Probing the functionality of nanostructured MnCeOx catalysts in the carbon monoxide oxidation: Part II. Reaction mechanism and kinetic modelling

Francesco Arena, Roberto Di Chio, Layla Filiciotto, Giuseppe Trunfio, Claudia Espro, Alessandra Palella, Antonio Patti, Lorenzo Spadaro

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7 Citations (Scopus)

Abstract

The kinetics of the CO oxidation on a typical nanocomposite MnCeOx catalyst (M5C1) were probed by temperature programmed catalytic reaction (TPCR) tests in the range of 293–533 K, varying reagent partial pressure (i.e., pCO and pO2) between 0.00625 and 0.025 atm (P, 1 atm). Experimental data indicate kinetic orders of 0.6 and 0.4 on pCO and pO2 respectively, with apparent activation energy of 40 ± 3 kJ/mol. A systematic study of the interaction pattern of catalyst with reagent and product molecules shows easy reactivity of surface oxygen to CO, low mobility of lattice oxygen and weak surface affinity to CO2. Systematic evidences on reaction mechanism and surface intermediates signal an extrafacial redox path, triggered by abstraction of oxygen atoms in the neighbouring of active MnIV sites, and sustained by O2 species adsorbed on those surface oxygen vacancies. A Langmuir-Hinshelwood (L-H) reaction mechanism leads to a formal kinetic model explaining the CO oxidation functionality of bare and promoted MnOx catalysts.

Original languageEnglish
Pages (from-to)803-809
Number of pages7
JournalApplied Catalysis B: Environmental
Volume218
DOIs
Publication statusPublished - 5 Dec 2017

Keywords

  • Active sites and oxygen species
  • CO oxidation
  • Kinetic modelling
  • Nanostructured MnCeO catalyst
  • Reaction mechanism

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