Direct formation of SiO2/SnO2 composite nanoparticles with high surface area and high thermal stability by sol–gel-hydrothermal process

SnO2/SiO2 composite nanoparticles were prepared by sol–gel-hydrothermal process and their physico-chemical structure and photocatalytic property were investigated. The results of XRD, TEM and FT-IR indicated that SnO2 crystallites with the tetragonal rutile structure were well-developed directly during hydrothermal process. The SnO2/SiO2 composite nanoparticles owned narrow size distribution, large specific surface area, and good thermal stability. As the presence of 25.0 wt% SiO2, the SnO2 nanoparticles were about 4.0 nm in diameter and the specific surface area was 259.0 m2/g. After calcination at 800 °C, the crystalline grain size maintained 16.2 nm and the surface area still remained 132.6 m2/g. The SnO2/SiO2 composite nanoparticles showed better photocatalytic activity than pure SnO2 nanoparticles.