Methane oxidation over palladium on zirconia prepared from amorphous Pd[sub 1]Zr[sub 3] alloy
- Paul Scherrer Institut, Villigen (Switzerland)
- Swiss Federal Institute of Technology, Zuerich (Switzerland)
Catalysts for methane oxidation have been prepared by oxidation of amorphous Pd[sub 2]Zr[sub 3] metal alloy under different conditions. A sequence of chemical and morphological changes occurring during the alloy oxidation process leads to highly active microporous palladium/zirconia catalysts suitable for the deep oxidation of methane. Depending on the activation temperature, distinct PdO species interacting with zirconia exist in these catalysts, as revealed by oxygen desorption and thermoanalytical measurements. Smaller PdO species were found to decompose at a markedly higher temperature than larger PdO species, which only interact weakly with the support. Kinetic studies were carried out in a fixed-bed microreactor at temperatures of 400-800 K and atmospheric pressure using a reactant mixture with a ratio CH[sub 4]:O[sub 2] = 1:4. Turnover frequencies, based on the exposed palladium surface atoms determined by CO chemisorption, were more than two times higher than those of palladium on zirconia catalysts prepared by impregnation or by coprecipitation. Methane oxidation measurements carried out over the conventionally prepared palladium/zirconia catalysts and a corresponding catalyst derived from Pd[sub 1]Zr[sub 3] showed CO and H[sub 2] selectivities higher than 90% under reducing conditions, i.e., with a reactant ratio CH[sub 4]:O[sub 2] = 8:1 at 870 K. 29 refs., 12 figs., 4 tabs.
- OSTI ID:
- 6153459
- Journal Information:
- Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 141:2; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
034000 -- Natural Gas-- Combustion
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKANES
ALLOYS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSIS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CHEMISORPTION
COPRECIPITATION
DESORPTION
ELEMENTS
HETEROGENEOUS CATALYSIS
HYDROCARBONS
METALS
METHANE
MORPHOLOGICAL CHANGES
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PALLADIUM
PALLADIUM ALLOYS
PLATINUM METAL ALLOYS
PLATINUM METALS
PRECIPITATION
SEPARATION PROCESSES
SORPTION
SYNTHESIS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
TRANSITION ELEMENTS
ZINC COMPOUNDS
ZINC OXIDES
ZIRCONIUM ALLOYS
ZIRCONIUM BASE ALLOYS