Preparation Of All-solid-state Tungsten Trioxide Photoelectrode And Its Application In Detoxification Of Water Pollutants

With the development of the times and the development of the industry derived from scientific and technological progress,the pollution of water environment and the shortage of energy are becoming more and more serious,which has become one of the important factors hindering the healthy and sustainable development of human civilization.In order to solve the above environmental problems,various pollution treatment techniques and methods have been developed.Among them,photocatalysis technology has the advantages of environmental protection,economy and scale,and is a very promising technical means in the field of environmental treatment.Semiconductor materials have always had an authoritative position in pollutant purification.The combination of the two is a very effective strategy to repair the environment and protect limited resources.titanium dioxide,as a typical semiconductor material,can not make full use of the solar light in the visible region due to its band gap factors.Recently,tungsten trioxide has attracted much attention as another typical semiconductor due to its excellent physicochemical and thermal stability properties.But tungsten trioxide also has its limitations,the high recombination rate of photogenerated electron-hole pairs inside tungsten trioxide materials,which leads to its limited photocatalytic application.In order to solve this problem,this paper puts forward the following two solutions ideas.（1）constructing an all-solid-state tungsten trioxide nanosheet photoelectrode without secondary contamination and introducing an external bias-cooperative electrocatalytic excitation electron;（2）Loading the heterojunction material on the surface of tungsten trioxide to promote the separation of electrons from holes,and extending the catalytic performance of the material with high magnification by photoelectrochemical synergistic catalysis.In this study,three-dimensional copper mesh was used as substrate to grow flower-like tungsten trioxide nano-flowers on tungsten network by anodizing first and calcining later.Its basic unit was tungsten trioxide nanosheet,which was applied to the catalytic detoxification degradation of organic contaminated antibiotic florfenicol;On the basis of the above work,molybdenum selenide was loaded on tungsten trioxide nanoparticles by hydrothermal method to construct heterojunction and photocatalytic reduction and degradation of heavy metal hexavalent chromium.（1）Using commercially purchased tungsten mesh as the substrate material and Na F/H₂SO₄（98%）as the electrolyte,nano-flowers with tungsten trioxide nanosheets as the basic unit were prepared by one-step anodization;the crystallinity of nano-flowers was improved by adjusting the anodic oxidation voltage.In visible light,coupled with an applied cathode potential（-1.2 V）to achieve 99%photoelectrochemical synergistic catalytic detoxification degradation of antibiotic florfenicol over 120 min.（2）Using sodium molybdate（Na₂MoO₄·2H₂O）as molybdenum source and se powder as selenium source,tungsten trioxide nanosheets prepared by anodic oxidation as substrate,thin-sheet Mo Se₂@WO₃nanosheet heterojunction catalysts were synthesized by hydrothermal synthesis.meanwhile,the best performance catalytic photocathodes were prepared by regulating the dosage of different selenium sources.The results show that the Mo Se₂@WO₃heterojunction catalyst synthesized with appropriate proportion of selenium source and molybdenum source dosage has excellent performance for the reduction of heavy metal Cr（VI）and adsorption in the photoelectrocatalytic system,which indicates that suitable structure matching is beneficial to the efficiency improvement of photocatalysis during the formation of two heterojunctions.