Structural Transformation-Involved Synthesis of Nanosized ERI-Type Zeolite and Its Catalytic Property in the MTO Reaction

摘要

Nanosized ERI-type aluminophosphate was prepared by the calcination of a precursor material (denoted as ECNU-38P) synthesized using 1,1,6,6-tetramethyl-1,6-diazacyclododecane-1,6-diium hydroxide (TDDH) as a structure-directing agent. Thestructure of ECNU-38P is related to ERI topology but exhibits a highly disordered manner and contains both four- and six-coordinated Al atoms.In situXRD patterns revealed a rarely reported temperature-induced three-dimensional (3D)-to-3D structuraltransformation from ECNU-38P to the ordered ERI-type ECNU-38 zeolite at 573-623 K. Nanosized ERI-typesilicoaluminophosphate Si-ECNU-38 was also obtained by introducing Si atoms into the synthetic system of ECNU-38P. Thecatalytic performance of ERI-type silicoaluminophosphates in the methanol-to-olefin (MTO) reaction was revealed to be highly related to the crystal sizes

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