关键词: Pd/γ-Al2O3, 苯, 催化降解, 化学态, 晶体结构

Abstract: The effects of various atmospheres (oxidative，reducing and inert atmosphere） pretreatment on the catalytic activity of Pd/γ-Al2O3 catalyst in benzene degradation were studied in this paper. The property of the catalyst was characterized by X-ray photoelectron spectroscopy (XPS)，X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis，and a possible influence mechanism of reducing，oxidative，and inert atmosphere pretreatment on the catalytic activity of Pd/γ-Al2O3 catalyst was proposed. The experimental results revealed that the pretreatment with reducing and inert atmosphere has a significant positive effect on the catalytic activity in benzene oxidation at a certain temperature. Crystal structure of Pd active species is another important factor to affect the catalytic activity besides chemical state. The pretreatment of inert atmosphere led to the change of crystal structure，with crystalline PdO transformed to amorphous state，and this change in crystal structure is beneficial for enhancing the catalytic activity.

Key words: Pd/γ-Al2O3, benzene, catalytic degradation, chemical state, crystal structure