Oxidation of carbon monoxide over palladium on zirconia prepared from amorphous Pd-Zr alloy: II. The Nature of the active surface

Journal Article · Tue Sep 01 04:00:00 EDT 1992 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(92)90145-8· OSTI ID:7131399

Schloegl, R; Loose, G; Wesemann, M ^[1]; Baiker, A ^[2]

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1. Fritz Haber Inst. der Max-Planck Gesellschaft, Berlin (Germany)
2. Swiss Federal Inst. of Technology, Zurich (Switzerland)

The oxidation of dilute mixtures of CO with dilute oxygen to CO{sub 2} proceeds efficiently at moderate temperatures over a catalyst prepared from in-situ activation of amorphous (PdZr{sub 2}) alloys. The process of activation and the nature of the activated surface are investigated by XPS, UPS, and low pressure reaction experiments. It turned out to be crucial to perform the activation in situ in a special reaction chamber. The simultaneous presence of oxidizing and reducing components in the gas leads to the formation of particles of a solid solution of oxygen in Pd (Pd + O) in intimate contact to an ion conducting phase of zirconia. The interface between the two types of particles is large and influences the chemical stability of the Pd + O. It is performed in the rapid solidification process which leads to a disc-shaped morphology of the micrograins in the alloy. The arrangement is capable of storing chemically active oxygen. The superior catalytic performance of this system relative to a conventional impregnated Pd/ZrO{sub 2} catalyst is traced back to the intimate contact of the oxygen storage phase, zirconia, with the active phase, Pd + O, which is stabilized against reduction to the pure metal by a constant supply of oxygen ions through the bulk of the supporting matrix and the surface of the particle.

• OSTI ID: 7131399
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 137:1; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

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ALLOYS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL ACTIVATION
CHEMICAL PREPARATION
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
ELEMENTS
EMISSION
INTERFACES
METALS
MORPHOLOGY
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PALLADIUM
PALLADIUM ALLOYS
PALLADIUM COMPOUNDS
PALLADIUM OXIDES
PHOTOELECTRON SPECTROSCOPY
PHOTOEMISSION
PLATINUM METAL ALLOYS
PLATINUM METALS
RADIATIONS
SECONDARY EMISSION
SPECTROSCOPY
STABILITY
SURFACE PROPERTIES
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
ULTRAVIOLET RADIATION
X-RAY SPECTROSCOPY
ZIRCONIUM ALLOYS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES