Preparation of Cu-based Hierarchical Pore ZSM-5 Zeolite Single Crystals and Their Catalytic Properties for Nitrobenzene Hydrogenation

In order to solve the problem of irreversible damage of zeolite framework in the process of intracrystalline hierarchically porous creation，a single crystal of silica-alumina zeolite ZSM-5（OMMS-ZSM-5）with hierarchically ordered macro-meso-microporous structure was successfully bottom-up in situ synthesized by using ordered macromesomicroporous carbon with anti-opal structure as a hard template，which possesses high external specific surface area（195.8 m2/g）and pore volume（0.27 cm3/g）. In addition，a series of Cu-OMMS-ZSM-5 catalysts with different Cu loadings（mass fraction：1%，5%，10%）was prepared by impregnation method using OMMS-ZSM-5 as a carrier to investigate the catalytic ability of different metal loading catalysts in the liquid-phase hydrogenation reaction of nitro⁃ benzene. The physical and chemical properties of the prepared catalysts were comprehensively characterized by SEM，TEM，XRD，NMR，N2adsorption-desorption，NH3-TPD，XPS and H2-TPR tests，which shows that the Cu elements are highly dispersed in the form of CuO，and the conversion of nitrobenzene reaches up to 96.8% and the selectivity of aniline reaches 99.3% when the loading is 9.58%（mass fraction）. Compared with the Cu-based micron ZSM-5 zeolite catalytic material，the aniline selectivity and the nitrobenzene conversion of Cu-OMMS-ZSM-5 are improved by 32.4% and 26.1%，respectively，and the high catalytic activity is maintained after three cycles.