Methane Oxidation over PdO: Towards a Better Understanding of the Influence of the Support Material

This work investigates the behavior of PdO-based catalysts on different support materials such as Al₂O₃, CeO₂, SnO₂, and ZrO₂ and their activity for methane oxidation under lean conditions. In addition, global kinetics are used to simulate and differentiate the experimental activity data with a fixed bed flow reactor model.

Abstract

The presence of water vapor during the oxidation of the strong greenhouse gas methane over PdO-based catalysts is known to result in severe inhibition and catalyst deactivation. In this context, our current study elucidates the role of the support material for different water concentrations in the reaction gas mixture. Compared to a reference PdO/Al₂O₃ catalyst, the catalytic activity can be significantly enhanced when using SnO₂ and ZrO₂ as support materials and remains stable during 24 h of operation at 823 K in the presence of 12 % H₂O, whereas under identical conditions CH₄ conversion drops by 68 % over PdO/Al₂O₃. The interplay between Pd species and catalyst support was systematically characterized by thermogravimetric analysis, temperature-programmed reduction experiments and TEM measurements. Finally, a kinetic scheme was derived based on the experimental data.

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