Zn-modified ZSM-5 catalysts are widely used in alkane aromatization.Self-pillared ZSM-5 zeolites are ideal supports to anchor metals due to their high specific surface areas and abundant Si-OH defects,facilitating the...Zn-modified ZSM-5 catalysts are widely used in alkane aromatization.Self-pillared ZSM-5 zeolites are ideal supports to anchor metals due to their high specific surface areas and abundant Si-OH defects,facilitating the dispersion of metal precursors in the zeolite.In this work,with self-pillared ZSM-5 zeolite nanosheets as the support,Zn_(x)/SPZSM-5 catalysts were prepared by the incipient wet impregnation method,and the evolution in structure,acidity,and Zn species distribution was studied.Their catalytic performance for n-octane aromatization was also evaluated.NH_(3)-temperature-programmed desorption,pyridine adsorption infrared spectra,X-ray photoelectron spectroscopy,and X-ray absorption spectroscopy results indicated that[ZnOH]^(+)species are formed by introducing zinc into ZSM-5 zeolite,at the expense of the silanol hydroxyl and proton acid sites.The distribution of acid sites,the nature of zinc species,and the subsequent catalytic performance of Zn_(x)/SPZSM-5 catalysts in n-octane aromatization are significantly influenced by the zinc contents.A linear correlation exists between the amount of[ZnOH]^(x)species and the selectivity of aromatics for n-octane aromatization over the Zn_(x)/SPZSM-5 catalysts.This could be attributed to the[ZnOH]^(x)species being a critical species for promoting BTX(benzene,toluene,and xylene)formation,which can enhance the alkanes dehydrogenation and olefins aromatization,thus improving BTX selectivity.展开更多
基金supported by the Scientific Research Funding Project of Liaoning Province(2024-MS-110,LJKQZ20221476)the Guangxi Science and Technology Major Program(GUIKEAA24206022)+3 种基金the Joint Special Open Innovation Foundation of Liaoning Binhai Laboratory(LBLG-2024-03)the Liaoning Province International Science and Technology Cooperation Program Project(2024JH2/102100004)the Shenyang Young and Middle-aged Scientific and Technological Innovation Talents Support Plan(RC220357)the Postgraduate Education Reform Project of Liaoning Province(LNYJG2022400)。
文摘Zn-modified ZSM-5 catalysts are widely used in alkane aromatization.Self-pillared ZSM-5 zeolites are ideal supports to anchor metals due to their high specific surface areas and abundant Si-OH defects,facilitating the dispersion of metal precursors in the zeolite.In this work,with self-pillared ZSM-5 zeolite nanosheets as the support,Zn_(x)/SPZSM-5 catalysts were prepared by the incipient wet impregnation method,and the evolution in structure,acidity,and Zn species distribution was studied.Their catalytic performance for n-octane aromatization was also evaluated.NH_(3)-temperature-programmed desorption,pyridine adsorption infrared spectra,X-ray photoelectron spectroscopy,and X-ray absorption spectroscopy results indicated that[ZnOH]^(+)species are formed by introducing zinc into ZSM-5 zeolite,at the expense of the silanol hydroxyl and proton acid sites.The distribution of acid sites,the nature of zinc species,and the subsequent catalytic performance of Zn_(x)/SPZSM-5 catalysts in n-octane aromatization are significantly influenced by the zinc contents.A linear correlation exists between the amount of[ZnOH]^(x)species and the selectivity of aromatics for n-octane aromatization over the Zn_(x)/SPZSM-5 catalysts.This could be attributed to the[ZnOH]^(x)species being a critical species for promoting BTX(benzene,toluene,and xylene)formation,which can enhance the alkanes dehydrogenation and olefins aromatization,thus improving BTX selectivity.
