Accession Number : AD0666596

Title :   THERMAL DESORPTION OF CARBON MONOXIDE FROM NICKEL,

Corporate Author : BOEING SCIENTIFIC RESEARCH LABS SEATTLE WASH SOLID STATE PHYSICS LAB

Personal Author(s) : Smith,Alan W.

Report Date : FEB 1968

Pagination or Media Count : 58

Abstract : The adsorption of carbon monoxide on nickel has been studied by the thermal desorption technique. Thermal desorption peaks for states with activation energies of desorption of 13, 27, and 39 Kcal/mole have been identified. Other weakly adsorbing states were present but the peaks could not be resolved. Preparing the surface by oxidation and reduction and by argon ion bombardment gave thermal desorption curves similar in peak temperatures but not in peak heights. Two effects were noted with the runs where water pressure was appreciable in the system. It was necessary to heat the samples in carbon monoxide to obtain adsorption into the highest energy states and also carbon dioxide was observed with this carbon monoxide peak. These effects were attributed to the oxidation of the surface by the water vapor. It was also necessary to treat the sample strongly to remove carbon near the surface to obtain a stable clean surface. Annealing the ion bombarded surface increased the number of high energy (39Kcal) sites and decreased the number of moderate energy (27 Kcal) sites. The logarithm of the frequency factor was found to be a linear function of the square root of the activation energy for desorption. The presence of hydrogen when carbon monoxide is adsorbed at elevated temperatures gives rise to a new desorption peak between 600K and 700K. (Author)

Descriptors :   (*NICKEL, ADSORPTION), MONOMOLECULAR FILMS, CARBON MONOXIDE, MOLECULAR ASSOCIATION, REMOVAL, HEAT OF ACTIVATION, HEATING, WATER VAPOR, ANNEALING, SURFACE PROPERTIES, HYDROGEN, CATALYSTS

Subject Categories : Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE