Novel Pd/TiO 2–ZrO 2 catalysts for methane total oxidation at low temperature and their 18O-isotope exchange behavior

Abstract

TiO 2–ZrO 2 binary oxide supported palladium catalysts were prepared and evaluated for the catalytic combustion of methane at low temperature. Although XRD patterns of TiO 2–ZrO 2 binary oxides show individual anatase TiO 2 and monoclinic ZrO 2 peaks without shift, the combination of TiO 2 and ZrO 2 obviously favors the catalytic performance. Catalyst Pd/TiZr2 has activity much higher than Pd/TiO 2, even higher than Pd/ZrO 2, which is one of the most active catalysts for methane combustion. The results of TPR and 18O-isotope exchange experiments demonstrate that the excellent activity of Pd/TiZr2 is due to its high oxygen mobility and moderate reducibility, which is in accordance with our previous work. XPS results indicate that the dispersion of Pd has little influence on the catalytic activity.