Effect of metal-metal and metal-support interaction on activity and stability of Pd-Rh/alumina in CO oxidation

[Display omitted] •Two series of Pd-Rh catalysts based on gamma and delta alumina were prepared.•Characterization of the catalysts by unique methods has been provided.•Metal-metal and metal-support interactions were shown to affect catalytic behavior.•Better initial activity and stability were attri...

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Published inCatalysis today Vol. 293-294; pp. 73 - 81
Main Authors Vedyagin, Aleksey A., Volodin, Alexander M., Kenzhin, Roman M., Stoyanovskii, Vladimir O., Shubin, Yury V., Plyusnin, Pavel E., Mishakov, Ilya V.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 15.09.2017
Subjects
Alumina
Bimetallic Pd-Rh catalysts
CO oxidation
Phase transformation
Stability
Phase transformation
Stability
CO oxidation
Alumina
Bimetallic Pd-Rh catalysts
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Summary:[Display omitted] •Two series of Pd-Rh catalysts based on gamma and delta alumina were prepared.•Characterization of the catalysts by unique methods has been provided.•Metal-metal and metal-support interactions were shown to affect catalytic behavior.•Better initial activity and stability were attributed to weak or lacking interaction.•Superior long-term stability was assigned to bimetallic Pd-Rh/γ-Al2O3 catalyst. A series of Pd-Rh/alumina catalysts with total precious metals loading of 0.2wt.% was prepared by means of mechanical mixing of monometallic precursors and incipient wetness impregnation of the support with dual complex salt. Gamma and delta alumina supports were obtained from commercial aluminum hydroxide by calcinations at 720 and 1000°C respectively. Supports were examined by electron paramagnetic resonance spectroscopy, low-temperature nitrogen adsorption, X-ray diffraction analysis and photoluminescence spectroscopy. It was shown that concentration of donor sites of the supports differs according to distinctions between values of their specific surface areas. Finally, the strength of metal-support interaction is getting much weaker in the case of δ-Al2O3. Bimetallic Pd-Rh species with strong metal-metal interaction supported on γ-Al2O3 were found to be characterized by superior high-temperature stability. Pd/Rh ratios of 3:2 and 7:3 were shown to be the most appropriate for this purpose.
ISSN:0920-5861
1873-4308
DOI:10.1016/j.cattod.2016.10.010