Composite And Properties Of Tungsten Trioxide With Rich Oxygen Vacancies With Carbon Dots

WO₃is an N-type semiconductor material,with a wide band gap,it only has the ability to absorb ultraviolet light,but almost nearly has absorption to visible light and near-infrared light,which make up for about 97%of the solar spectrum.Therefore,as to improve its near-infrared spectral response,WO₃ was reduced to oxygen vacancy in a way in this paper.The prepared WO_3-x has strong near-infrared absorption because of the local surface plasmonic resonance（LSPR）effect caused by oxygen vacancy.Carbon dots compound with WO_3-x to form ultra-small heterostructures,so as to extend the light response range of the material to the full solar spectrum.The number of photogenerated carriers are increased,on the one hand,the heterostructures of CDs@WO_3-x can improve the electronic-hole’s ability on the separation of transfer,thus greatly improve the photocatalytic performance;On the other hand,by adjusting the content of CDs,it can achieve the purpose of utilizing its photothermal properties.The research of this paper mainly involves two aspects:（1）Using the one step of hydrothermal method to synthesis WO_3-x and CDs@WO_3-xbinary composite materials,CDs was successfully compounded on the surface of WO_3-xnanoparticles.The solid absorption test found that the composite material is a material with full spectrum solar energy absorption characteristics.Using OPD as the catalytic substrate,through enzyme kinetics test,it can be seen that the V_max of CDs@WO_3-x is 1.6 times of WO_3-xnanomaterial（under visible light）,and this ratio is even greater under monochromatic light irradiation of about 500 nm,which is about 3.2 times.This result is consistent with solid absorption.It was found that the heterojunction formed by CDs and WO_3-x is good to the transmission of photogenerated electron hole pairs through active substance capture,electrochemical test,MS and XPS valence band position test,and the oxygen vacancies in tungsten trioxide contributes to the intermediate energy level,which opens a new path for photocatalysis.It plays an important role in the improvement of catalytic ability.（2）Acetate fiber cigarette butts have good water transmission channels,low cost and wide sources were selected as the carrier,and the prepared photothermal load was placed on its surface to evaporate water and organic solvents（OPD）in the previous experiment was followed).In this way,the acetate fiber cigarette butts act as the insulation layer and combine the water transmission channel with the insulation device to form a bilayer structure,thus can improve the photothermal conversion efficiency and regulating the energy structure of the photothermal.Under the full solar spectrum irradiation,the water evaporation efficiency of CDs@WO_3-xand WO_3-xwere 1.33 and 1.80 kg m^-2h^-1,respectively.By measuring the evaporation efficiency under different light sources and comparing it with solid absorption,the relationship between the level of light absorption and the evaporation efficiency of water was explored.Through the experiment of evaporating organic solvents,it can be seen that,only water molecules out,and then,water molecules through the glass beaker condensing into water droplets,which is easy to be collected,and then achieve the goal of sewage treatment.