An XPS and FTIR study of SO2 adsorption on SnO2 surfaces

The adsorption of SO2 on SnO2 surfaces obtained from hydrolysis of SnCl4 and NH3 was studied by X-ray Photoelectron Spectroscopy. Tin dioxide surfaces were treated with SO2 at temperatures ranging from 300 to 900°C. For this temperature range, XPS shows that SO2 is adsorbed on tin dioxide surfaces to form two sulphured species: SO32− for temperatures ranging from 300 to 500°C and SO42− for temperatures ranging from 300 to 900°C. With regards to these two chemical species, we were able to confirm their formation using a second analytical technique (FTIR). The formation of these species will be discussed in terms of a comparison between the results of the two techniques. The role played by OH groups in these interactions is also discussed in this article.