Structure-dependent activity of CeO2 supported Ru catalysts for CO2 methanation

Tushar Sakpal, Leon Lefferts* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

22 Citations (Scopus)
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Abstract

In this study, CeO2 rods (CeO2/r), cubes (CeO2/c) and octahedra (CeO2/o) supported catalysts with identical Ru particle size were prepared. Trend in the activity of these catalysts for CO2 methanation was compared with the trend in their oxygen vacancy concentration measured after calcination. Ru/CeO2/r outperforms the other two catalysts with a reaction rate of 11.0 × 10−8 mols-1mRu -2 and selectivity to methane of 99% at 250 °C. Temperature-programmed reduction (TPR), Raman and X-ray photoemission spectroscopy (XPS) results confirms that Ru addition enhances reduction of CeO2. Also, Ru/CeO2/r is more reducible and contains more oxygen vacancies as compared to Ru/CeO2/o and Ru/CeO2/c, both after calcination as well as under reducing conditions. H2 consumption during TPR shows removal of oxygen equivalent to about 3 monolayers, implying diffusion of vacancies into the subsurface or bulk of CeO2. The catalyst with the highest concentration of oxygen vacancies is also the most active catalyst, suggesting that reactive adsorption CO2 at an oxygen vacancy is the rate determining step.

Original languageEnglish
Pages (from-to)171-180
Number of pages10
JournalJournal of catalysis
Volume367
DOIs
Publication statusPublished - 1 Nov 2018

Keywords

  • UT-Hybrid-D
  • CO methanation
  • Oxygen vacancy concentration
  • Ru particle size
  • Structure-activity relationship
  • CeO nano-shapes

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