Core-shell PdO@SiO2/Al2O3 with sinter-resistance and water-tolerance promoting catalytic methane combustion

An Al2O3-supported core-shell-structured PdO@SiO2 catalyst was rationally synthesized for lean-CH4 oxidation with outstanding water-tolerance and sinter-resistance properties. PdO@SiO2 works two parts in promoting the hydrothermally catalytic performance. Firstly, the core-shell configurations with maximized interface and intimate contact bring out the strong metal-support interaction, which leads to the benign oxidation-reduction property and the higher desorption rate of OH-/H2O over the PdO active centres; secondly, the SiO2 shells could isolate PdO nanoparticles from each other and protect them from agglomeration especially at high temperature (> 600 degrees C). As a result, PdO@SiO2/Al2O3 exhibits a 90% CH4 conversion at 380 degrees C, a low Ea value as 54.0 +/- 1.6 kJ/mol and an enhanced hydrothermal stability at 800 degrees C for 10 h. Such an interface-promoted core-shell-structured catalyst design strategy sheds some light on the stabilization and application of Pd-based catalysts.