水热法制备高反射率TiO2壳层中空玻璃微球

以钛酸四丁酯、盐酸、去离子水、中空玻璃微球(HGM)为原料，乙醇为溶剂，采用水热合成法制备了高反射率的锐钛矿型TiO₂壳层HGM(HGM@TiO₂)。采用SEM、EDS、FTIR、XRD、UV-VIS-NIR、导热系数仪研究了钛酸四丁酯用量对微球的表面形貌、表面化学成分、物相结构、反射性能、导热系数的影响。结果表明:锐钛矿型TiO₂成功包覆于HGM表面，包覆形貌完整且均匀，并且包覆层厚度随着钛源用量的增加而变厚；与原始HGM相比，HGM@TiO₂的导热系数有小幅上升，最大上升幅度仅为0.007 W/(m·K)，证明TiO₂的包覆对HGM的隔热性能的影响不大；包覆后的HGM的光谱反射率在可见光波段和近红外波段的反射率得到大幅提升，最大提升幅度为13%，HGM@TiO₂的最高反射率达到90%以上。 

Preparation of TiO2 shelled hollow glass microspheres with high reflectivity by hydrothermal method

The high-reflectivity anatase TiO₂ shell HGM (HGM@TiO₂) was prepared by hydrothermal synthesis method, using tetrabutyl titanate, hydrochloric acid, deionized water, hollow glass microspheres (HGM) as raw materials and ethanol as solvent. SEM, EDS, FTIR, XRD, UV-VIS-NIR, thermal conductivity meter were used to study the effect of the amount of tetrabutyl titanate on the surface morphology, surface chemical composition, phase structure, reflection performance, and thermal conductivity of the microspheres. The results show that: The anatase TiO₂ is successfully coated on the surface of HGM, the coating morphology is complete and uniform, and the coating thickness becomes thicker with the increase of the amount of titanium source; Compared with the original HGM, the thermal conductivity of HGM@TiO₂ has a slight increase, and the maximum increase is only 0.007 W/(m·K), which proves that the coating of TiO₂ has little effect on the thermal insulation performance of HGM. The spectral reflectance of the coated HGM has been greatly improved in the visible and near-infrared bands, with a maximum increase of 13%, and the highest reflectance of HGM@TiO₂ has reached more than 90%.