Surface science investigation of the water-gas shift reaction on Cu(111)

Journal Article · Sun Mar 01 00:00:00 EST 1987 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(87)90341-1· OSTI ID:5450008

Campbell, C T; Daube, K A

The authors have studied the kinetics of the water-gas shift reaction on a clean Cu(111) single-crystal surface using an apparatus which allows rapid transfer of the catalyst between a microreactor and an ultrahigh-vacuum chamber for surface preparation and postreaction surface analyses (AES), XPS, LEED). At 10 Torr H/sub 2/O, 26 Torr CO, and 612 K, the reaction proceeds with an activation energy of 17 kcal/mole and reaction orders in H/sub 2/O and CO pressures of zero and 0.5-1.0, respectively. The surface appears completely metallic and relatively free of adsorbed species in postreaction analysis, even when heavily preoxidized. The kinetics compare favorably with data for high-surface-area Cu/ZnO or Cu-based catalysts, indicating that metallic Cu is the active ingredient in these. The rate is limited by dissociative adsorption of water under their conditions. The authors were unable to produce significant coverages of oxygen species on Cu(111) by dosing pure H/sub 2/O at 10 Torr and 500-650 K. The mechanism is discussed in light of surface science measurements on Cu surfaces. The Cu(111) surface was also dosed with Zn from aqueous solution, and the resulting ZnO/sub x/Cu(111) surfaces were tested for activity as water-gas shift catalysts. No marked changes in activity compared to clean Cu(111) were observed. A new method for increasing gas chromatographic sensitivities for low sampling pressures (< 1 atm) is also described. 46 references.

• Research Organization: Indiana Univ., Bloomington
• OSTI ID: 5450008
• Journal Information: J. Catal.; (United States), Vol. 104:1
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
10 SYNTHETIC FUELS
AMMONIA
SYNTHESIS
COPPER
CATALYTIC EFFECTS
HYDROGEN PRODUCTION
WATER GAS PROCESSES
CHEMICAL REACTION KINETICS
ACTIVATION ENERGY
AUGER ELECTRON SPECTROSCOPY
CARBON MONOXIDE
ELECTRON DIFFRACTION
GAS CHROMATOGRAPHY
PHOTOELECTRON SPECTROSCOPY
SURFACE PROPERTIES
WATER
X-RAY SPECTROSCOPY
ZINC
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CHROMATOGRAPHY
COHERENT SCATTERING
DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY
HYDRIDES
HYDROGEN COMPOUNDS
KINETICS
METALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SCATTERING
SEPARATION PROCESSES
SPECTROSCOPY
TRANSITION ELEMENTS
080104* - Hydrogen- Production- Water Gas Processes
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