Surface science studies of catalyzed methanol synthesis on model copper and Cu-Zn-O surfaces

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5601973

Fu, S S

Cu-Zn-O surfaces that are catalysts for methanol synthesis from CO, CO[sub 2], and H[sub 2] are modeled using zinc oxide overlayers on copper single crystals. These studies were performed in ultra-high vacuum (UHV) utilizing Temperature Programmed Desorption, Auger Electron Spectroscopy, and Low Energy Electron Diffraction techniques. The chemisorption of O[sub 2], CO, CO[sub 2], and D[sub 2] were compared on a stepped Cu(311), and a flat Cu(110). At low pressures ([approximately]10[sup [minus]6] Torr), Cu(311) was found to be much more reactive than Cu(110) for the dissociative adsorption of CO[sub 2] and D[sub 2], and the formation of CO[sub 2] from surface oxygen and CO. Since these reactions are important in methanol synthesis, these results suggest that methanol synthesis over copper may be a structure sensitive reaction. The interaction of copper, zinc, and oxygen were examined by the deposition of submonolayers to multilayers of zinc and oxygen in UHV on Cu(110). Carbon monoxide adsorbs well on copper at 150 K and low pressures (<10[sup [minus]6] Torr), but only poorly on the oxides of copper and zinc. Carbon dioxide adsorbs on ZnO at 150 K and low pressures (<10[sup [minus]6] Torr), but not on copper or oxidized copper. The authors used a combination of CO and CO[sub 2] adsorption to follow the initial growth of two-dimensional ZnO[sub x] islands and the effect of heat and oxygen treatments on these islands. Heating above 300 K leads irreversibly to three-dimensional island formation. The interaction of methanol with model Cu-Zn-O surfaces was also studied. Oxygen was adsorbed onto the exposed copper part of the surfaces to form ZnO[sub x]/y ML O/Cu(110) surfaces. The roles of ZnO[sub x] islands and chemisorbed oxygen on copper were investigated by monitoring methanol decomposition, into surface formate and methoxy species.

• Research Organization: California Univ., Berkeley, CA (United States)
• OSTI ID: 5601973
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
100200 -- Synthetic Fuels-- Production-- (1990-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical &amp; Physicochemical Properties
ALCOHOLS
AUGER ELECTRON SPECTROSCOPY
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CHEMISORPTION
COHERENT SCATTERING
COPPER
COPPER COMPOUNDS
COPPER OXIDES
DESORPTION
DEUTERIUM
DIFFRACTION
ELECTRON DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTS
HYDROGEN ISOTOPES
HYDROXY COMPOUNDS
ISOTOPES
LIGHT NUCLEI
METALS
METHANOL
MILLER INDICES
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
SCATTERING
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
SPECTROSCOPY
STABLE ISOTOPES
SURFACE PROPERTIES
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
ZINC COMPOUNDS
ZINC OXIDES