Preparation And Photocatalytic Properties Of Bismuth Oxychloride Composite

In recent years,with the rapid development of industry and agriculture,water pollution as the main part of environmental pollution has attracted widespread attention.Organic pollutants,heavy metal ions and residual antibiotic drugs in the water body will cause great damage to organisms,so the degradation and elimination of the above pollutants is an urgent environmental problem to be solved.As an important part of advanced green catalytic oxidation technology,semiconductor photocatalysis technology has become the most potential key method to reduce environmental pollution.Among them,photocatalyst is the core of the whole reaction system.The construction of heterogeneous photocatalytic system can solve the problems of low solar energy utilization and short photo-carrier life to a certain extent.This paper takes the semiconductor BiOCl with unique layered structure as the main research object.Substrate catalysts with different morphologies were prepared by hydrothermal and solvothermal methods,and a heterostructure catalyst system was constructed by semiconductor composite method.To explore the effects of catalysts on photocatalytic degradation/reduction of organic pollutants,heavy metal ions Cr（Ⅵ）,and ciprofloxacin CIP activity and degradation mechanism.The results obtained through analysis provide a reference for further solving the problem of water pollution and constructing a new efficient catalyst system.The main research contents are as follows:BiOCl samples with different morphologies were prepared by one-step hydrothermal method using bismuth nitrate,sodium chloride and ethylene glycol as raw materials,and determined and analyzed by XRD,SEM,DRS and other basic tests.By controlling the same experimental conditions to test the photocatalytic properties of the sample,S2 sample,namely 3D graded flower-like BiOCl,showed higher comprehensive performance,and showed the highest degradation efficiency for the degradation of three simulated pollutants under visible light.BiOCl/CdS composite photocatalyst with visible light absorption was prepared with BiOCl as the carrier,and was used for the photocatalytic property test.The composite sample F2 has the best activity through comprehensive evaluation:Under the condition of visible light irradiation,the degradation rate of compound sample F2 for organic dye Rhodamine B is about 99.21%within 30 minutes;in the photocatalytic reduction Cr（Ⅵ）test,about 91.54%of the pollutants are removed by sample F2 when the illumination duration is 60 minutes,and the reduction rate is about 4.58 times of the sample S2 under the same conditions;In the degradation experiment of CIP,approximately 92.65%of the pollutants can be removed by sample F2 after 60 minutes of illumination.Through the free radical capture test,it is concluded that photogenerated electrons play a key role in the degradation system.The S2 sample with better comprehensive performance was systematically investigated and summarized as the carrier.It was compounded with Bi₂S₃,a narrow-band gap semiconductor.By adjusting the concentration of sulfur source and applying the resultant composite sample to the photocatalytic property test,the optimal load was explored through data comparison.The sample A2 with the best activity can degrade about 92.78%MO under continuous visible light irradiation,and the degradation rate is about 6.07 times of S2;the reduction rate of Cr（Ⅵ）can reach 73.37%within 60 min;CIP can be degraded almost completely under visible light for 60 minutes.