Effect of Pt Addition on Methane Oxidation Activity of Pd-Mn-Hexaaluminate Catalysts
Wide interest to the catalytic combustion chamber of gas turbines stimulates search of new Pd-catalysts with respect to decrease of the light-off temperature, increase of the efficiency in hydrocarbon fuels combustion and thermal stability. Here we studied an effect of Pt to improve catalytic performance of the high-temperature Pd-Mn-hexaluminate catalysts in methane oxidation, especially in 1000 ppm SO2 and 3 wt.% water presence, and compared them with the properties of Pd/Al2O3 catalysts. The Redox properties (H2-TPR), particle morphology (HRTEM), composition and active sites (XRD, FTIR, XPS, O2-TPR, DTA) of the initial and spent catalysts were examined in order to find a reason of high efficiency and thermal stability of the catalyst. When Pt/Pd ratio was close to 0.25, the Pt addition modified water and SO2 resistant of Pd-Mn-hexaaluminate without decreasing its methane oxidation activity. Such performance of the catalyst can be explained by the formation of both PdO and PtPd-alloy.