Catalytic properties of Pd-supported hexaaluminate catalysts for high-temperature catalytic combustion
- Kyushu Univ., Kasuga, Fukuoka (Japan)
The catalytic properties of palladium supported on hexaaluminates (Sr[sub 0.8]La[sub 0.2]XAl[sub 11]O[sub 19], X = Al and Mn) was studied for use in high-temperature catalytic combustion. The activity of Pd/Sr[sub 0.8]La[sub 0.2]Al[sub 12]O[sub 19] increased initially with a rise in temperature, but decreased at high temperatures (ca. 700[degrees]C). The drop in catalytic activity became pronounced when the supported Pd particles were sintered into large agglomerates after calcination above 1000[degrees]C. From in situ XRD, TPD, and TPRO, it was revealed that the activity drop accompanies dissociation of PdO into metallic Pd species. Since the dissociation of PdO is a thermodynamic function of oxygen partial pressure, the temperature at the conversion drop appeared to be influenced by the oxygen concentration in the combustion reaction. The dissociation of PdO appears to result in removal of adsorbed oxygen species necessary for the catalytic reaction. On the other hand, such a significant drop in catalytic activity can be avoided by the use of Mn-substituted hexaaluminate (X = Mn) as a catalyst support. The catalytic activity of Mn-substituted hexaaluminate is effective in compensating for the drop in activity of Pd so that a stable combustion reaction can be attained in a whole temperature range. 17 refs., 11 figs., 1 tab.
- OSTI ID:
- 5600532
- Journal Information:
- Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 142:2; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
Similar Records
Role of A- and B-cations in catalytic property of substituted hexaaluminate (ABAl{sub 11}O{sub 19-{alpha}}) for high temperature combustion
Catalytic combustion over hexaaluminates
Related Subjects
034000 -- Natural Gas-- Combustion
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ALKALINE EARTH METAL COMPOUNDS
ALKANES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CALCINATION
CATALYSIS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
COMBUSTION
COMPLEXES
CONCENTRATION RATIO
DECOMPOSITION
DESORPTION
DIFFRACTION
DISSOCIATION
ELEMENTS
HETEROGENEOUS CATALYSIS
HYDROCARBONS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
MANGANESE COMPOUNDS
MANGANESE OXIDES
METHANE
NONMETALS
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PALLADIUM COMPLEXES
PARTICLES
PYROLYSIS
RARE EARTH COMPOUNDS
SCATTERING
SORPTION
STOICHIOMETRY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION