Spectroscopic study of the effects of carrier doping on the surface structure of Rh/TiO[sub 2] catalysts and on their interaction with CO and H[sub 2]

Journal Article · Thu Jul 07 00:00:00 EDT 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100078a024· OSTI ID:7102786

Zhang, Z; Kladi, A; Verykios, X E ^[1]

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1. Univ. of Patras (Greece)

FTIR and laser-Raman spectroscopies are employed to investigate the structure of Rh catalysts supported on W[sup 6+]-doped TiO[sub 2] carriers and their interaction with CO and H[sub 2]. The results of Raman study show that the surface of the TiO[sub 2] carrier (sintered at 1173 K) contains both the rutile and anatase structures, in contrast to the bulk, which is 100% rutile. Doping of TiO[sub 2] with W[sup 6+] cations increases the proportion of the anatase structure on the surface. The concentration of CO adsorbed on the Rh surface (i.e., the sum of the gemdicarbonyl Rh[sup +](CO)[sub 2], linear Rh[sup 0]CO, and bridged Rh[sup 0][sub 2]CO), following exposure to 76 Torr of CO at 300 K, is found to exhibit a maximum with respect to dopant content at a level of 0.11-0.22 at. %. Blue shifts by 9 cm[sup [minus]1] of the linear CO band on the Rh crystallites and by 11 cm[sup [minus]1] of the gem-dicarbonyl band on the isolated Rh[sup +] sites are observed when Rh is supported on the doped carriers. The alterations in the CO adsorption capacity and in the frequency of the C-O bond, upon carrier doping, are attributed to electronic interactions between the Rh crystallites and the doped TiO[sub 2] carrier, which result in alterations in the electronic configuration of the rhodium sites. Preadsorbed hydrogen on the doped catalyst is found to greatly retard the rate of subsequent CO adsorption. 51 refs., 8 figs., 2 tabs.

• OSTI ID: 7102786
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:27; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104 -- Metals & Alloys-- Physical Properties
360606* -- Other Materials-- Physical Properties-- (1992-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201 -- Chemical & Physicochemical Properties
ADSORPTION
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYSTS
CHALCOGENIDES
CHARGED PARTICLES
COMPILED DATA
CRYSTAL DOPING
DATA
ELEMENTS
HYDROGEN
INFORMATION
INFRARED SPECTRA
IONS
LASER SPECTROSCOPY
MATERIALS
METALS
MINERALS
NONMETALS
NUMERICAL DATA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
RADIOACTIVE MATERIALS
RADIOACTIVE MINERALS
RAMAN SPECTROSCOPY
RHODIUM
RUTILE
SORPTION
SPECTRA
SPECTROSCOPY
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TUNGSTEN IONS