Enhanced properties of Pd/CeO 2 -nanorods modified with alkaline-earth metals for catalytic oxidation of low-concentration methane.

A series of Pd/CeO 2 -nanorods catalysts modified with alkaline-earth metals were prepared by the incipient impregnation method. Their catalytic properties in low-concentration methane oxidation were also investigated. The catalysts were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and H 2 -temperature-programmed reduction techniques. The catalytic results show that the Ca element doped in Pd/CeO 2 , with optimum molar ratio of Pd to Ca of 2 and calcination temperature of 450 °C, improved the properties of the Pd-based catalyst remarkably, which is attributed to strong Pd-support interaction and high oxygen mobility. Therefore, calcium is more suitable as a promoter for enhancing the activities of the Pd/CeO 2 catalyst in methane oxidation.