Author(s)

Khouloud Sadouki¹, Shemseddine Fessi^1,2, Zouhaier Ksibi¹, Mickael Capron³, Franck Dumeignil³, Abdelhamid Ghorbel¹

¹Laboratoire de Chimie des Matériaux et Catalyse, Département de Chimie, Faculté des Sciences de Tunis, Université Tunis-El Manar, Campus Universitaire, Tunis, Tunisie.
²Chemistry Department, Faculty of Science and Arts, University of Jeddah, Jeddah, Saudi Arabia.
³Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181-UCCS-Unité de Catalyse et Chimie du Solide, Lille, France.

Aerogel Pd/(Ce_0.33Zr_0.66O₂)SiO₂ catalysts (CeZry) were prepared with variable Ce and Zr loadings (molar ratio Ce/Zr = 1/2) by combining sol-gel and impregnation methods. First, N₂-physisorption was used to investigate the texture evolution. Then, H₂-chimisorption and TEM were performed to study the effect on particle dispersion. After, TPR was used to determine the catalyst reducibility. Furthermore, XPS characterization was done to identify the palladium oxidation state and to evaluate the Pd-support interaction. Finally, the prepared catalysts were tested in methane combustion to assess their catalytic activity. The obtained results showed that, when the Zr and Ce loadings are varied between 0% and 8% and between 0% and 6% respectively, the BET surface area was increased from 615 to 744 m²/g, the porosity diameter from 45.7 to 83.6 Å, the Pd particle diameter from 5.2 to 7.0 nm, the CeO₂ and ZrO₂ particle size from 0 to 68 nm, the reduction temperature shift reached 16°C, the Pd binding energy shift attained 0.6 eV, but an optimum amounts of Zr (4 wt.%) and Ce (3 wt.%) are needed to maximize the PdO reducibility and to enhance the catalytic activity. In effect, 100% conversion of methane was reached at around 415°C on the CeZr4 catalyst.

Pd/(CexZr(1-x)O₂)/SiO₂ Catalysts, Methane Combustion, Catalytic Activity

Sadouki, K. , Fessi, S. , Ksibi, Z. , Capron, M. , Dumeignil, F. and Ghorbel, A. (2018) Effect of Zirconium and Cerium Loadings on Aerogel Pd-Based Catalysts for Methane Combustion. Advances in Materials Physics and Chemistry, 8, 105-119. doi: 10.4236/ampc.2018.83008.