Electrochemical Preparation And Photocatalytic Performance Of Bismuth-based Thin Film

With the rapid development of industrialization as well as urbanization and population,the water environment has encountered serious pollution in the production and daily life of humans.To prevent the scarcity and pollution of water,people has developed a variety of techniques.Photocatalysis is regarded as a promising water treament technology since you can remove organic pollutants,harmful bacterias and some heavy metal ions in the water with the direct utilization of solar energy.However,the conventional photocatalyst can only be excited by UV light,so most of photocatalytic reaction own a low solar energy utilization ratio.Most studies are still focused on the preparation of the namopowder photocatalyst,but the nanopowder photocatalysts possess several defects such as rather difficult to be separated from solution and be recycled,easy aggregation and potential risks for humans.To solve the above-mentioned problem,bismuth-based photocatalyst was chosen to design and optimize the photocatalytical properties.The influence factors of photocatalytic activity of photocatalyst and the mechanism and application of photocatalytic process of degrading organic pollutants and the application of the photocatalysts based on bismuth-based thin film were explored in detail.The main content of this paper is summarized briefly as follows:1.A novel type dendritic Bi/BiOBr thin films has been synthesized by electrochemical method,which is easy and simply.The as-prepared film had been characterized by X ray diffraction(XRD),scanning electron microscopy(SEM),UV-visible spectroscopy(UV-Vis)and so on.The photocatalytic activity of photocatalyst could be affected by the concentration of Bi3+ and the passing electric quantity.The results showed that the best photocatalytic performance film is the sample prepared by 0.04 M Bi3+ and 1.8C passing electric quantity of oxidation,the degradation efficiency of RhB reached 98.9% under visible light irradiation after 90 minutes.The holes and super oxygen anion free radicals played an important role during the process.2.Bismuth thin film has been synthesized by electrochemical method.The as-prepared film had been characterized by X ray diffraction(XRD),scanning electron microscopy(SEM),UV-visible spectroscopy(UV-Vis)and so on.we have demonstratedthat bismuth film are photocatalytically active by introducing for the photocatalysis prosess of 2,4-DCP,given that the conduction and valence bands of semimetallic Bi by the results of characterization and the mechanism of the photocatalysis process.The photocatalytic activity of Bi film could be affected by the concentration of Bi3+ and the added surfactant.The results showed that the best photocatalytic performance film is the sample prepared by 0.03 M Bi3+ and 0.1g PVP,the degradation efficiency of2,4-DCP reached 76.5% under visible light irradiation after 90 minutes.3.Dendritic Bi OCl thin films has been synthesized by electrochemical method,then dendritic Bi OCl/BiOI composite has been synthesized by ion-exchange method with adding KI as I source.The as-prepared film had been characterized by X ray diffraction(XRD),scanning electron microscopy(SEM),UV-visible spectroscopy(UV-Vis)and so on.The degradation efficiency of BiOCl/Bi OI on RhB reached 96.2% under visible light irradiation after 90 minutes,which is obviously higher than the degradation efficiency of Bi OCl or BiOI.The holes,super oxygen anion free radicals and hydroxyl radical all took part in the photocatalysis process,but the holes played the most important role.