Decoupling nucleation from crystal-growth for the synthesis of nanocrystalline zeolites. Issue 21 (19th May 2020)

• Record Type: Journal Article
• Authors: Zhang, Guanqun; Fan, Yaqi; Huang, Ju; Wang, Lijin; Yang, Chengguang; Lyu, Meng; Liu, Haiming; Ma, Yanhang
• Is Part Of: Dalton transactions. Volume 49:Issue 21(2020)
• Page Start: 7258
• Page End: 7266
• Publication Date: 2020-05-19
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d0dt01291b
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : A facile synthesis strategy for nanosized zeolites by successfully decoupling nucleation from crystal-growth in a concentrated hydrated gel (HG) system. Abstract : The increasing demands for catalysts with improved accessibility to reactants call for a rational synthesis of nanosized zeolites. Herein we developed a facile approach for highly crystalline MFI-type (Silicalite-1 and ZSM-5) and beta zeolites with variable Si/Al ratios and high yield. This was achieved by kinetically decoupling the nucleation from the growth process of the zeolites in a highly concentrated gel system via a temperature-staged treatment. The carefully controlled low-water environment ensures only nucleation in stage I (aging), and hence the generation of abundant nuclei for the subsequent rapid crystallization within a self-confined space at stage II (growth). The method, without using expensive templates or additives, allows the syntheses of nanosized, well-isolated ZSM-5 (Si/Al = 100–∞, 36–88 nm, yield >85%) and Beta (Si/Al = 25–100, 21–66 nm, yield >95%). The ultra-small crystal size endows ZSM-5 zeolites with good catalytic activity, product selectivity and remarkably longer lifetime in methanol conversion reactions.