Abstract
The Pd/ZrO2-SiO2-Al2O3 catalysts are prepared by sol-gel synthesis (SG) and by combining sol-gel and solid exchange methods (SG-SE), with variable Si and Zr loadings. N2-physisorption, NH3-TPD and CH4-TPR are the main techniques used to characterise these catalysts. Furthermore, the total methane oxidation is used to test their catalytic activity. Compared to the SG sample, better BET surface area, higher pore volume and larger average pore diameter are obtained on the the SG-SE catalyst. In addition, similar acidity and PdO reducibility are obtained on these two solids. Moreover, the slightly higher activity observed on the SG catalyst seems to be due to its better PdO dispersion. However, the significant differences of texture, acidity and PdO reducibility should be the reasons for the catalytic activity variations on the catalysts prepared by SG-SE method with variable Si and Zr loadings.