Colloidal dispersions of crystalline SnO2 (sols) with a mean grain (crystallite) size controlled between 6 and 16nm were prepared successfully from stannic acid gel by hydrothermal treatments under the condition of pH 10.5 and 200°C or pH 12.2 and 250°C. The growth of crystallites saturated in a few hours of hydrothermal treatment and the saturation values tended to increase with increasing SnO2 gel content, pH and temperature. The SnO2 grains remained monodispersed unless time of hydrothermal treatment was excessive. Thin films of SnO 2 prepared on an alumina substrate from the sols by a spin-coating method responded sharply to H2 gas. The magnitude of sensor response as well as its dependence on operating temperature were different significantly depending on the grain sizes of the starting sols. Among the sols with a mean grain size of 6, 8.5, and 10nm, the last two gave large response to H 2, which reached a maximum at 400 or 350°C, respectively.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering
- Materials Chemistry