Study of the Adsorption of Water on Titania by Secondary Ion Mass Spectrometry

Titania is known to dissociate water photocatalytically [1] but many aspects of the process are not fully understood. Complete agreement does not exist with respect to the character (associative, dissociative) of the water adsorption and the nature of the sites. In this paper, we report preliminary SIMS results concerning the adsorption of water on clean titania powders whose surface stoichiometry is varied and checked by a combination of Auger and SIMS. The main purpose of the present work is then to investigate the potentialities of SIMS as regarding the adsorption of water on oxides. Particularly, we are interested to see if the degree of coverage and the various phases of adsorption can be deduced from static SIMS.