The Modification And Application Of New-type Nano-photocatalyst Of BiOCl

Nitrophenols are toxic to humans, animals and plants, and are listed as “priority pollutant” by the Environmental Protection Agency(EPA) of USA. Unfortunately, it is common to detect nitrophenols in aquatic environment and even in drinking water.Therefore, a facile process for easy removal of nitrophenols is urgently required for water treatment. Owing to effectively, rapidly and environmentally friendly,semiconductor photocatalysis have became the main techniques to remove the pollutants. However, the low solar energy conversion efficinency and the high recombination rate of photogenerated electrons and holes limit its practical applications.From the preparation of the new and high-performance photocatalysts(Bi OCl),following research work based on two aspects. Though the BiOCl shows a better photocatalysis efficiency on the organic matters, he still owes a wide band gap(3.2-3.6 eV), so causing the low quntum efficiency and high recombination rate of photogenerated electrons and holes, which limits its application. So the starting point of this article is: The fist one is making efforts to decrease the high recombination rate of photogenerated electrons and holes using the carbon quntum dots doping which can work as an electron acceptor. This work also studied on the different influence of imparity particle size distribution of CQDs for the dopping. The other is to develop a new heterogeneous materials to overcome the wide band gap and only for the responsing of ultraviolet light through the method of improment of surface defect,while introducing the reduced graphene oxide to enhance the photocatalytic performance of the composite material. The details are summarized as follows:(1) Preparation and research of Carbon quntum dots/BiOCl nanocomposites(CQDs/BiOCl). BiOCl was prepared by Room Temperature Method in the presence of bismuth nitrate pentahydrate and potassium chloride; using the hydrothermal method to synthesis the high fluorescence and water solubility of Carbon quntum dots,controlling the different reaction temperature and time to reach the different distribution of particle size. By using the method of coprecipitation preparation to have the varity of CQDs/Bi OCl composite materials, through comparision, the material of CQDs/BiOCl(50-150 nm) exhibited the better efficiency, for this moment,the optimized BiOCl/CQDs(50-150 nm) composites showed large speci?c surfacearea, the best improvement of light absorption, the most effective separation and fast transfer of the photogenerated charge carriers, leading to the highest visible-light photocatalytic performance for the degradation of pollutants. At the same time, we also studied on the mechanism of the photoactivity, reaching the main and minor factors on the catalysis of 2NP are that: direct oxidation of hole and oxidation of hydroxyl radical.(2) Preparation and research of black BiOCl/rGO photocatalysts. BiOCl was prepared by Room Temperature Method in the presence of bismuth nitrate pentahydrate and potassium chloride. Then using the simple and one step method of coprecipitation to syntheze different amount of GO dopped with BiOCl; finally, the composite materials of black BiOCl/rGO were reached through a mild and green reduction of iron powder. By compared experiments, we got the excellent photoactivity efficiency with the doped GO of 400 mg, that is because in this moment,the black Bi OCl/rGO0.4 composites showed the best improvement of light absorption and visible light response, the most effective separation and fast transfer of the photogenerated charge carriers. At the same time, we also studied on the mechanism of the photoactivity of black BiOCl, BiOCl/GO0.4 and black Bi OCl/rGO0.4 materials,reaching the main and minor factors on the photocatalysis of 2NP are that: direct oxidation of hole and oxidation of hydroxyl radical.