Temperature-programmed desorption studies of the interactions of H[sub 2], CO, and CO[sub 2] with Cu/SiO[sub 2]

Journal Article · Mon Nov 01 04:00:00 EST 1993 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1993.1326· OSTI ID:5037311

Sandoval, M J; Bell, A T ^[1]

---

1. Lawrence Berkeley Laboratory, CA (United States)

The interactions of H[sub 2], CO, and CO[sub 2] with a Cu/SiO[sub 2] catalyst have been investigated using temperature-programmed desorption spectroscopy. The heats of adsorption of H[sub 2] and CO were obtained from analysis of the experimentally observed spectra, and the activation energy for H[sub 2] adsorption was obtained from isothermal measurements of the adsorption rate. The heat of adsorption of H[sub 2] increases from isothermal measurements of the adsorption rate. The heat of adsorption of H[sub 2] increases from 10.1 to 13.8 kcal/mol for 0.07 [<=] [theta][sub H] [<=] 0.26. The activation energy for H[sub 2] adsorption is 10.5 kcal/mol, and the activation energy for H[sub 2] desorption increases from 20.6 to 24.3 kcal/mol for 0.07 [<=] [theta][sub H] [<=] 0.26. The heat of adsorption of CO decreases with coverage from 16.4 to 12.5 kcal/mol for 0.01 [<=] [theta][sub CO] [<=] 0.18. The coverage by molecularly adsorbed CO[sub 2] was below the detectable limits for adsorption temperatures above 250 K. Evidence was found, however, for a small amount of dissociatively adsorbed CO[sub 2]. The present findings are in a very good agreement with recent studies on Cu single-crystals surfaces. 72 refs., 9 figs., 4 tabs.

• OSTI ID: 5037311
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 144:1; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical &amp; Physicochemical Properties
ABSORPTION HEAT
ACTIVATION ENERGY
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CHALCOGENIDES
COMPLEXES
COPPER COMPLEXES
DESORPTION
ELEMENTS
ENERGY
ENTHALPY
HEAT
HYDROGEN
MINERALS
NONMETALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPLEXES