Study On Preparation And Performance Of PbBiO₂Br

With the increasing severe of energy and environmental problems, the photocatalytic technique has been one of the currently important researches for its great potential on solving the two problems. The photocatalytic process is a complex surface chemical reaction, which is mainly occurred on the active site of photocatalysts surface with reactant adsorbed. Therefore, the adsorption ability is one of the important properties for a catalyst. In this paper, PbBiC2Br with good photocatalytic degradation activity and adsorption capacity was controlled synthesized by a one step hydrothermal method. The main works and results are summarized as follows:1. The preparation and characterization of catalyst:using a simple one step hydrothermal method, a series of PbBiO2Br were obtained by modulating the reaction conditions such as ratio of raw materials, hydrothermal temperature and duration. The as-synthesized samples were charactierized by means of XRD, SEM, BET, XPS, PL, etc. The calculated band gap of photocatalyst is 1.58 eV based on the UV-vis DRS, which is far lower than that of BiOBr (2.5-2.9 eV). It indicated that the introduction of Pb element lead to the low band gap of PbBiO2Br-1:2. PL results suggest that the photogenerated charge carriers can be separated efficiently on PbBiO2Br. Calcination of the as-prepared PbBiO2Br could resulted to higher cristallinite but lower BET surface area and wider bang gap energy.2. Other kinds of dye degradation and K2Cr2O7 adsorption properties:Degradation of RhB was used as a proble reaction to envaluate the photocatalytic activity of theprepared catalysts. Results showed that PbBiO2Br-1:2 displayed the best activity. The PbBiO2Br-1:2 also showed high acivity towards the degradation of MB, MO and CV under visible light illimunation indicating the universal application of PbBiO2Br-1:2 for organic dye removal. From the treatment of RhB and K2Cr2O7 mixture, it was found that the adsorption of K2Cr2O7 reaches 90% at the same time that 95% of RhB decomposited within 30 min visible light irradiation. The XPS analysis indicated that it was just an adsorption process rather than reduction process of Cr (VI). The adsorption capacity of K2Cr2O7 on PbBiO2Br-1:2 obtained by the flow adsorption tests is 12.4 mg/g and the adsorption stability is also very good.