Importance of palladium dispersion in Pd/A(12)O(3) catalysts for complete oxidation of humid low-methane-air mixtures

• Type: Article in International Scientific Journal
• Date: 2008

Authors

Stasinska, B (Author) Other; Machocki, A (Author) Other; Antoniak, K (Author) Other; Rotko, M (Author) Other; José Luis Figueiredo (Author) FEUP; Goncalves, F (Author) Other

Journal

Title: Catalysis Today

Vol. 137

Pages: 329-334

ISSN: 0920-5861

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 25 Citations

ISI Web of Science

Scopus - 22 Citations

Scientific classification

FOS: Engineering and technology > Other engineering and technologies

CORDIS: Technological sciences

Other information

Authenticus ID: P-003-W3Z

DOI: 10.1016/j.cattod.2008.05.015

Abstract (EN): The catalytic oxidation is considered as an environmental benign method for utilization of various methane-poor gas mixtures, including humid post-ventilation air of coal mines. The small crystallites of palladium phase in the Pd/Al2O3 catalyst decrease temperatures necessary to ignite the methane oxidation reaction and to achieve complete conversion of methane. The isotopic exchange of oxygen between the catalyst and the gas phase, the temperature-programmed reduction (TPR) with methane and the X-ray photoelectron spectroscopy studies suggest that it can result from a higher number of the Pd-PdO sites present on the catalysts with small palladium crystallites. The inhibiting effect of water vapour present in the reaction mixture increases with lower dispersion of palladium phase as well as with the water concentration in the feed. The larger palladium crystallites are more significantly affected by the presence of water. It is suggested that water vapour blocks the Pd-PdO active sites. The catalysts with small crystallites (<6.6 nm) of palladium can be successfully used for mitigation of the emission of methane from coal mine post-ventilation air and, after increasing of the methane concentration to 12 vol.%, for its utilization for the energy production. In the case of such catalysts even a high concentration of water vapour has the least negative influence on the catalyst activity and it will not interfere with obtaining of the 100% conversion of methane below 650 degrees C. (C) 2008 Published by Elsevier B.V.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6