Dependence of Synergetic Effect of Palladium-Manganese-Hexaaluminate Combustion Catalyst on Nature of Palladium Precursor Full article
Journal |
Topics in Catalysis
ISSN: 1022-5528 , E-ISSN: 1572-9028 |
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Output data | Year: 2012, Volume: 55, Number: 11-13, Pages: 818-836 Pages count : 28 DOI: 10.1007/s11244-012-9874-3 | ||||
Tags | Manganese-hexaaluminate, Methane combustion, Palladium oxide, Palladium precursor, Pd-catalyst, Synergetic effect | ||||
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Abstract:
A synergetic effect in the methane oxidation activity of palladium and manganese hexaaluminate was studied over Pd-modified manganese-hexaaluminate catalysts, prepared by incipient wetness impregnation and calcined at 1200oC. The magnitude of the synergetic effect is found to be depends on the palladium precursor: it is higher for palladium nitrate and palladium acetate than for tetrachloropalladic acid.
The Pd/MnLaAl11O19 catalysts were characterized by X-ray diffraction, X-ray microanalysis, transmission electron microscope and temperature-programmed reduction with hydrogen. These data were compared with the properties of Pd/Al2O3 catalysts. At variation of Pd-precursors, a minor trend to the decrease of the Pd particle size was observed at transition from the ex-chloride Pd/MnLaAl11O19 catalyst with uniform Pd-distribution profile to the ex-nitrate and ex-acetate catalysts with egg-shell Pd-distribution. Slightly smaller size of metal palladium particles in the ex-nitrate and ex-acetate catalysts leads to the formation of larger amount of PdO dispersed on their surface during oxygen-pretreatment in H2-TPR experiments (Pd/PdO atomic ratio was 1/4) and under methane-oxidation mixture in comparison with ex-chloride catalysts (Pd/PdO = 4/1). The palladium addition to manganese-hexaaluminate changes strongly its redox properties, as result Mn3+ reduction to Mn2+ take place about 100 oC below that of pure hexaalunimate. The latter indicate probably on the higher oxygen mobility in Pd-modified manganese-hexaaluminate.
A higher PdO/Pd ratio formed in the ex-nitrate and ex-acetate Pd-modified manganese-hexaaluminate catalysts together with the high oxygen mobility provide the synergetic effect in methane oxidation activity at light-off temperature region. The high catalytic activity of manganese-hexaaluminate ensures methane combustion efficiency of the Pd-modified manganese-hexaaluminate catalysts at temperature above 700oC.
Cite:
Yashnik S.A.
, Ismagilov Z.R.
Dependence of Synergetic Effect of Palladium-Manganese-Hexaaluminate Combustion Catalyst on Nature of Palladium Precursor
Topics in Catalysis. 2012. V.55. N11-13. P.818-836. DOI: 10.1007/s11244-012-9874-3 WOS Scopus РИНЦ
Dependence of Synergetic Effect of Palladium-Manganese-Hexaaluminate Combustion Catalyst on Nature of Palladium Precursor
Topics in Catalysis. 2012. V.55. N11-13. P.818-836. DOI: 10.1007/s11244-012-9874-3 WOS Scopus РИНЦ
Dates:
Submitted: | Jul 25, 2012 |
Published online: | Jul 25, 2012 |
Published print: | Aug 1, 2012 |
Identifiers:
Web of science | WOS:000307778600015 |
Scopus | 2-s2.0-84867089286 |
Elibrary | 18753519 |
Chemical Abstracts | 2012:1087530 |
Chemical Abstracts (print) | 157:360364 |
OpenAlex | W2007822965 |