Preparation of TiO2 shelled hollow glass microspheres with high reflectivity by hydrothermal method
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摘要: 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。Abstract: 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%.
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Key words:
- hollow glass microsphere /
- hydrothermal synthesis method /
- TiO2 coating /
- anatase type /
- reflectivity
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表 1 中空玻璃微球(HGM)的基础参数
Table 1. Basic parameters of hollow glass microsphere (HGM)
Paremeter Median particle size/μm True density/(g·cm−3) Compressive strength/psi Wall thickness/μm Value 55 0.2 500 0.69 表 2 TiO2壳层HGM(HGM@TiO2)的配方
Table 2. Formula of TiO2 shell HGM (HGM@TiO2)
Sample KH550-HGM/g Tetrabutyl titanate/g Mass ratio/% HGM@TiO2-1 0.25 0.125 50 HGM@TiO2-2 0.25 0.25 100 HGM@TiO2-3 0.25 0.375 150 HGM@TiO2-4 0.25 0.5 200 HGM@TiO2-5 0.25 0.625 250 HGM@TiO2-6 0.25 0.75 300 表 3 包覆层厚度与钛酸四丁酯用量的关系
Table 3. Relationship between the thickness of the coating layer and the amount of tetrabutyl titanate
Sample TiO2 coating thickness/nm HGM@TiO2-1 — HGM@TiO2-2 83 HGM@TiO2-3 194 HGM@TiO2-4 210 HGM@TiO2-5 223 HGM@TiO2-6 238 -
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