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Chemisorption of CO, NO, and H/sub 2/ on transition metal-titania thin film model catalysts

Journal Article · · J. Catal.; (United States)
OSTI ID:5648238
Chemisorption on thin film models of Rh/TiO/sub 2/ and Pt/TiO/sub 2/ catalysts before and after encapsulation with TiO/sub x/ (1.0 less than or equal to x less than or equal to 1.2) is reported. TiO/sub x/ blocks adsorption sites and induces new desorption states. A CO desorption peak, assigned to CO on Rh atoms perturbed by TiO/sub x/, is observed at 325 K after adsorption at 120 K on a TiO/sub x/-covered Rh/TiO/sub 2/ surface. CO adsorbed at 285 K onto the encapsulated Rh/TiO/sub 2/ surfaces shows a new 685 K CO desorption state attributed to an activated form of CO with a weakened C-O bond. NO desorbs from clean Rh overlayers with a profile most like Rh(110). On encapsulated Rh surfaces N/sub 2/O is the major desorption product. Compared to bulk Pt, desorption experiments show suppressed H/sub 2/ adsorption capacity for thin (< 2 ML) Pt layers in contact with, but not encapsulated by, TiO/sub x/. For thin layers of Pt on fully oxidized TiO/sub 2/ layers there is no reduction of H/sub 2/ chemisorption. The results suggest bonding between Ti and Pt which affects H/sub 2/ chemisorption even though no Pt surface sites are blocked.
Research Organization:
Univ. of Texas, Austin
OSTI ID:
5648238
Journal Information:
J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 102:2; ISSN JCTLA
Country of Publication:
United States
Language:
English