Sol gel derived Pd/Al2O3-ZrO2 as catalysts for methane combustion: Effect of zirconium loading

Abstract

A series of Pd/Al2O3-ZrO2 materials have been prepared via sol gel method as an attractive route to obtain more homogeneous binary oxides Al2O3-ZrO2. A Zr loading between 2 and 15 wt% was used to investigate the Zr promotion of Pd/Al2O3 materials. The prepared catalysts were calcined at two different temperatures. Very interesting results have been obtained at low zirconium content. A small amount of Zr is seen to be sufficient to stabilize the activity and to obtain good catalytic performances with developed textural properties compared to conventional catalysts used to oxidize methane. The increase of the zirconium loading is seen to decrease the catalytic activity may be due to the development of tetragonal zirconia phase detected by XRD. Similar effect has been observed after heating catalysts at high temperatures. A loss in BET surface area and in metal dispersion has been also observed for zirconium rich catalysts. A contradictory effect on textural and structural properties is seen after their calcination at 700 °C. © 2010 Springer Science+Business Media, LLC.