Re-investigating the CO oxidation mechanism over unsupported MnO, Mn2O3 and MnO2 catalysts

✍ Scribed by Kanaparthi Ramesh; Luwei Chen; Fengxi Chen; Yan Liu; Zhan Wang; Yi-Fan Han

• Book ID: 104009767
• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 444 KB
• Volume: 131
• Category: Article
• ISSN: 0920-5861
• DOI: 10.1016/j.cattod.2007.10.061

✦ Synopsis

Kinetic study of CO oxidation in combination with experiments of temperature-programmed oxidation (TPO) and reduction (TPR) have been performed on various unsupported crystalline manganese oxides (MnO x ); while the reactivity shows an order of MnO MnO 2 < Mn 2 O 3 in a mixture of unit ratio of O 2 /CO at/below 523 K. We propose that under the current conditions the interaction of adsorbed CO and O is mainly responsible for CO 2 formation on Mn 2 O 3 and MnO 2 catalysts, following either the Langmuir-Hinshelwood mechanism or Eley-Rideal mechanism. Meanwhile, direct evidence from transient CO oxidation suggests that the Mars-van-Krevelen mechanism may occur for all catalysts simultaneously, especially, it is predominant for the MnO catalyst. The evidence of structural modifications during reaction was confirmed by Raman spectra obtained from used MnO.