Synthesis And Photothermal Properties Of Multifunctional Cesium Tungsten Bronze Infrared Shielding Materials

The solar radiation energy reaching the earth's surface is mainly composed of ultraviolet light?<400nm,5%to 3%?,visible light?400nm to 780nm,43%to42%?,and near-infrared light?>780nm,52%to 55%?.In the summer,infrared light passes through the glass layer to raise the temperature of the room,consuming a lot of energy;in winter,this part of the energy can be used.Experimental studies have found that tungsten bronze nanomaterials have excellent near-infrared shielding properties,which can be used for thermal insulation coating of smart windows,selectively through sunlight,reducing energy consumption and carbon dioxide emissions,and partially solving energy crisis.In addition,tungsten bronze is also widely used in photothermal treatment of tumors.Under the illumination of near-infrared exciter,tungsten bronze nanomaterial absorbs near-infrared light,converts light energy into heat energy,kills cancer cells in the body,and reduces the risk of surgery such as chemotherapy.Photocatalytic degradation is a green,non-polluting method.The selective use of solar light by semiconductor photocatalysts can degrade pollutants and reduce environmental pollution.The multifunctional material composited by photocatalyst?TiO₂,ZnO?and infrared shielding material?Cs_xWO₃?is used for glass coating,which not only solves energy waste and environmental pollution,but also realizes efficient use of solar energy.In this paper,Cesium tungsten bronze was prepared by water-controlled release solvothermal method.On the basis of this,the effects of Cr and Mo doping on the optical properties of Cesium tungsten bronze were investigated.To improve the biocompatibility of Cesium tungsten bronze,surface coating was used.tungsten bronze was prepared by the method and template method.In order to realize the full spectrum utilization of solar energy,N-TiO₂/Cs_xWO₃,ZnO/Cs_xWO₃ composites were prepared by hydrothermal method.The paper consists of the following three parts:?1?Cr-Cs_xWO3,Mo-Cs_xWO₃ was prepared by a water controlled release solvothermal method.The effects of temperature,time and molar ratio on the properties of tungsten bronze were investigated by orthogonal experiments.Through experimental research,it is found that the infrared shielding effect of the material is best when the reaction temperature is 220?,the reaction time is24 h,and the molar ratio is 0.015.Films with different thicknesses were prepared.Thethermalinsulationefficiencyof10?m-Cs_xWO₃,20?m-Cr-Cs_xWO₃,10?m-Cr-Cs_xWO₃ films was 71.6%,68.8%and 58.3%,respectively.the thermal insulation efficiency of the 20?m-Mo-Cs_xWO₃,10?m-Mo-Cs_xWO₃,10?m-Cs_xWO₃film was 81.1%,73.3%and 71.6%,respectively.?2?Cesium tungsten bronze was prepared by surface coating method and template method.The effects of these two methods on the photothermal properties and photothermal conversion efficiency of bismuth tungsten bronze were investigated.The study found:the crystal phase which does not change the bismuth tungsten bronze is prepared by the surface coating method,and is a hexagonal Cs_0.32WO₃ structure.The dispersion was irradiated with an exciter for20 minutes,and the photothermal conversion efficiency of the dispersion of PVP-Cs_xWO₃ was calculated to be 23.1%.The crystal phase of Cesium tungsten bronze prepared by the template method is a hexagonal Cs_0.32WO₃structure.The dispersion of CTAB-Cs_xWO₃ was irradiated with an exciter for20 minutes,and the photothermal conversion efficiency of the dispersion was calculated to be 19.9%.?3?In order to realize the full spectrum utilization of solar energy,N-TiO₂/Cs_xWO₃ and ZnO/Cs_xWO₃ composites were prepared by hydrothermal method.The effects of different ratios on the infrared shielding performance and photocatalytic degradation properties of composites were investigated.Compared with N-TiO₂,the absorbance of N-TiO₂/Cs_xWO₃ composites in the range of 200²500nm is significantly improved.With the increase of Cs_xWO₃content,the transmittance of the composite in the near-infrared region is reduced,and the near-infrared shielding performance is enhanced.With the increase of N-TiO₂ content,the photocatalytic activity of the composites was significantly improved,and the degradation rate of 2N-TiO₂/Cs_xWO₃ in 150min was 50%.ZnO/Cs_xWO₃ composites also have high absorbance in the wavelength range of 200²500nm.Under full-spectrum irradiation,the degradation rate of ZnO/2Cs_xWO₃ in 150 min was 60.9%,which was about 1.5times that of pure Cs_xWO₃ and ZnO.When EDTA-2Na,isopropanol and N₂were added as the capture agents of h⁺,·OH,·O^2-,respectively,the active species in the solution were explored.When N₂ was introduced,the photocatalytic activity was significantly inhibited,indicating that·O^2-Photocatalytic degradation plays an important role.Therefore,when the composite material has a suitable ratio,it can exhibit excellent synergistic effects,not only having high visible light transmittance and infrared shielding properties,but also degrading contaminants.