Synthesis And The Photocatalytic Performances Of One-dimensional Bismuth Based Oxide, Halogen Oxide Heterojunction

With the rapid development of economy, energy crisis and environmental pollution has caused worldwide concern. How to solve these problems has become academic research focus. Current research show that the photocatalytic technology will be the best and “green” way to solve these two problems. Therefore, we mainly design and synthesize one dimensional bismuth-based oxide and oxyhalide heterojunction photocatalysts in this thesis. The main contents are as follows:1. WO3-Bi2WO6 heterostructures were synthesized by a facile hydrothermal method using WO3 nanorods and Bi(NO3)3 solution as raw materials. The Bi2WO6 nanosheets uniformly anchored on the surface of WO3 nanorods. The photocatalytic activity of the samples was assessed for degradation of Rhodamin B(Rh B) and phenol under solar light irradiation. The WO3-Bi2WO6 heterostructures showed higher photocatalytic activities than pure WO3 and Bi2WO6. As the content of Bi2WO6 increases, the photocatalytic activity of WO3-Bi2WO6 heterojunction enhanced and the optimal sample was WO3-Bi2WO6 with the mole ratio n WO3 : n Bi3+ of 5:3. The efficient separation of electron-hole pairs because of the stagger band potentials between WO3 and Bi2WO6 may account for the higher photoactivity of WO3-Bi2WO6 hybrid structures. Radical scavenger experiments indicate that holes(h+) and superoxide radicals(·O2-) were the main active species for Rh B degradation during photocatalytic process.2. One-dimensional(1D) Bi12O17Br2/Bi24O31Br10 type Ⅱheterostructures were synthesized by calcining the Bi OBr/Bi(OHC2O4)·2H2O heterostructures in air at 400 oC. The photocatalytic activity of the samples was assessed for degradation of Rhodamin B(Rh B) and phenol under visible light irradiation. The Bi12O17Br2/Bi24O31Br10 hierarchical heterostructures show enhanced visible light catalytic activity with the loaded/Bi24O31Br10 contentincreasing. The efficient separation of electron-hole pairs because of the staggered band potentials between Bi12O17Br2 and Bi24O31Br10 may account for the high photoactivity of Bi12O17Br2/Bi24O31Br10 hybrid structures. Radical scavenger experiments confirm that photogenerated holes(h+) are the main active species to react directly with Rh B molecules during photocatalytic process.3. p-Bi2O3/n-Zn O heterojunction photocatalysts have been successfully synthesized by hydrothermal method using Bi2O3 nanorods as precursors. The p-Bi2O3/n-Zn O heterojunction exhibited excellent photocatalytic activity for the degradation of methylene blue(MB) and phenol under visible light irradiation.. The formation of p-n junctions between Bi2O3 and Zn O can form an interior electric field in their interface, which can improve the efficient separation and transfer of electron-hole pairs and then enhance the photocatalytic activity of p-Bi2O3/n-Zn O heterojunction photocatlyst.