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Hierarchical cross-like SAPO-34 catalysts with different pore size distributions were obtained via hydrothermal synthesis with polyethylene glycol(PEG) as the mesopore-generating agent.The hierarchical SAPO-34 molecular sieves were characterized using X-ray diffraction,scanning electron microscopy,N_2adsorption-desorption,thermogravimetric analysis,and temperature-programmed NH_3 desorption.The cross-like SAPO-34 catalysts exhibited enriched multi-porosity,and the sizes of their mesopores ranged from 10 to 50 nm.Both the mesoporous structures and morphologies of the hierarchical SAPO-34 could be further tuned through adjustments of the amount of PEG used.The as-obtained SAPO-34 showed dramatic catalytic performance in the conversion of dimethyl ether into olefins.A maximum selectivity of olefins of 96%was achieved,which was attributed to the rapid transport of the reactants and products in zeolitic micropores through mesopores.
Hierarchical cross-like SAPO-34 catalysts with different pore size distributions were obtained via hydrothermal synthesis with polyethylene glycol (PEG) as the mesopore-generating agent. Hierarchical SAPO-34 molecular sieves were characterized by X-ray diffraction, scanning electron microscopy, N_2adsorption-desorption, thermogravimetric analysis, and temperature-programmed NH_3 desorption.The cross-like SAPO-34 samples exhibited enriched multi-porosity, and the sizes of their mesopores ranged from 10 to 50 nm.Both the mesoporous structures and morphologies of the hierarchical SAPO-34 could be further tuned through the adjustment of the amount of PEG used. As a-SAPO-34 showed dramatic catalytic performance in the conversion of dimethyl ether into olefins. A maximum selectivity of olefins of 96% was achieved, which was attributed to the rapid transport of the reactants and products in zeolitic micropores through mesopores.