Reduction of nitric oxide with carbon monoxide on the Rh(100) single-crystal surface

Journal Article · Sat Mar 01 00:00:00 EST 1986 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(86)90305-2· OSTI ID:5251044

Hendershot, R E; Hansen, R S

The reduction of nitric oxide with carbon monoxide has been investigated on the Rh(100) single-crystal surface. Steady-state kinetic measurements, at 688 K and in the pressure range 1.0 to 1800 Pa, indicate that this process proceeds via a Langmuir-Hinshelwood-type mechanism and is selective toward the production of N/sub 2/ and CO/sub 2/. The carbon monoxide kinetic order varied continuously from +1 to -1 as the partial pressure of CO was increased from 1 to 250 Pa, at a constant NO partial pressure of 57.5 Pa. In a similar manner, the nitric oxide kinetic order varied continuously from +3/2 to -1 as the partial pressure of NO was increased from 1 to 1800 Pa, at a constant CO partial pressure of 44.0 Pa. The catalyst surface was characterized with Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), and thermal desorption spectroscopy (TDS). Initial Auger analysis revealed surface contamination by sulfur, phosphorus, and boron. These contaminants were removed via cycles of argon ion bombardment, reactive ion bombardment, and high-temperature annealing. Nitric oxide adsorbed with a high sticking coefficient and formed a c(2 x 2) ordered overlayer at saturation. The nitric oxide adsorbate dissociated upon slow stepwise heating as indicated by the production of a surface oxide and disappearance of surface nitrogen. Thermal desorption experiments at a faster heating rate indicated, however, that most of the adsorbed nitric oxide desorbed molecularly in a first-order process with a peak at 401 K during the temperature flash. Carbon monoxide adsorbs molecularly in two distinct sites with desorption from both following first-order kinetics with TDS peaks at 373 and 425 K. A kinetic model was developed which is consistent with both the steady-state kinetic and surface characterization results.

• Research Organization: Iowa State Univ., Ames (USA)
• OSTI ID: 5251044
• Journal Information: J. Catal.; (United States), Vol. 98:1
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
33 ADVANCED PROPULSION SYSTEMS
59 BASIC BIOLOGICAL SCIENCES
NITRIC OXIDE
REDUCTION
RHODIUM
CATALYTIC EFFECTS
AUGER ELECTRON SPECTROSCOPY
BORON
CARBON DIOXIDE
CARBON MONOXIDE
CATALYSTS
CHEMICAL REACTION KINETICS
DESORPTION
ELECTRON DIFFRACTION
MATHEMATICAL MODELS
NITROGEN
PHOSPHORUS
SULFUR
SURFACE CONTAMINATION
SYNTHESIS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
CONTAMINATION
DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTS
KINETICS
METALS
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
REACTION KINETICS
SCATTERING
SEMIMETALS
SPECTROSCOPY
TRANSITION ELEMENTS
400201* - Chemical & Physicochemical Properties
330701 - Emission Control- Nitrogen Oxides
550200 - Biochemistry