The Preparation And Capacity Of Photocatalyst On The Basic Of Bi₂₅FeO₄₀, Bi₂WO₆

This thesis focuses on the application of semiconductor material in photocatalytic degradation, introducing the advantages and disadvantages of it. And describes the reaction and structure of semiconductor photocatalyst, as well as the main factors which affected its capacity in detail. Moreover, the modification technology of semiconductor photocatalyst utilized on domestic and foreign was also discussed in this thesis, and then analysis the preparation for the multibasic oxide semiconductor photocatalyst. In the above basis, we made a research direction, taking iron oxalate and Bi2W06 as objects, on prepare efficient photocatalyst through hydrothermal. The productions are as follows:1. A novel metal-organic compound[Fe(ox)(phen)]n(phen=1,10-Phennannthroline, ox=oxalate acid) has been hydrothermally synthesized and structurally characterized by X-ray single-crystal diffraction, X-ray diffraction, IR, Uv-vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The compound crystallizes in monoclinic, space group P21 with a=0.92289(3) nm, b=1.35719(3)nm, c=1.02012(4) nm,β=94.372(2)°,V=1.27402(8)nm3,Z=2,and exhibits a 2D layer structure. The photocatalytic activities of the compound were evaluated by decomposing rhodamineB (RhB) and methyl orange (MO) under visible light irradiation. In addition, the mechanism of the photocatalytic properties was proposed.2. Novel nanoparticle-assembled Bi2sFeO40 (BFO) tetrahedrons with relatively good dispersion were success-fully synthesized through a facile, mild and rapid hydrothermal process. The phases and morphologies of the samples were characterized by powder X-ray diffraction (XRD), energy dispersive spectroscopy (EDS),X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM) andscanning electron microscopy (SEM). Such sillenite-type BFO tetrahedrons were found to be fabricated byabundant nanoparticles with single crystalline nature. Some influencing factors including reaction time,temperature and the amount of additives (e.g., polyacrylamide, sodium citrate and sodium hydroxide) wererevealed to play crucial roles in the generation of this BFO nanoarchitecture. Moreover, the visible light-driven photocatalytic activities of the BFO products were investigated.3. Based on the rational design of heterojunction interface, a novel and efficientBi 2sFeO 40-Bi2WO6 heterostructure photocatalyst was successfully constructed by a facilehydrothermal process, using pre-fabricated Bi2WO6 nanoflakes as Bi3+ source and thesecond-phase material. The as-prepared photocatalyst was characterized by powder X-raydiffraction (XRD), FT-IR spectrum, energy dispersive spectrometry (EDS), X-ray photoelectronspectrum (XPS), high resolution transmission electron microscopy (HRTEM) and scanningelectron microscopy (SEM). The photocatalytic performance of the Bi25FeO40-Bi2W06heterostructure under the UV-visible light irradiation was investigated, which showed that suchBi25FeO40-Bi2WO6 heterojunction possessed higher photocatalytic ability than the mechanicalmixing product and the single-phase sample (Bi2sFe04oandBi2W06). This enhancedphotocatalytic efficiency might be attributed to the matching band positions, close interfacialconnection, and "face-to-face" contact mode of heterojunction interface. In addition, a possiblephotocatalytic decomposition mechanism and the separation process of photoinduced electronsand holes were discussed at length.