title: Effect of pretreatment on pd/Al2O3 catalyst for catalytic oxidation of o-xylene at low temperature.
abstract: The effect of pretreatment on Pd/Al2O3 catalysts for the catalytic oxidation of o-xylene at low temperature was studied by changing the pretreatment and testing conditions. The fresh and pretreated Pd/Al2O3 catalysts were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The results showed that the pretreatment dramatically changed the Pd/PdO ratio and then significantly affected the Pd/Al2O3 activity; while the pretreatment had not much influence on Pd particle size. The Pd/Al2O3 pre-reduced at 300 degrees C/400 degrees C, which has fully reduced Pd species, showed the highest activity; while the fresh Pd/Al2O3, which has fully oxidized Pd species, presented the worst performance, indicating the Pd chemical state plays an important role in the catalytic activity for the o-xylene oxidation. It is concluded that metallic Pd is the active species on the Pd/Al2O3 catalyst for the catalytic oxidation of o-xylene at low temperature.
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. syhuang@rcees.ac.cn
authors.forename: Shaoyong
authors.initials: S
authors.lastname: Huang
authors.forename: Changbin
authors.initials: C
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: He
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D002384:Catalysis; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D013696:Temperature; D014961:X-Ray Diffraction; D014992:Xylenes / Q000737:chemistry*
chemical_list: D014992:Xylenes; D010165:Palladium; D000537:Aluminum Oxide; C026114:2-xylene