Photocatalytic Performance Of Doped And Modiifed BiQBr Composites

With the rapid development of the industry, industrial pollution becomes a serious problemin the world. The application of photocatalysts for wastewater treatment has recently attractedconsiderable attention because the solar energy can be available as energy source. Especially, thesemiconductor photocatalysts, including BiOX (X=Cl, Br, I), TiO2or ZnO, exhibit higherphotocatalytic activity and stability under UV and visible light irradiat.on. However, the pureBiOBr photocatalysts still can not meet the requirements of practical application due to theinconvenience to separate, low stability for reuse and photocatalytic efficiency. The compositeBiOBr photocatalysts prepared by doping or/and modification methods have been considered thepromising candidates for removal of organic pollutants. According to above background, themain contents of the dissertation are listed as following:1. The Mn-doped BiOBr crystals have been prepared by solvothermal method usingmanganese acetate (Mn(CH3COO)2·4H2O) as doped resource and bismuth nitrate(Bi(NO3)3·5H2O) as Bi resource. The research results showed that the Mn elements were enteredinto the lattice of BiOBr. Some position of Bi elements in BiOBr lattice had been replaced byMn. The resultant composite photocatalysts exhibited higher photocatalytic activity under visiblelight in degradation of Rhodamine B (RhB), attributing to the improvement of thephoto-absorption property and the separation efficiency of photogenerated electrons and holes.The holes and O2are the main active species in aqueous solution under visible light irradiation,rather than OH.2. In order to improve the stability and convenience to separate, the carbon nanofibers havebeen firstly prepared by carbonization of polyacrylonitrile (PAN) nanofibers. Then, theBiOBr/AgBr hybrids with flower-like nanosheet structure could be further immobilized on thesurface of carbon nanofibers by a facile solvothermal route. The morphologies, structuralproperties, and photocatalytic activities of the resultant products were investigated. At the sametime, it also proves that the final removal of organic pollutants from solutions is caused byphotocatalytic degradation rather than by sorption. Furthermore, the three-dimensional (3D) BiOBr/AgBr hybrid structure can capture light from all directions, thus showing potential forapplication in places with high albedo (high fraction of reflected radiation). This work mayprovide new insights into preparing other inorganic photocatalytic fibers and may extend theirpotential applications for degradation of organic pollutants.