows great potential in photocatalysis fields. In this dissertation, several studies were performed to improve the visible-light photocatalytic performance of Bi3O4Cl photocatalysts. In addition, we have prepared Cu2O and investigated its photocatalytic performance.First, we have synthesized a novel photocatalyst AgCl/Bi3O4Cl via a simple solid reaction method followed by ion exchange between Bi3O4Cl and AgNO3 solution. The stable dye Rhodamine B (RhB) aqueous solution is chosen as the model compound to estimate the photocatalytic activity of the composite. Various techniques were applied to study the probable photocatalysis mechanism of AgCl/Bi3O4Cl photocatalyst. The experimental result showed that 8% AgCl/Bi3O4Cl sample exhibits the highest photocatalytic efficiency. Meanwhile, the composite showed high stability. Thesynthesized AgCl/Bi3O4Cl exhibited stronger photocatalytic activity than pure Bi3O4Cl or AgCl under visible light irradiation because of the increased surface area, light harvesting ability and charge separation efficiency.Second, high-efficient Bi3O4Cl/g-C3N4 composite photocatalysts were synthesized using a simple calcination of Bi3O4Cl and g-C3N4. The prepared photocatalyst was characterized by techniques including BET, SEM, TEM, XRD, FT-IR, UV-vis and PL. The experiment results show that the decoration of Bi3O4Cl on g-C3N4 promoted the surface area of the photocatalyst, which enlarged the scope of the visible light absorption. What’s more, the formation of hetero-junction structure between Bi3O4Cl and g-C3N4 promoted the separation of electron-hole pairs and subsequently improved the photocatalytic performance of Bi3O4Cl/g-C3N4.Finally, we successfully prepared a novel photocatalyst, Cu2O by hydrothermal method at different temperature and hydrothermal time. It is observed that the catalyst prepared with different conditions shows different morphologyMeanwhile, the photocatalytic performances of the catalysts with different morphology were studied. Results indicated that the catalyst under the conditions of 16h、180 ℃ and 19h、140 ℃ exhibited better photocatalytic performance. The good photocatalytic performance of Cu2O is associated with its specific surface area and interface energy of lattice plane.