Carmen Canevali, Norberto Chiodini, Patrizia Di Nola, Franca Morazzoni, Roberto Scotti and Claudia L. Bianchi
Electron paramagnetic resonance (EPR) studies have been carried out on lattice oxygen vacancies produced by the interaction of carbon monoxide with SnO2 obtained by sol–gel type condensation. Under a 0.5% CO–argon reducing atmosphere the vacancies can transfer electrons to Sn4+ producing Sn2+ centres. In air the lattice defects interact with molecular oxygen in a manner which depends on whether the gas reducing treatment was performed under dry or moist conditions. Defects that undergo oxygen interaction at the SnO2 surface, reduce O2 to O2- or O2- , depending on the temperature of the reaction with oxygen.