SO/sub 2/ deactivation in NO reduction by NH/sub 3/. IV. Auger studies of deactivated catalysts in selective NO reduction

Journal Article · Tue Jan 01 04:00:00 EST 1980 · J. Catal.; (United States)

OSTI ID:5440252

Tsai, J; Agrawal, P K; Sullivan, D R; Katzer, J R; Manogue, W H

Deactivation of supported metal catalysts by SO/sub 2/ in the selective reduction of NO by NH/sub 3/ was studied in a differential, packed-bed flow reactor as a function of the gas-phase O/sub 2/ concentration, and foils of the same metal as the catalyst were placed in the reactor with the catalyst. Auger electron spectroscopy (AES) was used to analyze the metal foils subsequent to reaction. With no SO/sub 2/ in the feed gas, the rate of NO reduction over Pt/Al/sub 2/O/sub 3/, Ru/Al/sub 2/O/sub 3/, and Ni/Al/sub 2/O/sub 3/ was enhanced by the presence of 0.5 mole% O/sub 2/, whereas that for Pd/Al/sub 2/O/sub 3/ was reduced. AES studies confirm that the deactivation of Pd in the sulfur-free system is due to oxidation of the metal. Although SO/sub 2/ severely poisons the catalytic activity in the NO-NH/sub 3/-SO/sub 2/ system, addition of 0.5 mole% O/sub 2/ to the feed gas largely restores the activity of all catalysts. This elimination of severe SO/sub 2/ deactivation correlates well with the incorporation of oxygen to high conentrations into the subsurface layers of the metal: oxygen appears to counteract the presence of sulfur incorporation. Only metal oxides and metal sulfides were formed; there was no evidence of sulfate formation. 18 references, 11 figures, 2 tables.

• Research Organization: Univ. of Delaware, Newark
• OSTI ID: 5440252
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 61:1; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AMMONIA
AMMONIUM COMPOUNDS
AUGER ELECTRON SPECTROSCOPY
CATALYST SUPPORTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CHROMATOGRAPHY
CRYOGENIC FLUIDS
DATA
DATA FORMS
DEACTIVATION
ELECTRON SPECTROSCOPY
ELEMENTS
EXPERIMENTAL DATA
FLUIDS
FOILS
GAS CHROMATOGRAPHY
HELIUM
HIGH TEMPERATURE
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
ISOLATED VALUES
MECHANICAL STRUCTURES
METALS
NICKEL
NITRIC OXIDE
NITRITES
NITROGEN
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NITROGEN OXIDES
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PALLADIUM
PLATINUM
PLATINUM METALS
RARE GASES
REDUCTION
REFRACTORY METALS
RUTHENIUM
SEPARATION PROCESSES
SPECTROSCOPY
STEADY-STATE CONDITIONS
SUPPORTS
TEMPERATURE DEPENDENCE
TRANSITION ELEMENTS
YIELDS