CO adsorption-desorption properties of cation-exchanged NaX zeolite and supported ruthenium

Journal Article · Fri Dec 01 00:00:00 EST 1989 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(89)90283-2· OSTI ID:6781424

Gupta, N M; Kamble, V S; Rao, K A; Iyer, R M ^[1]

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1. Bhabha Atomic Research Centre, Bombay (India)

The binding states of carbon monoxide over cation-exchanged NaX zeolites and over corresponding Ru-containing samples have been investigated using thermal desorption spectroscopy. Exchange of sodium with cations such as Li{sup +}, Ca{sup 2+}, Mg{sup 2+}, and La{sup 3+} gave rise to additional CO adsorption states, a higher isosteric heat of CO adsorption, an increased density of acid sites, and an increased amount of adsorbed CO, depending on the nature and ionic radius of the charge-balancing cation. The charge-balancing cations at the zeolite surface (e.g., Ca{sub 2+}, La{sup 3+}) function as additional CO adsorption sites in conjunction with surface acid centers (e.g., the Al{sup 3+} center) and metal sites. In addition to surface sites, CO is also found to be held in structural cavities and macropores of the zeolite matrix. The programmed heating of both the metal-free and Ru-containing zeolites subsequent to room temperature CO adsorption gave desorption peaks due to release of CO at temperatures less than {approximately}500 K while the higher temperature peaks were constituted mainly of CO{sub 2}. Electron spectroscopy results have revealed that the exposure of these samples to CO and subsequent thermal treatment resulted in the formation of surface carbonaceous species. The nature of CO adsorption states giving rise to CO{sub 2} formation is discussed.

• OSTI ID: 6781424
• Journal Information: Journal of Catalysis; (USA), Vol. 120:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
CARBON MONOXIDE
ADSORPTION
DESORPTION
RUTHENIUM
SORPTIVE PROPERTIES
ZEOLITES
ADSORPTION HEAT
CALCIUM
CARBON
CARBON DIOXIDE
DEPOSITION
ELECTRON SPECTROSCOPY
FISCHER-TROPSCH SYNTHESIS
HEAT TREATMENTS
HYDROGENATION
ION EXCHANGE
LANTHANUM
LITHIUM
MAGNESIUM
METHANATION
MICROSTRUCTURE
POROSITY
SODIUM
SURFACE PROPERTIES
TEMPERATURE CONTROL
ALKALI METALS
ALKALINE EARTH METALS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CONTROL
CRYSTAL STRUCTURE
ELEMENTS
ENTHALPY
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
METALS
MINERALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLATINUM METALS
RARE EARTHS
SORPTION
SPECTROSCOPY
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
010408* - Coal
Lignite
& Peat- C1 Processes- (1987-)