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%.