Interaction and reactivity of nitric oxide and carbon monoxide on ruthenium surfaces

Technical Report · Sat Mar 01 04:00:00 EST 1980

DOI:https://doi.org/10.2172/5581549· OSTI ID:5581549

Quick, E. E.

A multifaceted investigation of the reduction of nitric oxide by carbon monoxide using a ruthenium (102) single crystal catalyst in the pressure range 10/sup -3/ to 10 Torr and temperature range of 300 to 475/sup 0/C has been undertaken. Kinetic and isotopic results indicate that the reaction products CO/sub 2/ and N/sub 2/ were produced via two reaction mechanisms. Using a reducing gas mixture (low P/sub NO//P/sub CO/ ratio) a two site mechanism was operative involving NO dissociation. The carbon monoxide kinetic order varied from +1 to -3 and the nitric oxide order varied from +1 to 0. The catalyst under these conditions was determined to be metallic ruthenium with oxygen bonded within the first surface layer. The oxygen was unreactive and formed a (1 x 3)-0 LEED pattern. Under oxidizing conditions (high P/sub NO//P/sub CO/ ratio) the catalyst was ruthenium dioxide and the functional mechanism under these reaction conditions yielded a nitric oxide order of +2 to -4. Inclusion of a site poisoning mechanism under reducing conditions and an RuO/sub 2/ growth mechanism involving ruthenium cation transfer under oxidizing conditions into the kinetic rate laws led to an overall rate law which could be fit to the carbon monoxide and nitric oxide order plots. Using isotopically oxygen labelled reactants, it was observed that the three possible isotopes of carbon dioxide were produced. A ..gamma..-CO surface species is postulated as an intermediate in the exchange process. The reaction was observed to be initially surface structure insensitive and the reaction kinetics were derived using a Langmuir-Hinshelwood formalism.

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5581549
• Report Number(s): IS-T-885
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330701 -- Emission Control-- Nitrogen Oxides
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
ELEMENTS
KINETICS
METALS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
REACTION KINETICS
REDUCTION
REFRACTORY METALS
RUTHENIUM
RUTHENIUM COMPOUNDS
RUTHENIUM OXIDES
SURFACES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS