•Cs0.32WO3/SiO2 aerogel multilayer composite coating was prepared on glass substrate.•The effect of SiO2 aerogel coating thickness on the light transmittance was studied.•The composite coating exhibited excellent heat shielding and insulation properties.A novel Cs0.32WO3/SiO2 aerogel multilayer composite coating has been fabricated on glass substrate using the colloidal dispersion of Cs0.32WO3 and SiO2 aerogel nanoparticles, respectively. The effects of SiO2 aerogel layer thickness on the visible and near-infrared light transmittance of Cs0.32WO3/SiO2 composite coating have been investigated. The results indicate that the composite coating can achieve maximum visible light transmission when the thickness of SiO2 aerogels layer is 138 µm. When the aerogel layer thickness exceeds 138 µm, the light transmittance has a decreasing trend and near infrared shielding rate tends to increase further. It is expected that the Cs0.32WO3/SiO2 aerogel multilayer composite coatings with appropriate aerogel layer thickness would not only have higher visible light transmittance, but also have excellent near-infrared shielding and thermal insulation performance.

Cesium tungsten bronze (CsxWO3) powders were synthesized by hydrothermal reaction at 190 °C by using sodium tungstate and cesium carbonate as raw materials, and the effects of N2 annealing on the microstructure and near-infrared (NIR) shielding as well as heat insulation properties of CsxWO3 were investigated. The results indicated that the synthesized CsxWO3 powders exhibited hexagonal Cs0.32WO3 crystal structure, and subsequent N2 annealing could further improve the crystallinity of CsxWO3 particles. Moreover, the NIR shielding and heat insulation properties of CsxWO3 could be further improved after N2 annealing at appropriate temperature for a period of time. Particularly, the 500 °C-annealed CsxWO3 products in the N2 atmosphere showed the best NIR shielding and heat insulation properties. When the N2 annealing temperature was higher than 700 °C, the NIR shielding properties decreased again. The 800 °C-annealed samples in the N2 atmosphere showed higher visible light transmittance, however, the NIR shielding properties were lower than that of the non-annealed samples.

Silica–titania composite aerogels were synthesized via ambient pressure drying by using water glass and titanium tetrachloride as raw materials. The influences of heat-treatment at different temperature with different heating rate on the microstructure and properties of the composite aerogels were investigated by differential thermal analyzer, Fourier transform infrared spectrometer, X-ray diffraction, nitrogen adsorption–desorption, scanning electron microscope and transmission electron microscope analysis. The results indicate that the silica–titania composite aerogels heat-treated at 250 °C exhibited highest specific surface area, pore volume and average pore diameter. When the heat-treatment temperature was higher than 450 °C, the –CH3 groups on the surface of silica–titania composite aerogels would transform into –OH groups gradually, and in the meantime, the composite aerogels network structure would be destroyed gradually and the crystallinity of TiO2 would be improved with the increase of heat-treatment temperature. Particularly, heat-treatment at temperatures above 750 °C would cause serious damage to the network structure of the composite aerogels. The adsorption/photocatalytic activity experiments showed that the composite aerogels heat-treated at 550 °C exhibit highest darkroom adsorption efficiency, and the 650 °C-heat-treated samples exhibited highest efficiency for removing the Rhodamine B from water.

TiO2–SiO2 composite aerogels were prepared via ambient pressure drying by sol–gel and surface modification for both the sol and gel samples. The organosilane reagents of decamethyltetrasiloxane (DMTSO)/trimethylchlorosilane (TMCS) and hexamethyldisiloxane (HMDSO)/TMCS were introduced into the TiO2–SiO2 composite sol for pre-modification respectively, and subsequently the TMCS/hexane solution was used for surface modification of the obtained TiO2–SiO2 composite gel. The effects of sol pre-modification on the microstructure and pore characteristics of TiO2–SiO2 composite aerogels were investigated. The results indicate that HMDSO/TMCS coupling reagents is more appropriate for the pre-modification of TiO2–SiO2 composite sol than the DMTSO/TMCS reagents. The best volume ratio of HMDSO/TMCS/composite sol for preparing mesoporous TiO2–SiO2 composite aerogels is in the range of 1:0.33:10–1:1.0:10, with which the specific surface area and pore volume of the obtained TiO2–SiO2 composite aerogels are 492–645 m2/g and 2.63–2.85 m3/g, respectively. The results of adsorption and photocatalytic degradation of rhodamine B show that the as-prepared TiO2–SiO2 composite aerogels have higher adsorption/photocatalysis. Particularly, the as-prepared TiO2–SiO2 composite aerogels with HMDSO/TMCS showed prominent adsorption capability with the adsorption rate attaining to 89.4 % within 60 min.