Abstract
Water desorption from highly disperse silica, titania, silica/titania, and silica/alumina surfaces via unimolecular and bimolecular processes was studied by one-pass temperature-programmed desorption (OPTPD) time-of-flight mass spectrometry (TOFMS), differential thermogravimetry, and quantum chemical ab initio and semiempirical AMI and NDDO methods. The use of OPTPD-TOFMS allowed us to obtain quantitative data from different TPD peaks about the amount of water desorbed per nm 2 of the oxide surface. In the case of mixed oxides, the amount of water adsorbed as intact molecules and dissociatively is greater than that on the corresponding individual oxides. The lowest activation energy (about 100 kJ/mol) of associative desorption of water corresponds to the reaction SiO(H)Al(OH) → SiOAl + H 2O. The TPD maxima of water desorbed after heating and rehydration of samples are smaller and lie at lower temperatures than that for starting samples.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Mass Spectrometry and Ion Processes
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
