title: Oxidation of methane over palladium catalysts: effect of the support.
abstract: This work is focused on the deep catalytic oxidation of methane over supported palladium catalysts. The influences of the metal loading, oxidation state of palladium, nature of supports, presence of promoters in the supports (for zirconia-based supports), and thermal stability have been studied experimentally. Catalysts were prepared by incipient wetness of commercially available supports with aqueous solutions of palladium nitrate. For gamma-alumina support, it was observed that the optimal amount of palladium is between 0.5% and 2%, with higher amounts leading to a loss in specific activity. Concerning the oxidation state of the catalyst, it is concluded that for all the supports tested in the present work, a reduction of the catalyst is not needed, yielding the same conversion at steady state catalysts reduced and oxidised. The thermal stability of various supported catalysts were also studied, zirconia supports being the most active. These supports, specially Y-modified zirconia support, do not suffer appreciable deactivation below 500 degrees C.
authors.affiliation: Department of Chemical and Environmental Engineering, University of Oviedo c/Julián Clavería s/n, 33006 Oviedo, Spain.
authors.forename: Lara S
authors.initials: LS
authors.lastname: Escandón
authors.forename: Salvador
authors.initials: S
authors.lastname: Ordóñez
authors.forename: Aurelio
authors.initials: A
authors.lastname: Vega
authors.forename: Fernando V
authors.initials: FV
authors.lastname: Díez
mesh_terms: D000397:Air Pollution / Q000517:prevention & control*; D000537:Aluminum Oxide; D002384:Catalysis; D002849:Chromatography, Gas; D006358:Hot Temperature; D008697:Methane / Q000737:chemistry*; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D012822:Silicon Dioxide; D014025:Titanium; D015040:Zirconium
chemical_list: C009495:titanium dioxide; D010165:Palladium; D012822:Silicon Dioxide; D015040:Zirconium; D014025:Titanium; D000537:Aluminum Oxide; D008697:Methane; C028541:zirconium oxide