Abstract:

HZSM-5 catalysts were modified by the addition of Zn through impregnation and hydrothermal methods respectively. X ray diffraction（XRD），X ray photoelectron spectroscopy（XPS），nitrogen adsorption，temperature-programmed desorption of ammonia（NH₃-TPD）and scanning electron microscopy（SEM）techniques were used to characterize the catalysts. The results showed that the addition of Zn by the two methods had little influence on the skeletal structure，pore structure and morphology of catalyst particles，but could change the surface acidity of catalysts. The addition of Zn by the two methods could lead to a reduction of the amounts of strong acid sites apparently，causing an increase of the amounts of weak acid sites slightly. In addition，the catalytic performance of catalysts for the aromatization of methanol were studied. The initial catalytic properties and selectivities of aromatization products over the HZSM-5 modified by Zn through the two methods were superior to those of HZSM-5. But the addition of Zn could lead to carbon deposition on the surface of HZSM-5 catalyst and result in quick deactivation.