Preparation of Pd/SiO2 Catalysts by a Simple Dry Ball-Milling Method for Lean Methane Oxidation and Probe of the State of Active Pd Species

A series of Pd/SiO2 catalysts were prepared with different Pd precursors by a dry ball-milling method and used in the catalytic oxidation lean methane at low temperature. The effect on performance was investigated state most active species probed. results indicate that is simple but rather effective to prepare for oxidation, palladium acetylacetonate an ideal precursor obtain highly Pd/SiO2-Acac catalyst well- stably dispersed species, owing tight contact between Si–OH SiO2 support. Besides size dispersion particles, also plays crucial role determining activity non-monotonic dependence observed. various follows order PdOx >> > PdO; PdOx/SiO2-Acac (in particular PdO0.82/SiO2-Acac when x = 0.82) exhibit much higher temperature than PdO/SiO2-Acac. PdOx/SiO2 may degrade during due gradual transformation PdO oxygen-rich ambiance; however, such degradation reversible degraded can be recovered through redox treatment regain species. This work helps foster better understanding relationship structure supported clarifying which should beneficial design