Reaction Mechanism of Aerobic Oxidation of Alcohols Conducted on Activated-Carbon-Supported Cobalt Oxide Catalysts

• Type: Article in International Scientific Journal
• Date: 2011

Authors

Junjiang J Zhu (Author) Other; Joaquim L Faria (Author) FEUP; Jose L Figueiredo (Author) FEUP; Arne Thomas (Author) Other

Journal

Title: Chemistry - A European Journal

Vol. 17

Pages: 7112-7117

ISSN: 0947-6539

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 42 Citations

ISI Web of Science

Scopus - 51 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-002-R46

DOI: 10.1002/chem.201003025

Abstract (EN): Catalytic performances and the reaction mechanism of Co(3)O(4)/AC (AC=activated carbon) for aerobic oxidation of alcohols carried out in the liquid phase were investigated. Co(3)O(4)/AC shows a high activity for aerobic oxidation of benzyl alcohol, comparable to noble metal catalysts (e. g., Au/AC) even in the absence of additives or promoters (e. g., NaOH). Changing preparation conditions, such as treatment temperature and/or time, can affect the catalytic performances of Co(3)O(4)/AC, due to decomposition of surface groups of the carbon support. Careful studies show that low alcohol conversions are obtained with either Co(3)O(4) or AC alone, which indicates that the high conversion observed over the Co(3)O(4)/AC is due to a synergistic effect between Co(3)O(4) and AC. Parallel experiments using a high-surface-area covalent triazine framework or oxygen-inert carbon nitride as support for the Co(3)O(4) catalyst also show lower conversions, which suggest that the ability of AC (in Co(3)O(4)/AC) to activate molecular oxygen is essential for the reaction. FTIR and XPS spectra taken from catalysts before and after the reaction confirm that oxygen activation proceeds mainly on the carbon support. As a result, it can be assumed that the alcohol dehydrogenation step proceeds on the metal oxide, whereas the oxygen activation step occurs mainly on the carbon support.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6