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Infrared studies of CO adsorption on reduced and oxidized Pt/TiO/sub 2/

Journal Article · · J. Catal.; (United States)
OSTI ID:6264465

Carbon monoxide adsorption experiments were studied on reduced and oxidized Pt/TiO/sub 2/ with FT-IR. On reduced samples two kinds of linear CO species were observed and assigned as adsorption on Pt close-packed (terrace) sites (2094 cm/sup -1/) and on Pt open (step) sites (2077 cm/sup -1/). In addition a bridged CO species was found at 1854 cm/sup -1/. Both linear species show increasing frequencies with coverage. Saturation CO uptake decreases with increasing substrate reduction temperature and there is a preferential decrease of linear CO species on terrace sites and the concentration of bridged species lies below detection limits. On oxidized Pt/TiO/sub 2/ samples, some Pt atoms are covered with oxygen atoms and the density of step sites is enhanced. On these surfaces there are two kinds of linear CO species assigned to terraces (2130 cm/sup -1/) and steps (2101 cm/sup -1/) and a bridged CO species at 1880 cm/sup -1/. In addition, several CO species are found which are also detected on reduced samples. These species show intensity variations during lengthy exposures. Preadsorbed linear CO species (2130, 2094, and 2077 cm/sup -1/ bands) on oxidized samples are also sensitive to H/sub 2/ exposures.

Research Organization:
Univ. of Texas, Austin
OSTI ID:
6264465
Journal Information:
J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 79:1; ISSN JCTLA
Country of Publication:
United States
Language:
English