Preparation And Photocatalytic Properties Of BiVO₄ And TmFeO₃ Nano Powders Obtained By Carbon Adsorption Coprecipitation Method

At present,the rapid development of economy and society makes environmental pollution and energy crisis become urgent problems to be solved in the new era.Photocatalysis technology is an ideal green technology to solve the above two problems,which has great potential in the degradation of environmental pollutants,solar cells and water splitting to hydrogen,and other fields.The key to realize industrial application of photocatalytic technology is to find a photocatalytic material with high efficiency,stability and wide spectral response.The research on photocatalyst has made great progress,however,there is still a large gap with the large-scale application.At present,the domestic and foreign studies reported that TiO₂ or modified TiO₂ photocatalyst got the main focus.Nevertheless,due to the forbidden band width of TiO₂ itself is wide?³.2 eV?,its light-response range is narrow,and there is very little light in the sun that can stimulate its response,about 4%,the photocatalytic efficiency of TiO₂ under sunlight is very poor..In addition,it also has the disadvantages such as low separation efficiency of photogenerated electron-hole pairs and low quantum efficiency,which greatly limits the practical application of TiO₂ based photocatalysts.Therefore,it is of great scientific research value and practical significance to research and develop new semiconductor photocatalytic materials with high efficiency.This article explored the novel preparation of BiVO₄ nanopowder by carbon adsorption method.The influence factors of semiconductor under visible light were studied systematically.The visible light catalytic reaction mechanism was also discussed.The main contents are summarized as follows:?1?Bismuth nitrate and ammonium vanadate were using as raw material,adding sodium hydroxide as a mineralizer,the bismuth vanadate nanopowder was prepared by carbon adsorption method.UV-vis spectrophotometer?UV-vis?,the differential thermal analyzer and thermal gravimetric?TG-DTG?,X-ray diffraction?XRD?,transmission electron microscopy?TEM?were used to characterize dispersion,granularity,phase and light absorption properties of samples powders under different calcination temperature,respectively.The results showed that the BiVO₄ nanopowder with small and uniform particles and less agglomeration obtained by carbon adsorption method exhibited good dispersion.?2?The TmFeO₃ adsorbed on carbon were prepared by the hydrothermal method.Their specific surface area,thermal stability and physical structure of the crystal were analyzed by TGA,XRD,UV-Vis.The degradation of methyl orange was used as the experimental object of phot catalysis,and dysprosium lamp was used as the visible light source.The experimental results show that TmFeO₃ adsorbed on carbon prepared by the hydrothermal method has better crystallinity,higher thermal stability,larger specific surface area and better absorptivity than that without carbon.The experimental results of photocatalytic degradation of methyl orange showed that the degradation rate of TmFeO₃adsorbed on carbon methyl orange reached 88%after light irradiation for 140 min and was1.4 times of TmFeO₃.?3?The mechanism was studied and combined with thermogravimetry and infrared analysis to adsorption properties,a possible reaction mechanism under visible light was proposed.