Surface structure and mechanisms of gasification catalysts deactivation. Quarterly report, August 1--October 31, 1977

Technical Report · Tue Feb 01 04:00:00 EST 1977

DOI:https://doi.org/10.2172/6778309· OSTI ID:6778309

Reucroft, P. J.; Bradley, E. B.; De Angelis, R. J.; Sargent, G. A.

The vacuum and gas adsorption system which will be used to study adsorbed species via laser Raman spectroscopy is described. Preliminary Raman data from the Ni(111) plane show a forbidden mode which will be studied further in order to determine its origin. Raman and infrared spectra of a NiO/Cr/sub 2/O/sub 3//MgSiO/sub 3/ catalyst are presented and interpreted in terms of Si--O--Cr complexes with SiO/sub 4//sup 2 -/ and CrO/sub 4//sup 2 -/ coordination before methanation tests. After being exposed to typical methanation conditions, the spectra are closer to those expected for mixtures of NiO + Cr/sub 2/O/sub 3/ + MgSiO/sub 3/. Far-infrared studies on SiO/sub 2/-, Al/sub 2/O/sub 3/-, and MgSiO/sub 3/-supported catalysts are summarized. The interaction of CO with a sulfur-contaminated Ni(111) surface was studied by the Auger Technique at three different temperatures: -48/sup 0/C; 30/sup 0/C, and 100/sup 0/C. Results have shown differences in the binding states at different temperatures. It has also shown that the presence of sulfur blocks the adsorption of CO. NiSiO/sub 3/ and NiAl/sub 2/O/sub 4/ samples displayed ESCA spectra like those of the unreduced Ni/SiO/sub 2/ and Ni/Al/sub 2/O/sub 3/ catalysts, but NiAl/sub 2/O/sub 4/ was reduced by argon ion etching, contrary to expectations. The etching procedure was evaluated and it was found that the form of the sample (pellet versus powder) influenced the degree of reduction observed for NiO. MgSiO/sub 3/ supported catalysts appeared to show little interaction with the support. Sulfiding a reduced version of these catalysts leads to deactivation due to the formation of NiS deep in the sample. X-ray diffraction studies to determine the particle size distribution in reduced and passivated catalysts have been continued. A good correlation has been found between the crystallite sizes determined from hydrogen chemisorption surface area measurements and x-ray line broadening analyses.

• Research Organization: Kentucky Univ., Lexington (USA)
• OSTI ID: 6778309
• Report Number(s): FE-2229-7
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AUGER ELECTRON SPECTROSCOPY
BINDING ENERGY
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHROMIUM COMPOUNDS
CHROMIUM OXIDES
COAL GASIFICATION
COHERENT SCATTERING
DEACTIVATION
DIFFRACTION
ELECTRON DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY
GASIFICATION
INFRARED SPECTRA
MAGNESIUM COMPOUNDS
MAGNESIUM SILICATES
METALS
NICKEL
NICKEL COMPOUNDS
NICKEL OXIDES
OXIDES
OXYGEN COMPOUNDS
PASSIVATION
RAMAN SPECTRA
REDUCTION
SCATTERING
SILICATES
SILICON COMPOUNDS
SILICON OXIDES
SPECTRA
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
X-RAY DIFFRACTION