Nitrogen desorption in the reaction of nitric oxide on carbon-supported platinum catalysts

Journal Article · Tue Jul 01 00:00:00 EDT 1986 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(86)90081-3· OSTI ID:5514905

Lim, K J; Loeffler, D G; Boudart, M

The catalytic decomposition of nitric oxide on carbon- and ..gamma..-alumina-supported platinum was studied in a quartz flow reactor between 423 and 623 K. The measured turnover frequency, defined as the number of nitric oxide molecules reacting per surface platinum atom per second, was an order of magnitude higher on the carbon-supported catalysts than on the alumina-supported catalyst or than that projected from earlier work on platinum foil. The rate-determining step for nitric oxide decomposition on Pt/Al/sub 2/O/sub 3/ or Pt foil appears to be the chemisorption of NO on platinum, with inhibition by oxygen, the most abundant reaction intermediate (mari) in equilibrated chemisorption on the same sites as those required for NO chemisorption. By contrast, it appears that on surrounding carbon support, producing CO and CO/sub 2/. The kinetic data suggest that the mari now consists of adsorbed nitrogen atoms. The second-order rate constant k for the associative desorption of nitrogen from platinum obtained for the work is compared with that extracted from published data on NH/sub 3/ decomposition or that measured directly by temperature-programmed desorption of nitrogen from platinum. It is found that for k a preexponential factor of 5 x 10/sup -9/ cm/sup 2/s/sup -1/ and an activation energy of 88 kJ mol/sup -1/, in remarkable agreement with those reported by others.

• Research Organization: Stanford Univ., CA
• OSTI ID: 5514905
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 100:1; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBON
CATALYSIS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMICAL REACTORS
CHEMISORPTION
DATA
DECOMPOSITION
DESORPTION
ELEMENTS
EXPERIMENTAL DATA
HIGH TEMPERATURE
INFORMATION
KINETICS
METALS
NITRIC OXIDE
NITROGEN
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PLATINUM
PLATINUM METALS
REACTION INTERMEDIATES
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
TRANSITION ELEMENTS