Deviation from stoichiometry is a general property of oxides, and the defect structures results in semiconducting properties. Anion vacancies are reported as the usual stoichiometric point defects (references 19, 21, and 22).
Conduction at low temperature is dominated by proton movement by vehicle mechanism, facilitated by molecules of physically adsorbed H2O having high mobility.
Weak adsorption of water on g-alumina produces an increase in the apparent capacity/relative dielectric constant.
Mobile species (proton vehicles) exist on alumina surface at low temperature.
The g-alumina support dictates the surface behavior of SnO2.
ZnCr2O4-K2CrO4 exhibits ion hopping and diffusion processes.
By supporting an n-type oxide (SnO2) on an n-type semiconductor support (TiO2), the O2 adsorption and surface oxidation are facilitated by the synergy between the two phases.
Hydrogen-bonded water appears to be the most plausible charge-carrier vehicle for g-alumina at low temperatures, possibly serving as a scaffold to support mobile protons.
By comparing best-fit values of the energetic and entropic parameters in the model to those obtained from quantum-chemical electronic structure calculations, one can dramatically reduce the number of candidates for surface charge carriers and their modes of interaction with the surface.
Sn-Ce-O powders showed catalytic activity for CO oxidation to CO2 at lower temperature (~160 C) due to the synergic effect of the two oxides on the CO oxidation reaction.
The activity of SnO2 for propylene oxidation is strongly diminished when it is supported on g-alumina.
Hydrogen species produced by adsorption on Pt and transferred to the support by hydrogen spillover must be protonic in nature since this process is accompanied by thermal and conductivity effects.