Catalytic Oxidation of o-Xylene over Pd/Y-Al2O3 Catalysts

1% (w) Pd/Y-Al2O3 catalysts were prepared by the impregnation method using nanoY-Al2O3 (10 nm) and Y-Al2O3 (200-300 nm) as support materials. The catalysts were tested for catalytic oxidation of o-xylene and the difference of catalyst activity before and after hydrogen reduction was investigated. The results indicate that 1% (w) Pd/Y-Al2O3 (nano) has the highest catalytic activity for o-xylene oxidation after H-2 reduction, and the T-90 (The temperature of conversion rate of o-xylene reaches 90%) was 150 degrees C. The structure-activity relationships of the catalysts were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), while the specific surface area was determined using the Brunauer-Emmett-Teller (BET) isotherm. The results show that the reduced Pd is the active species for catalytic oxidation of o-xylene. Pd particle size has a significant influence on the catalyst activity and a small Pd particle size is favorable. There is a strong interaction between the supporter (nanoY-Al2O3) and the Pd species, which facilitates the particle size control and Pd dispersion, thereby increasing the catalyst activity of the 1% (w) Pd/Y-Al2O3(nano) catalyst