Exploration of Mn incorporated CeO2 nanoflakes with meso- and macropores for the effective simultaneous catalytic oxidation of carbon monoxide and propane

• Published in: Reaction kinetics, mechanisms and catalysis mechanisms and catalysis, 2019-08, Vol.127 (2), p.775-785
• Main Authors: Padikkaparambil, Silija, Sugunan, Sankaran, Narayanan, Binitha N.
• Format: Article
• Language: English
• Subjects: Catalysis; Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Physical Chemistry
• ISSN: 1878-5190; 1878-5204
• DOI: 10.1007/s11144-019-01601-0

Highly porous ceria nanoflakes are prepared by a facile citric acid assisted sol–gel method. A Mn incorporated solid solution of CeO 2 was also efficiently developed without disturbing the nanoflake morphology of pure CeO 2 . The formation of fluorite CeO 2 with crystallite size ranging from 5–8 nm is evidently revealed from XRD analysis. The introduction of Mn to CeO 2 resulted in the formation of smaller crystallites of CeO 2 with reduced particle size and lattice parameters. SEM images displayed the flake like nature of CeO 2 and Mn/CeO 2 with meso and macro pores. TEM images confirm the pore size reduction of CeO 2 with Mn doping which is already indicated from BET-BJH-surface area and pore-volume analysis. The presence of a large amount of oxygen vacancies in CeO 2 upon Mn introduction is indicated from the drastic reduction in the peak intensities in the Raman spectrum. XPS results revealed that Ce exists in its +4 oxidation state whereas Mn exists in its +3 oxidation state, both of which are favorable for oxidation reactions. The catalytic performance of the prepared nanoflakes is investigated in the simultaneous oxidation of CO and C 3 H 8 . Mn incorporated CeO 2 showed 100% oxidation of CO from 300 °C onwards and 84% hydrocarbon oxidation is observed even at a high gas flow rate of 500 ml/min at 400 °C over 0.5 g of the catalyst.