Structure and catalytic properties of the most complex intergrown zeolite ITQ-39 determined by electron crystallography

Abstract

Porous materials such as zeolites contain well-defined pores in molecular dimensions and have important industrial applications in catalysis, sorption and separation. Aluminosilicates with intersecting 10- and 12-ring channels are particularly interesting as selective catalysts. Many porous materials, especially zeolites, form only nanosized powders and some are intergrowths of different structures, making structure determination very challenging. Here, we report the atomic structures of an aluminosilicate zeolite family, ITQ-39, solved from nanocrystals only a few unit cells in size by electron crystallography. ITQ-39 is an intergrowth of three different polymorphs, built from the same layer but with different stacking sequences. ITQ-39 contains stacking faults and twinning with nano-sized domains, being the most complex zeolite ever solved. The unique structure of ITQ-39, with a three-dimensional intersecting pairwise 12-ring and 10-ring pore system, makes it a promising catalyst for converting naphtha into diesel fuel, a process of emerging interest for the petrochemical industry.

3D Transition Metal Ordering and Rietveld Stacking Fault Quantification in the New Oxychalcogenides La2O2Cu2–4xCd2xSe2

“…Stacking fault Rietveld refinement will allow the accurate cation distributions, detailed structural information and quantitative analysis of inoperando systems needed for full understanding of their chemistry. Similar faulting precludes detailed structural studies of a range of important zeolites [37][38][39][40][41][42][43][44] . Other areas likely to benefit include materials with low temperature topotactic transformations 77 , intercalation/ion-exchange hosts, a variety of layered minerals 78 , and understanding the details and implications of hexagonal/cubic intergrowths in different forms of ice 50,51 .…”

“…29 Examples include a wide range of battery materials [30][31][32][33][34][35][36] , zeolites [37][38][39][40][41][42][43][44] , metals 45,46 , clays 47,48 , diamond 49,50 , ice 50, 51 , nitrides [52][53][54] , carbides [55][56][57] , catalysts 58 , layered hydroxides and other intercalation/ion-exchange hosts [59][60][61][62] . The Rietveld method we describe will be applicable to all these systems and will allow detailed and precise information to be obtained on the structure of individual phases and quantification of phase mixtures and their evolution in operando.…”

Lightweight nanoporous metal hydroxide-rich zeotypes

“…T he discovery of new inorganic framework materials that exhibit microporosity is an important synthesis target as has been recently highlighted [1][2][3][4][5][6][7] . The widespread industrial use of zeolites and zeotypes in areas as diverse as catalysis, gas separation and storage, ion exchange and as desiccants requires the design and control of structural and chemical properties such as pore size and interconnectivity, thermal stability, surface site acidity, chirality and, for gas storage, weight.…”

“…A comprehensive investigation of beryllium-arsenate and beryllium-phosphate framework chemistry was undertaken using a variety of amine templates to induce nanoporous structure formation. Overall 3 respectively. Beryllium and phosphorus/arsenic are distributed over the T-atom sites with individual site Be:P/As ratios ranging from near 1.0:0.0 to 0.5:0.5 producing overall ratios of 3( ± 0.3):1 (BET-P) and 2.5( ± 0.15):1 (BET-As).…”

Synthesis of an extra-large molecular sieve using proton sponges as organic structure-directing agents

“…Crystals considered as powder by X-ray diffraction behave as single crystals by electron diffraction. Recently, we developed a method known as rotation electron diffraction (RED) for collecting 3D electron diffraction data by combining electron beam tilt and goniometer tilt on a transmission electron microscope (TEM) (36). This method is promising for both phase identification and structure determination of unknown micro-and nano-sized crystals.…”