Characterization and study on the thermal aging behavior of palladium–alumina catalysts

Aleksey A. Vedyagin, Alexander M. Volodin, Roman M. Kenzhin, Vladimir O. Stoyanovskii, Vladimir A. Rogov, Dmitrii A. Medvedev, Ilya V. Mishakov

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9 Citations (Scopus)

Abstract

A series of Pd/Al2O3 catalysts were prepared by incipient wetness impregnation method. Palladium loading was varied in a range of 0.125–4.0 mass%. The catalytic performance of the samples was tested in model reaction of CO oxidation at oxygen excess. Catalysts were characterized by temperature-programmed reduction (TPR), electron paramagnetic resonance, and UV–visible spectroscopy. Thermal aging of chosen samples was performed at 1000 °C. The thermal aging behavior was studied using TPR, X-ray diffraction analysis, transmission electron microscopy, and X-ray photoelectron spectroscopy (XPS). It was shown that palladium stabilized in the form of dispersed surface Pd2+ species when Pd loading is 0.5 mass% and below. Samples with higher loading preferentially contain nanosized Pd particles. Agglomeration of Pd species during thermal aging was found to take place starting from Pd concentration of 1.0 mass%. In some cases, size of Pd particles exceeds 150 nm, which is in about 40 times higher comparing with the initial samples. According to XPS data, degree of Pd2+-alumina interaction in the aged samples is also increased.

Original languageEnglish
Pages (from-to)1-10
Number of pages10
JournalJournal of Thermal Analysis and Calorimetry
DOIs
Publication statusAccepted/In press - 19 Jun 2017

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Keywords

  • Alumina
  • CO oxidation
  • Palladium
  • Thermal aging
  • TPR

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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