Layer like porous materials with hierarchical structure

Abstract

Many chemical compositions produce layered solids consisting of extended sheets with thickness not greater than a few nanometers. The layers are weakly bonded together in a crystal and can be modified into various nanoarchitectures including porous hierarchical structures. Several classes of 2-dimensional (2D) materials have been extensively studied and developed because of their potential usefulness as catalysts and sorbents. They are discussed in this review with focus on clays, layered transition metal oxides, silicates, layered double hydroxides, metal(iv) phosphates and phosphonates, especially zirconium, and zeolites. Pillaring and delamination are the primary methods for structural modification and pore tailoring. The reported approaches are described and compared for the different classes of materials. The methods of characterization include identification by X-ray diffraction and microscopy, pore size analysis and activity assessment by IR spectroscopy and catalytic testing. The discovery of layered zeolites was a fundamental breakthrough that created unprecedented opportunities because of (i) inherent strong acid sites that make them very active catalytically, (ii) porosity through the layers and (iii) bridging of 2D and 3D structures. Approximately 16 different types of layered zeolite structures and modifications have been identified as distinct forms. It is also expected that many among the over 200 recognized zeolite frameworks can produce layered precursors. Additional advances enabled by 2D zeolites include synthesis of layered materials by design, hierarchical structures obtained by direct synthesis and top-down preparation of layered materials from 3D frameworks.

Facile synthesis of mesostructured ZSM-5 zeolite with enhanced mass transport and catalytic performances

“…Tsapatsis and co-workers have also reported one-step synthesis of self-pillared pentasil (SPP) zeolite composed of orthogonally connected single-unit cell lamellae [20]. Many other hierarchical zeolite materials possessing similar nanosheets structure reported recently [21][22][23][24].…”

Interlayer Nanoarchitectonics of Two‐Dimensional Transition‐Metal Dichalcogenides Nanosheets for Energy Storage and Conversion Applications

“…Comprehensive DFT calculations are helpful to understand the role of interlayer engineering, making it possible to quantitatively describing the dependence of material property on interlayer spacing and intercalated species. In short, interlayer engineering can be applied to a wide range of MX 2 and other layered materials (layered metal chalcogenides, layered transition metal oxides and layered Xenes) [156][157][158][159][160][161] as efficient host materials for storage of various foreign species. Interlayer engineering on these materials opens up new doors for developing novel intercalation chemistry and advanced materials for next-generation energy storage and conversion devices as well as environmental remediation.…”

New organic‐pillared zincophosphate and interpenetrating‐layered zinc coordination polymer: Crystal growth on tarbuttite‐like sheets with surface‐active carboxylic acid groups

“…Layered zeolitic materials have drawn a great research interest since they play a role as a precursor to generate not only known 3D zeolite frameworks by calcination but also other types of structures by swelling, pillaring, or exfoliating . The exposed silanol groups on the surface of those layered zeolites stand as an effective attaching point for functionalization including immobilization of enzymes and multifunctional catalyst.…”