3D Zeolite Research Articles

Two-Dimensional Zeolite Materials: Structural and Acidity Properties.

Zeolites are generally defined as three-dimensional (3D) crystalline microporous aluminosilicates in which silicon (Si4+) and aluminum (Al3+) are coordinated tetrahedrally with oxygen to form large negative lattices and consequent Brønsted acidity. Two-dimensional (2D) zeolite nanosheets with single-unit-cell or near single-unit-cell thickness (~2–3 nm) represent an emerging type of zeolite material. The extremely thin slices of crystals in 2D zeolites produce high external surface areas (up to 50% of total surface area compared to ~2% in micron-sized 3D zeolite) and expose most of their active sites on external surfaces, enabling beneficial effects for the adsorption and reaction performance for processing bulky molecules. This review summarizes the structural properties of 2D layered precursors and 2D zeolite derivatives, as well as the acidity properties of 2D zeolite derivative structures, especially in connection to their 3D conventional zeolite analogues’ structural and compositional properties. The timeline of the synthesis and recognition of 2D zeolites, as well as the structure and composition properties of each 2D zeolite, are discussed initially. The qualitative and quantitative measurements on the acid site type, strength, and accessibility of 2D zeolites are then presented. Future research and development directions to advance understanding of 2D zeolite materials are also discussed.

Enhanced Surface Activity of MWW Zeolite Nanosheets Prepared via a One-Step Synthesis.

The synthesis of two-dimensional (2D) zeolites has garnered attention due to their superior properties for applications that span catalysis to selective separations. Prior studies of 2D zeolite catalysts demonstrated enhanced mass transport for improved catalyst lifetime and selectivity. Moreover, the significantly higher external surface area of 2D materials allows for reactions of bulky molecules too large to access interior pores. There are relatively few protocols for preparing 2D materials, owing to the difficultly of capping growth in one direction to only a few unit cells. To accomplish this, it is often necessary to employ complex, commercially unavailable organic structure-directing agents (OSDAs) prepared via multistep synthesis. However, a small subset of zeolite structures exist as naturally layered materials where postsynthesis steps can be used to exfoliate samples and produce ultrathin 2D nanosheets. In this study, we selected a common layered zeolite, the MWW framework, to explore methods of preparing 2D nanosheets via one-pot synthesis in the absence of complex organic templates. Using a combination of high-resolution microscopy and spectroscopy, we show that 2D MMW-type layers with an average thickness of 3.5 nm (ca. 1.5 unit cells) can be generated using the surfactant cetyltrimethylammonium (CTA), which operates as a dual OSDA and exfoliating agent to affect Al siting and to eliminate the need for postsynthesis exfoliation, respectively. We tested these 2D catalysts using a model reaction that assesses external (surface) Brønsted acid sites and observed a marked increase in the conversion relative to three-dimensional MWW (MCM-22) and 2D layers prepared from postsynthesis exfoliation (ITQ-2). Collectively, our findings identify a facile and effective route to directly synthesize 2D MWW-type materials, which may prove to be more broadly applicable to other layered zeolites.

Molecule design of effective C2H4/C2H6 separation membranes: From 2D nanoporous graphene to 3D AHT zeolite

It is of great importance and challenge to explore effective membranes with optimal pore structures from diverse porous materials to replace energy-intensive cryogenic distillation processes for C2H4/C2H6 separation because of their similar physical properties. In this work, we proposed a strategy to screen the ideal 3D zeolite membrane by matching the zeolite structure to the designed 2D nanopore. Here, we found out the ideal AHT zeolite membrane with elliptical windows similar to the designed graphene-embedded 22-crown-8 ether pore with ultrahigh selectivity of C2H4/C2H6 mixtures via molecular dynamics simulations. The results demonstrate that the AHT zeolite membrane only allows the transport of C2H4 based on molecular size exclusion, which is validated by density functional theory calculations. Furthermore, the permeation performance studies of pure components demonstrate that the AHT zeolite membrane exhibits a C2H4/C2H6 selectivity of around 100 and a C2H4 permeability of 958 Barrer, superior to most of reported membrane materials.

Synthesis and characterization of a layered aluminosilicate NUD-11 and its transformation to a 3D stable zeolite.

Aluminosilicate zeolites are a well-known class of crystalline materials that have wide applications in various industrial fields due to their selective adsorption, acidic sites, and stable hydrothermal stability. Great efforts have been devoted to discovering new zeolite structures. As one of the effective methods, layered silicates have been used as precursors to produce stable zeolites through topotactic transformation. Herein, a new layered aluminosilicate, named NUD-11, was hydrothermally synthesized using N,N-dimethylbenzimidazolium as the structure directing agent (SDA). It was then converted into a stable crystalline zeolite by linking the interlayer Si-OH groups with a silylation agent, diethoxymethylsilane. Studies showed that the resulting NUD-11S consisted of alkylsilicate -O-Si(CH3)2-O- linkages between the adjacent layers to form interconnecting 10- and 12-membered ring channels. The calcined NUD-11S possessed micropores of 0.74 nm and 1.2 nm in diameter with a large specific surface area of 314 m2 g-1. The abundant microporosity would make NUD-11S useful as adsorbents or catalysts.

Guaiacol hydrodeoxygenation over Ni2P supported on 2D-zeolites

Abstract Different 2D zeolites, namely lamellar ZSM-5 (L-ZSM-5), the corresponding silica pillared ZSM-5 (PI-ZSM-5) and an MCM-22 sample, were investigated as nickel phosphide supports and evaluated as catalysts for guaiacol hydrodeoxygenation (HDO). Characterization confirmed that all loaded materials preserved a high crystallinity degree with formation of the Ni2P phase. The incorporation of Ni2P reduced adsorption capacity, affecting differently the micro- or mesoporous systems, depending on the zeolitic support. Ni2P deposition also modified the acidic properties of the zeolites due to the generation of new acid sites of moderate strength attributed to both Niδ+ species (Lewis acid sites) and the presence of residual P−OH moieties (weak Bronsted acid sites). The catalysts were tested in the HDO of guaiacol at 220 and 260 °C and 40 bar of H2. In all cases, ZSM-5 based catalysts exhibited higher conversions and HDO efficiencies than Ni2P/MCM-22, which denotes that MFI zeolitic structure favors the deoxygenation of phenolic compounds, yielding cyclohexane as major reaction product. This excellent catalytic performance is attributed to the combination of high surface area and optimal acidic properties since a synergetic effect was achieved between the acid sites of the raw zeolitic support and those provided by nickel phosphide having an enhanced accessibility. Thus, the best HDO performance was obtained over Ni2P supported on the pillared ZSM-5, showing a 78 % of guaiacol conversion and 95 % of selectivity towards deoxygenated molecules.

Quantification of Lewis acid sites in 3D and 2D TS-1 zeolites: FTIR spectroscopic study

Abstract Titanium silicalite 1 (TS-1) zeolite is an important selective oxidation catalyst. Recently prepared layered and pillared forms expanded the application of TS-1 to the catalytic oxidation of bulky molecules. Despite progress in designing and application of titanosilicate zeolites in catalysis, only qualitative information of their acidity is available. Herein, we report thorough characterization of acid sites in TS-1 zeolites of different morphologies (3D TS-1, layered 2D TS-1, 2D TS-1 pillared either with silica (TS-1-PISi) or silica-titania (TS-1-PITi)) using FTIR spectroscopy and probe molecules. FTIR of adsorbed pyridine was used for quantification of Ti-associated Lewis acid sites based on the integral intensity of υ8a absorption band ca. 1608 cm−1 and measured integrated molar extinction coefficient (e1608(Ti-LAS) = 0.71 ± 0.01 cm μmol–1). Thermodesorption of pyridine monitored with FTIR showed that distribution of strength of Lewis acid sites is, to some extent, dependent on the way of Ti incorporation in the samples. TS-1-PITi, containing large fraction of external surface Ti(OH)(OSi)3 species introduced post-synthesis, showed increased concentration of stronger Lewis acid centres. FTIR spectroscopy of TS-1 with pre-adsorbed quinoline and d3-acetonitrile probe confirmed enhanced relative concentration of external Lewis acid sites in all layered TS-1 materials (28–38%) vs. 3D TS-1 (2%).

Solvation effect on binding modes of model lignin dimer compounds on MWW 2D-zeolite.

Lignin as a potential renewable source of biofuels, chemicals, and other value-added products has gained much attention. However, the complexity of lignin structure poses a significant challenge for developing efficient valorization techniques. As most processes involve solvothermal conditions to minimize energy cost, lignin depolymerization is governed by reaction conditions (temperature and pressure) and solvents. In this work, binding of β-O-4 linkage consisting lignin dimers on MWW two-dimensional (2D) zeolite is investigated using periodic density functional theory. Furthermore, the effect of different terminated surfaces (H:OH% = 100:0; 50:50; 0:100%), different temperatures (323, 353, 373 K), and different solvents (water and methanol) on the binding modes is quantified. Our work shows that in the gas phase the binding strength increases 10-15 kcal/mol upon increasing the number of hydroxyl groups on the surface. Also, the phenolic dimer binds more strongly than the nonphenolic dimer, and the binding strength of model compounds increases in the presence of the solvent. Analysis of structural changes in the presence of the solvent reveals that the aromatic rings are parallel to the zeolite surface and primary interaction with zeolite is through the hydroxyl groups near the β-O-4 linkage. Furthermore, while the solvation energy decreases with increasing temperature, the opposite trend is observed for the binding energy with the surface.

Bridging the Gap between Structurally Distinct 2D Lamellar Zeolitic Precursors through a 3D Germanosilicate Intermediate.

There is broad scientific interest in lamellar zeolitic materials for a large variety of technological applications. The traditional synthetic methods towards two-dimensional (2D) zeolitic precursors have made a great impact in the construction of families of related zeolites; however, the connection between structurally distinct 2D zeolitic precursors is much less investigated in comparison, thereby resulting in a synthetic obstacle that theoretically limits the types of zeolites that can be constructed from each layer. Herein, we report a Ge-recycling strategy for the topotactic conversion between different 2D zeolitic precursors through a three-dimensional (3D) germanosilicate. Specifically, the intermediate germanosilicate can be constructed within 150 min by taking advantage of its structural similarity with the parent lamellar precursor. This process enables the conversion of one 2D zeolite structure into another distinct structure, thus overcoming the synthetic obstacle between two families of zeolitic materials.

Effect of Si/Al Ratio on the Catalytic Activity of Two‐Dimensional MFI Nanosheets in Aromatic Alkylation and Alcohol Etherification

AbstractZeolite catalysts with pronounced two‐dimensional (2D) morphologies, specifically 2D MFI nanosheets composed of multilamellar stacks of MFI nanosheets, are hypothesized to offer accessibility advantages in catalytic reactions involving large, bulky molecules. The Si/Al ratio of zeolite catalysts is an important parameter determining their performance. However, the effect of Si/Al ratio on catalytic reactivity is not well understood in 2D zeolite catalysts. To provide further insight into this issue, the catalytic performance of 2D MFI nanosheet materials with different Si/Al ratios is compared using the liquid phase Friedel‐Crafts alkylation of mesitylene with benzyl alcohol & the self‐etherification of benzyl alcohol that occurs in parallel, both of which are catalyzed by Brønsted acid sites. The turnover frequency (TOF) of the catalysts is found to decrease with decreasing Si/Al ratio, with the etherification reaction being the main contributor to this trend. When the same reaction is carried out in the presence of a bulky poison, 2,6 di‐tert‐butylpyridine (DTBP), to selectively deactivate the external acid sites, only the etherification reaction of benzyl alcohol takes place in the micropores of the 2D MFI catalyst and the effectiveness factor is found to decrease with decreasing Si/Al ratio. The single component adsorption isotherms of benzyl alcohol show that the uptake normalized per acid site decreases with decreasing Si/Al ratio. Thus, increasing the density of acid sites in the micropores by decreasing the Si/Al ratio makes it more difficult for the reactant molecules to access them, as demonstrated by the decrease in TOF and the effectiveness factor. While the micropore reactions (benzene alkylation, alcohol etherification) showed a clear trend with Si/Al ratio, the reaction catalyzed on the external surface (mesitylene alkylation) did not, showing distinct differences in reactivity.

Synthesis and structure determination of SCM-15: a 3D large-pore zeolite with interconnected straight 12×12×10-ring channels

A new germanosilicate zeolite named SCM-15 (Sinopec Composite Material No. 15), the first zeolite containing a 3-dimensional (3D) channel system with interconnected 12-, 12-, and 10-ring channels (pore sizes: 6.1×7.2, 6.1×7.4, and 5.2×5.9 A), has been synthesized using neutral 4-pyrrolidinopyridine as organic structure-directing agents (OSDAs). Its structure has been determined by combining single-crystal electron diffraction (SCED) and synchrotron powder X-ray diffraction (SPXD) data. The unique open framework structure of SCM-15 is related to that of FOS-5 (BEC), ITQ-7 (ISV), PKU-16 (POS), ITQ-26 (IWS), ITQ-21, Beta polymorph B, and SU-78B, since all these framework structures can be constructed from similar chains which are connected through shared 4-ring or double 4-ring (d4r) units. Based on this relation, six topologically reasonable 3D large or extra-large pore hypothetical zeolites are predicted.

Environmental TEM Studies Reveal Catalyst/Support Registry on 2D Zeolites

Journal Article Environmental TEM Studies Reveal Catalyst/Support Registry on 2D Zeolites Get access Jennifer Carpena-Núñez, Jennifer Carpena-Núñez Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, OH 45433Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973 Corresponding author: jennifer.carpena.ctr@us.af.mil Search for other works by this author on: Oxford Academic Google Scholar Dmitri Zakharov, Dmitri Zakharov Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973 Search for other works by this author on: Oxford Academic Google Scholar Rahul Rao, Rahul Rao Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, OH 45433UES, Inc., Dayton, OH 45431 Search for other works by this author on: Oxford Academic Google Scholar Donghun Kim, Donghun Kim Department of Chemical Engineering, University of Minnesota, Minneapolis, MN 55455 Search for other works by this author on: Oxford Academic Google Scholar J Anibal Boscoboinik, J Anibal Boscoboinik Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973 Search for other works by this author on: Oxford Academic Google Scholar Eric A Stach, Eric A Stach Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104 Search for other works by this author on: Oxford Academic Google Scholar Michael Tsapatsis, Michael Tsapatsis Department of Chemical and Biomolecular Engineering, John Hopkins University, Baltimore, MA 21218 Search for other works by this author on: Oxford Academic Google Scholar Dario Stacchiola, Dario Stacchiola Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973 Search for other works by this author on: Oxford Academic Google Scholar Benji Maruyama Benji Maruyama Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, OH 45433 Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 25, Issue S2, 1 August 2019, Pages 1458–1459, https://doi.org/10.1017/S143192761900802X Published: 01 August 2019

Fabricating Mechanically Robust Binder-Free Structured Zeolites by 3D Printing Coupled with Zeolite Soldering: A Superior Configuration for CO2 Capture.

3D‐printing technology is a promising approach for rapidly and precisely manufacturing zeolite adsorbents with desirable configurations. However, the trade‐off among mechanical stability, adsorption capacity, and diffusion kinetics remains an elusive challenge for the practical application of 3D‐printed zeolites. Herein, a facile “3D printing and zeolite soldering” strategy is developed to construct mechanically robust binder‐free zeolite monoliths (ZM‐BF) with hierarchical structures, which can act as a superior configuration for CO2 capture. Halloysite nanotubes are employed as printing ink additives, which serve as both reinforcing materials and precursor materials for integrating ZM‐BF by ultrastrong interfacial “zeolite‐bonds” subjected to hydrothermal treatment. ZM‐BF exhibits outstanding mechanical properties with robust compressive strength up to 5.24 MPa, higher than most of the reported structured zeolites with binders. The equilibrium CO2 uptake of ZM‐BF reaches up to 5.58 mmol g−1 (298 K, 1 bar), which is the highest among all reported 3D‐printed CO2 adsorbents. Strikingly, the dynamic adsorption breakthrough tests demonstrate the superiority of ZM‐BF over commercial benchmark zeolites for flue gas purification and natural gas and biogas upgrading. This work introduces a facile strategy for designing and fabricating high‐performance hierarchically structured zeolite adsorbents and even catalysts for practical applications.

Phase Transformation Behavior of a Two-Dimensional Zeolite.

Understanding the molecular-level mechanisms of phase transformation in solids is of fundamental interest for functional materials such as zeolites. Two-dimensional (2D) zeolites, when used as shape-selective catalysts, can offer improved access to the catalytically active sites and a shortened diffusion length in comparison with their 3D analogues. However, few materials are known to maintain both their intralayer microporosity and structure during calcination for organic structure-directing agent (SDA) removal. Herein we report that PST-9, a new 2D zeolite which has been synthesized via the multiple inorganic cation approach and fulfills the requirements for true layered zeolites, can be transformed into the small-pore zeolite EU-12 under its crystallization conditions through the single-layer folding process, but not through the traditional dissolution/recrystallization route. We also show that zeolite crystal growth pathway can differ according to the type of organic SDAs employed.

Phase Transformation Behavior of a Two‐Dimensional Zeolite

AbstractUnderstanding the molecular‐level mechanisms of phase transformation in solids is of fundamental interest for functional materials such as zeolites. Two‐dimensional (2D) zeolites, when used as shape‐selective catalysts, can offer improved access to the catalytically active sites and a shortened diffusion length in comparison with their 3D analogues. However, few materials are known to maintain both their intralayer microporosity and structure during calcination for organic structure‐directing agent (SDA) removal. Herein we report that PST‐9, a new 2D zeolite which has been synthesized via the multiple inorganic cation approach and fulfills the requirements for true layered zeolites, can be transformed into the small‐pore zeolite EU‐12 under its crystallization conditions through the single‐layer folding process, but not through the traditional dissolution/recrystallization route. We also show that zeolite crystal growth pathway can differ according to the type of organic SDAs employed.

Vapor-Phase Strategy to Pillaring of Two-Dimensional Zeolite.

Two-dimensional (2D) layered zeolites are new forms of 3D zeolite frameworks. They can be pillared to form more open porous structures with increased access for reactants that are too big for the micropores of zeolites. The current pillaring procedure, however, requires intercalation of pillaring precursors by dispersing 2D zeolite in an alkoxide liquid and hydrolizing entrapped alkoxide to form inorganic oxide pillars in an aqueous alkaline solution. Both steps use excess solvents, generate significant waste, and require multiple synthesis and separation steps. Here we report a vapor-phase pillarization (VPP) process to produce pillared zeolites from 2D layered zeolite structures. The VPP process has ∼100% efficiency of alkoxide usage in the intercalation step, requires less (and, in some cases, zero) water addition in the hydrolysis step, does not require separation for product recovery, and generates no liquid waste. Furthermore, synthesis of pillared zeolites via the VPP process can be accomplished within a single apparatus with one-time operation. The pillared zeolite prepared by the VPP method preserved the zeolitic layered structure as well as acidity and showed enhancement in catalytic alkylation of mesitylene with benzyl alcohol compared to 2D layered zeolite without pillarization treatment.

Continuous Zeolite MFI Membranes Fabricated from 2D MFI Nanosheets on Ceramic Hollow Fibers

AbstractHigh‐quality 2D MFI nanosheet coatings were prepared on α‐alumina hollow fiber supports by vacuum filtration and then transformed into molecular sieving membranes by two sequential hydrothermal treatments. This processing method eliminates the need for specially engineered silica‐based support materials that have so far been necessary to allow the formation of functional membranes from 2D MFI nanosheets. The sequential steps enhance adhesion of the membrane on the fiber support, fill in nanoscale gaps between the 2D nanosheets, and preserve the desirable (0k0) out‐of‐plane orientation without the need of any support engineering or modification. The membrane exhibits high performance for separation of n‐butane from i‐butane, and for other technologically important hydrocarbon separations. The present findings have strong implications on strategies for obtaining thin, highly selective zeolite membranes from 2D zeolites in a technologically scalable manner.

A study of the external and internal sites of 2D and 3D zeolites through the FTIR investigation of the adsorption of ammonia and pivalonitrile

In this work absorption coefficients of the 1450 cm−1 IR maximum of ammonium ions (formed by ammonia adsorbed on BAS) and the CN band assigned to pivalonitrile interacting with BAS, are determined for MWW zeolites (MCM-22, MCM-56 and UJM-1). These three distinct types of MWW zeolites, differing in layer arrangement but not the framework (intra-layer) topology, are used to show differences in the concentration of Brønsted acid sites that are available for pivalonitrile (BAS located at the external crystal surfaces). It is shown that in the case of ammonium ions, common absorption coefficient for 10-rings zeolites (MWW, MFI) may be used (ε(NH4+) = 0.090 cm2/μmol). For pivalonitrile interacting with Brønsted acid sites in MWW zeolites the value of absorption coefficient was determined (0.05 cm2/μmol) together with re-assignment of the IR bands of pivalonitrile adsorbed in MWW based on thorough analysis of the published and obtained here spectra. The revised assignment is expected to be applicable to other layered zeolites.

An Interrupted Zeolite PKU‐26 and Its Transformation to a Fully Four‐Connected Zeolite PKU‐27 upon Calcination

The thermal stability and structural transformation mechanism are critical for the industrial applications of zeolites and the design of new framework types. Herein, a new zeolite PKU-26 has been hydrothermally synthesized under fluoride conditions using a tetraethylammonium (TEA+ ) cation as the structure-directing agent (SDA) and its framework contains partial Q3 T atoms [Q3 for T(-O-T)3 OH]. Upon calcination, PKU-26 processed a single-crystal to single-crystal transformation to another novel zeolite PKU-27 with the elimination of terminal -OH groups and enhanced thermal stability up to 650 °C, exhibiting the first Q3 →Q4 transformation [Q4 for T(-O-T)4 ] in 3D zeolite frameworks. The mechanism of the structural transformation, involving proton transfer, framework dehydration, and TO4 reconstruction, is proposed and supported by theoretical calculations.

Encapsulation of Pt nanoparticles into IPC-2 and IPC-4 zeolites using the ADOR approach

Zeolites with encapsulated metal nanoparticles (NPs) attract much attention due to the catalytic activity, stability and shape-selective properties of such materials in heterogeneous catalysis. One of the methods for introduction of metal NPs into the zeolite system is based on use of two dimensional (2D) layered precursors that are loaded with Pt source and consecutively transformed to three dimensional (3D) zeolites. This method can be combined with recently developed approach for zeolite synthesis; the ADOR (Assembly, Disassembly, Organization, and Reassembly) approach that is based on the 3D-2D-3D transformation of zeolites. Here, we report a synthesis of two ADOR zeolites: IPC-2 (OKO topology) and IPC-4 (PCR topology) functionalized with Pt NPs, [email protected] and [email protected], respectively. [email protected] was prepared by intercalation of platinum(0)-2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetra siloxane into IPC-1P layered precursor and subsequent calcination. [email protected] zeolite was prepared by the swelling of IPC-1P with the mixture of surfactant and Pt source. Final materials were investigated by XRD, nitrogen sorption, ICP-OES, and electron microscopy (SEM and STEM). Structural and textural analysis confirmed the successful syntheses of two ADOR zeolites. The size and distribution of Pt NPs were investigated by STEM. The platinum content was 0.34 wt% and 0.32 wt% and the average size of Pt NPs of 0.98 nm and 0.96 nm for [email protected] and [email protected], respectively. [email protected] exhibited a broader range of Pt sizes due to larger pores.

Database of Computation-Ready 2D Zeolitic Slabs

Zeolites are nanoporous aluminosilicates widely used in catalysis and separations applications. Though generally formed as 3D crystals, new synthesis techniques have given access to 2D zeolite nanosheets with small diffusion path lengths and accelerated molecular diffusion. Since most previous research has focused on bulk zeolite crystals, there is little understanding of the surface adsorption and diffusion mechanisms likely involved at such length scales and their contributions to the permeability and selectivity of different species. To enable the systematic examination of such surface properties, we constructed a database of more than 800,000 computation-ready 2D zeolite nanosheets from the full range of known zeolite structures in the IZA database of zeolite structure types. The nanosheet surfaces cover a wide range of orientations and were created via the principle of minimizing the number of bonds broken during the termination of a unit cell. The database consists of two sets of nanosheets: one set...