Search

Powdered nanocrystalline tin dioxide has been prepared by two different methods: conventional hydrolysis of SnCl4 solution and the so-called criosol technique. The latter involves treatment of a sodium stannate solution by a cation exchange resin in the H+ form and subsequent freeze drying. The microstructure, composition, specific surface area and electrical properties of the samples were investigated. The application of the criosol technique was shown to result in stable nanoscale particles of tin dioxide. The sintered pellets obtained by this method are characterised by significantly higher values of the resistance in comparison to material prepared by the conventional technique.

The effect of changing the doping metal (M=Cu, Ni, Pd, Pt) on the kinetics of oxygen exchange reactions of polycrystalline SnO2 thin films with gaseous oxygen was studied in situ by conductance measurements. It was found that preliminary annealing of SnO2-based materials in inert (N2) and active (100 ppm H2S in N2) atmospheres affects the kinetics of their reaction with oxygen. Two kinetic models describing the interactions of semiconducting porous materials with gases, i.e., diffusion and surface chemical reactions, are considered.