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

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.