Dispersion and electronic structure of TiO[sub 2]-supported cobalt and cobalt oxide

Journal Article · Sat Jan 01 00:00:00 EST 1994 · Langmuir; (United States)

DOI:https://doi.org/10.1021/la00013a027· OSTI ID:5165017

Shao, Y; Chen, W; Paul, J ^[1]; Wold, E ^[2]

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1. KTH/Royal Inst. of Technology, Stockholm (Sweden)
2. NTH/Norwegian Univ. of Technology, Trondheim (Norway)

Results from a surface study of titania-supported cobalt are presented. The data show a clear interaction between the Ti(110) support and the overlayer, as a function of thermal treatments and oxidation state. Two model substrates, fully oxidized and partially reduced TiO[sub 2], were impregnated with metallic cobalt or cobalt oxide via dry chemical methods. The resulting four combinations, TiO[sub 2]-o/Co, TiO[sub 2]-o/CoO, TiO[sub 2]-r/Co, and TiO[sub 2]-r/CoO, were compared with reference spectra for the isolated constituents by means of electron spectroscopic measurements following annealing to subsequently higher temperatures. We employ a new fingerprint' technique to analyze the data, thereby allowing us to utilize all available peak positions for a better understanding of chemical interactions and dispersion changes. From our data we can conclude that only metallic cobalt influences the chemical state of titania. The dispersion of CoO changes at moderate temperatures, 500-700 K, but this is restricted to coalescence of the overlayer. The overlayer oxide is less stable on the partially reduced support than on fully oxidized titania. Metallic cobalt, as deposited or from decomposition of CoO, diffuses into titania at above 700 K on TiO[sub 2]-o and above 500 K on TiO[sub 2]-r. This interdiffusion is accompanied by a reduction of the support. The lower stability of CoO on the partially reduced support is accompanied by a stabilization of cobalt in the surface region. 52 refs., 10 figs., 1 tab.

• OSTI ID: 5165017
• Journal Information: Langmuir; (United States), Vol. 10:1; ISSN 0743-7463
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COBALT
DISPERSIONS
ELECTRONIC STRUCTURE
COBALT OXIDES
ANNEALING
CATALYST SUPPORTS
CATALYSTS
ELECTRON SPECTROSCOPY
FISCHER-TROPSCH SYNTHESIS
TITANIUM OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
COBALT COMPOUNDS
ELEMENTS
HEAT TREATMENTS
METALS
OXIDES
OXYGEN COMPOUNDS
SPECTROSCOPY
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
100200* - Synthetic Fuels- Production- (1990-)
400102 - Chemical & Spectral Procedures
400201 - Chemical & Physicochemical Properties