Effect of antimony on the reaction of nanocrystalline SnO2 with oxygen

Resumo

Nanocrystalline antimony-doped ([Sb]/([Sb] + [Sn]) = 0–2 at %) SnO₂ powders have been synthesized by coprecipitation from solution. The composition, crystal structure, and microstructural parameters of the powders, as well as the antimony distribution in them, have been studied by laser mass spectrometry, X-ray diffraction, low-temperature nitrogen adsorption measurements, and IR spectroscopy. The reaction of the synthesized materials with oxygen has been studied in situ by electrical conductance measurements. Oxygen chemisorption on the surface of unmodified SnO₂ leads to predominant formation of the molecular species O_2(ads)^-. Increasing the Sb concentration in the SnO²‹Sb› samples increases the fraction of the monatomic species O_2(ads)^-, which can be explained in terms of a combination of crystal-chemical and electronic factors.