The Modification Of WO₃ And The Preparation And Photocatalytic Performance Of One-piece Composite Materials

With the development of human social science and technology,environmental pollution and energy crisis are increasingly endangering people’s physical and mental health.Photocatalytic technology has been employed for many fileds.Tungsten trioxide(WO3)semiconductor photocatalyst has become a hot spot in the research of photocatalytic materials due to its low price,easy preparation,strong oxidation performance and selectivity.Tungsten trioxide doped with alkali metal ions has been prepared via hydrothermal method,and the effect of alkali metal ions on the photocatalytic activity of WO3 in the full spectrum also been studied.The experimental results demonstrated that the precursors with ammonium bitungstate(AMT),alkali metal ions exist in the channels of the hexagonal WO3(h-WO3).They played a key role on stability and photocatalytic activity of the h-WO3.The ionic radius is too large to maintain the stability of structure and reduce photocatalytic activity.By X-ray diffraction(XRD)and UV-DRS analysis,Li+ and Na+ did not destroy the h-W03 channel as well as the structure stability because of the smaller radius.And to a certain extent,they improve the absorption performance.By fluorescence spectroscopy(PL),we found that the alkali metal ions have acted an important role as electronic receptors and capture trap in the process of photocatalytic reaction,reduced the electronic-hole composition and improved the photocatalytic activity of the materials.WO3/GO photocatalytic materials mechanical successfully be prepared by stirring and freeze-drying method without adding any additives or template agents.The experimental results of photocatalytic oxidation of nitric oxide(NO)showed that NO removal rate of WO3/GO was increased by 3.3 times which compared with pure WO3.There are three reasons for the improvement of WO3 photocatalytic performance.First,the introduction of GO enlarged the specific surface area of WO3 which promoted the adsorption performance of pollutants as well as the utilization efficiency of the catalyst,and the larger specific surface area exposed more active sites for photocatalytic reaction.Second,ultraviolet absorption spectra(UV-DRS)showed that GO can narrow the gap and improve the absorptivity.Last,fluorescence spectroscopy(PL)shows that the the high conductivity of GO make it as an electron acceptor to promote electron transfer and reduce the photoproduction electronic-hole composition.WO3/GO is easy to recycle,with less toxic by-products,its highest NO2 generated rate is less than 1.8%.thus we truly realize the"purification" of pollutants.WO3/GO with different matrix materials were prepared by immersion and freeze-drying method.We discussed the effects of different matrix materials on photocatalytic activity and studied the properties of methane water vapor reforming.The experimental results showed that the inert matrixs enhance the material mechanical strength with photocatalytic activity decreasing.The study of photocatalytic methane water vapor reforming performance shows that the CO and CO2 from the decomposition of GO.