| Semiconductor photocatalysis driven by solar light has great potential to eliminate organic pollutants in air and water rapidly, economically, and in an environmentally friendly manner, so it caused wide attention in the field of environmental pollution. Development of efficient photocatalyst is one of the important direction in current field of photocatalytic studies. Bi OBr is a novel semiconductor material, has shown excellent photoactivity in degradation of organic pollutants, attributed to its unique layered structure, indirect transition mode and suitable energy band structure. This paper focus on design and prepare the simulated sunlight photocatalytic activity of Bi OBr modification photocatalyst. By using a simple solvothermal route and photodeposition method, a series of Pt/Bi OBr powder photocatalyst were successfully fabricated. And Pt/Bi OBr film-coated optical fiber bundles were successfully fabricated by using a simple dip-coating and photodeposition method. Their phase and chemical structures, electronic and optical properties, textural properties as well as morphologies were well-characterized. The simulated sunlight photocatalytic performance including activity and stability of as-prepared Pt/Bi OBr powder and film were evaluated by selecting two typical light-insensitive organic pollutants, p-nitrophenol(PNP) and bisphenol A(BPA), as the target compounds. Moreover, photoelectrochemical experiments, as well ss free radical and hole scavenging experiments were applied to find out the photocatalytic mechanism.The main results was concluded as follows:1. A series of platinum deposited Bi OBr powder photocatalysts with different Pt loading were prepared by hydrothermal combined with photodeposition method with Bi(NO3)3?5H2O as Bi source and CTAB as Br source. Their phase and chemical structures, electronic and optical properties, textural properties as well as morphologies were well-characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), UV-Vis diffuse reflectance spectra(UV-Vis/DRS), transmission electron microscopy(TEM), field emission scanning electron microscopy(FESEM) and N2 adsorption/desorption. The characterized result showed that Bi OBr consists of numerous thin plates with(102) facet exposed dominantly, Pt particles homogeneously dispersed on the surface of Bi OBr nanoplates and Pt/Bi OBr favors to grow along(001) crystal facet. The BET surface area of Pt/Bi OBr increases with the Pt loading.Under simulated sunlight irradiation, Pt/Bi OBr-0.27 shows the highest photocatalytic activity toward the degradation of PNP. PNP is fully degraded after 60 min.2. The prepared Bi OBr-Si O2 suspension was used for coating optical fiber bundles by dip-withdrawn procedure, and then Pt deposited on Bi OBr film photocatalyst by photodeposition method. By carefully controlled the dip times and the amount ofH2 Pt Cl6?6H2O, Pt/Bi OBr film-coated quartz fiber bundles with different thickness and Pt loading have been obtained. The op tical absorption properties of the Pt/Bi OBr film was investigated by UV-vis/DRS. The simulated sunlight photocatalytic experiments shows that Pt/Bi OBr-0.22 film exhibited the highest photocatalytic activity in the degradation of BPA.BPA was fully degradated after irradiation for 90 min. And the degradation of BPA is still more than 95% after five consecutive tests. Additionally, the mechanism of photocatalytic degradation of aqueous organic pollutants over Pt/Bi OBr was revealed based on the photoelectrochemistry experiments and active species scavenging experiments. That is 1)optical fibers are not only the catalyst support but also the light transmitter, which increases the light utilization of Pt/Bi OBr film; 2) the synergistic effect of electron-sink function and localized surface plasmon resonance effect of Pt nanoparticles increases the light absorption and facilitates the separation of photogenerated electrons and holes, leading more active specious(h+and ?O2-) participated in the degradation progress. |
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