Ordered End-Member of ZSM-48 Zeolite Family

• Published in: Chemistry of materials 2009-01, Vol.21 (2), p.371-380
• Main Authors: Kirschhock, C. E. A, Liang, D, Tendeloo, G. Van, Fécant, A, Hastoye, G, Vanbutsele, G, Bats, N, Guillon, E, Martens, J. A
• Format: Article
• Language: English
• Subjects: Catalysis and Catalysts; Characterization of Materials; Crystal Growth
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm802614x

ZSM-48 and related zeolites are considered to be highly disordered structures. Different polytypes can be clearly distinguished by simulation of high-resolution electron microscopy images. Synthesis of phase-pure polytypes was attempted. One of the investigated samples crystallized via seeding designated as COK-8 consisted of nanoscopic, needlelike crystals with a very large length/width ratio, growing along the pore direction. These specimens are phase-pure polytype 6 (PT6, numbering according to Lobo and van Koningsveld). Aggregates of these nanoneedles occasionally contained a second polytype: PT1. The latter polytype occurred more abundantly in larger crystal rods in an IZM-1 sample crystallized in ethylene glycol. Here too, the isolated crystallites mainly consist of large, defect-free regions of PT6. A simulation of polytype lattice energies offers a rational explanation for the observed polytypical intergrowth formation.