Adsorption of CO and CO sub 2 on clean and cesium-covered Cu(110)

Journal Article · Thu Jun 29 04:00:00 EDT 1989 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100350a040· OSTI ID:7197795

Rodriguez, J A; Clendening, W D; Campbell, C T ^[1]

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1. Indiana Univ., Bloomington (USA)

The interactions of Cs with Cu(110) and the coadsorption of CO and CO{sub 2} with Cs on Cu(110) have been studied with X-ray photoelectron spectroscopy, Auger electron spectroscopy, work function measurements, and thermal desorption mass spectroscopy (TDS). Cesium adsorbs in relatively cationic form at low coverages, depolarizing to relatively neutral, bulklike Cs by one close-packed monolayer ({theta}{sub Cs}* = 1.0). At low {theta}{sub Cs}*, indirect interactions stabilize CO{sub a} by {approximately} 15% relative to its desorption temperature ({approximately} 220 K) from clean Cu(110). For {theta}{sub Cs}* > 0.5, a CO{sub a}-Cs{sub a} complex appears, which decomposes at 400-500 K with simultaneous Cs and CO evolution in TDS. For a fixed CO dose, the concentration of this complex increases with {theta}{sub Cs}*, reaches a maximum at {theta}{sub Cs}* {congruent} 1.1, and decreases rapidly to zero at {theta}{sub Cs}* = 2.0. No CO will adsorb on Cs multilayers at 110 K. No CO{sub 2} adsorption could be detected on clean Cu(11) at 110 K. A cesium/carbonate surface complex is formed already from the lowest Cs coverages and all higher Cs coverages below 180 K via 2CO{sub 2g} + Cs{sub a} {yields} CO{sub a} = Cs {times} CO{sub 3,a} (perhaps through an O{sub a} or oxalate intermediate). Weakly adsorbed CO{sub 2} is also seen when Cs{sub a} is present, desorbing at {approximately} 130 K. The Cs {times} CO{sub 3,a} complex decomposes in a complex TDS spectrum at 500-700 K via Cs {times} CO{sub 3,a} {yields} Cs{sub a} + CO{sub 2,g} + O{sub a}. Cs{sub a} then desorbs at high coverages simultaneous to CO{sub 2} evolution. The implications of these results to Cs promotion of catalytic water-gas shift and methanol synthesis over Cu are discussed.

• OSTI ID: 7197795
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 93:13; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

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ADSORPTION
ALKALI METALS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CESIUM
CHALCOGENIDES
COPPER
DATA
ELECTRON SPECTROSCOPY
ELEMENTS
EXPERIMENTAL DATA
INFORMATION
MEASURING INSTRUMENTS
MEASURING METHODS
METALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
SORPTION
SPECTROSCOPY
TRANSITION ELEMENTS