CO oxidation over Pd and Cu catalysts. IV. Prereduced Al sub 2 O sub 3 -supported copper

Journal Article · Sun Sep 01 00:00:00 EDT 1991 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(91)90320-4· OSTI ID:5536248

Choi, K I; Vannice, M A ^[1]

---

1. Pennsylvania State Univ., University Park (United States)

A study of the kinetics for CO oxidation over supported, prereduced Cu crystallites showed that it is close to first order in CO and near zero order in O{sub 2} at temperatures around 400 K. In situ IR measurements under reaction conditions revealed a clear first-order dependence on chemisorbed CO and an absence of activity when no adsorbed CO was detected; thus an Eley-Rideal mechanism is eliminated and a Langmuir-Hinshelwood surface reaction between adsorbed CO molecules and chemisorbed oxygen is strongly supported. These Cu/Al{sub 2}O{sub 3} catalysts were more active than Pd/Al{sub 2}O{sub 3} catalysts, and the average turnover frequency of 0.016 s{sup {minus}1} at 400 K and 26 Torr CO was about four times higher than the average value on Pd. An invariant IR band at 2,118 cm{sup {minus}1} for Co was very near that of 2,115 cm{sup {minus}1} reported for CO adsorbed on an oxidized Cu(111) surface and therefore was consistent with the near-saturation oxygen coverage indicated from the kinetic behavior. Analysis of the Ir spectra at various temperatures allowed a heat of adsorption of 7.2 kcal/mol to be determined under reaction conditions. An activation energy of 22-27 kcal/mol was estimated for the rate-determining step, i.e., the surface reaction, which is somewhat higher than that reported for adsorbed CO and submonolayer coverages of oxygen on Cu single crystals.

• OSTI ID: 5536248
• Journal Information: Journal of Catalysis; (United States), Vol. 131:1; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
33 ADVANCED PROPULSION SYSTEMS
CARBON MONOXIDE
OXIDATION
COPPER
CATALYTIC EFFECTS
PALLADIUM
ACTIVATION ENERGY
ADSORPTION HEAT
AIR POLLUTION CONTROL
ALUMINIUM OXIDES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC CONVERTERS
CHEMICAL REACTION KINETICS
CHEMISORPTION
COMBUSTORS
COMPARATIVE EVALUATIONS
INFRARED RADIATION
INFRARED SPECTRA
KINETIC EQUATIONS
SPECTROSCOPY
SURFACE PROPERTIES
TEMPERATURE RANGE 0273-0400 K
ALUMINIUM COMPOUNDS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CONTROL
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY
ENTHALPY
EQUATIONS
EQUIPMENT
EVALUATION
KINETICS
METALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLATINUM METALS
POLLUTION CONTROL
POLLUTION CONTROL EQUIPMENT
RADIATIONS
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
SPECTRA
TEMPERATURE RANGE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)
330702 - Emission Control- Carbon Monoxide