Submit to Molecules Review for Molecules Propose a Special Issue

Journal Menu

Journal Browser

► Journal Browser

Porous Materials: Synthetic Strategies and Applications

Special Issue Editors
Special Issue Information
Published Papers

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Inorganic Chemistry".

Deadline for manuscript submissions: closed (31 January 2024) | Viewed by 8069

Share This Special Issue

Special Issue Editors

Dr. Mei Hong

E-Mail Website
Guest Editor

Guangdong Provincial Key Lab of Nano-Micro Materials Research School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
Interests: porous materials; synthesis; applications

Dr. Guangchao Zheng

E-Mail Website
Guest Editor

School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450001, China
Interests: applications-oriented synthesis of nanomaterials (Nobel metal nanoparticles and metal-organic frameworks); photocatalysis; surface-enhanced Raman scattering; chiral nanophotonics

Special Issue Information

Dear Colleagues,

Porous materials possess cavities, channels, or interstices, into which guest molecules can be selectively adsorbed, transiently stored, and chemically transformed. Numerous porous materials have been developed and investigated, such as zeolites, metal–organic frameworks, carbon-based materials, polymer-based materials, and inorganic–organic hybrids, exhibiting distinct advantages in a vast number of fields, including the chemical industry, energy, and environmental protection.

This Special Issue, entitled "Porous Material Synthetic Strategies and Applications", aims to provide updates on recent advances in the synthesis methods, characterization, performance, and applications of porous materials. Submissions to this Special Issue are welcome in the form of original research papers or short reviews, and contributions are expected to include the function-led design, controlled fabrication methods, novel structural analyses, and novel applications of porous materials.

Dr. Mei Hong
Dr. Guangchao Zheng
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (5 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Research

15 pages, 5711 KiB

Open AccessArticle

Spherical Binderless 4A/5A Zeolite Assemblies: Synthesis, Characterization, and Adsorbent Applications

by Tong Li, Shuangwei Wang, Jinqiang Gao, Ruiqiang Wang, Guifeng Gao, Guangming Ren, Shengnan Na, Mei Hong and Shihe Yang

Molecules 2024, 29(7), 1432; https://doi.org/10.3390/molecules29071432 - 22 Mar 2024

Viewed by 420

Abstract

Zeolite microspheres have been successfully applied in commercial-scale separators such as oxygen concentrators. However, further enhancement of their applications is hampered by the post-synthetic shaping process that formulates the zeolite powder into packing-sized spherical bodies with various binders leading to active site blockage and suboptimal performance. Herein, binderless zeolite microspheres with a tunable broad size range from 2 µm to 500 µm have been developed with high crystallinity, sphericity over 92%, monodispersity with a coefficient of variation (CV) less than 5%, and hierarchical pore architecture. Combining precursor impregnation and steam-assisted crystallization (SAC), mesoporous silica microspheres with a wide size range could be successfully transformed into zeolite. For preserved size and spherical morphology, a judicious selection of the synthesis conditions is crucial to ensure a pure phase, high crystallinity, and hierarchical architecture. For the sub-2-µm zeolite microsphere, low-temperature prolonged aging was important so as to suppress external zeolization that led to a large, single macroporous crystal. For the large 500 µm sphere, ultrasound pretreatment and vacuum impregnation were crucial and facilitated spatially uniform gel matrix dispersion and homogenous crystallization. The obtained zeolite 5A microspheres exhibited excellent air separation performance, while the 4A microspheres displayed ammonium removal capabilities. This work provides a general strategy to overcome the existing limitations in fabricating binder-free technical bodies of zeolites for various applications. Full article

(This article belongs to the Special Issue Porous Materials: Synthetic Strategies and Applications)

► Show Figures

Graphical abstract

22 pages, 4410 KiB

Open AccessArticle

Enhanced Solid-State Fluorescence of Flavin Derivatives by Incorporation in the Metal-Organic Frameworks MIL-53(Al) and MOF-5

by Dietrich Püschel, Simon Hédé, Iván Maisuls, Simon-Patrick Höfert, Dennis Woschko, Ralf Kühnemuth, Suren Felekyan, Claus A. M. Seidel, Constantin Czekelius, Oliver Weingart, Cristian A. Strassert and Christoph Janiak

Molecules 2023, 28(6), 2877; https://doi.org/10.3390/molecules28062877 - 22 Mar 2023

Cited by 2 | Viewed by 2010

Abstract

The flavin derivatives 10-methyl-isoalloxazine (MIA) and 6-fluoro-10-methyl-isoalloxazine (6F-MIA) were incorporated in two alternative metal-organic frameworks, (MOFs) MIL-53(Al) and MOF-5. We used a post-synthetic, diffusion-based incorporation into microcrystalline MIL-53 powders with one-dimensional (1D) pores and an in-situ approach during the synthesis of MOF-5 with its 3D channel network. The maximum amount of flavin dye incorporation is 3.9 wt% for MIA@MIL-53(Al) and 1.5 wt% for 6F-MIA@MIL-53(Al), 0.85 wt% for MIA@MOF-5 and 5.2 wt% for 6F-MIA@MOF-5. For the high incorporation yields the probability to have more than one dye molecule in a pore volume is significant. As compared to the flavins in solution, the fluorescence spectrum of these flavin@MOF composites is broadened at the bathocromic side especially for MIA. Time-resolved spectroscopy showed that multi-exponential fluorescence lifetimes were needed to describe the decays. The fluorescence-weighted lifetime of flavin@MOF of 4 ± 1 ns also corresponds to those in solution but is significantly prolonged compared to the solid flavin dyes with less than 1 ns, thereby confirming the concept of “solid solutions” for dye@MOF composites. The fluorescence quantum yield (Φ_F) of the flavin@MOF composites is about half of the solution but is significantly higher compared to the solid flavin dyes. Both the fluorescence lifetime and quantum yield of flavin@MOF decrease with the flavin loading in MIL-53 due to the formation of various J-aggregates. Theoretical calculations using plane-wave and QM/MM methods are in good correspondence with the experimental results and explain the electronic structures as well as the photophysical properties of crystalline MIA and the flavin@MOF composites. In the solid flavins, π-stacking interactions of the molecules lead to a charge transfer state with low oscillator strength resulting in aggregation-caused quenching (ACQ) with low lifetimes and quantum yields. In the MOF pores, single flavin molecules represent a major population and the computed MIA@MOF structures do not find π-stacking interactions with the pore walls but only weak van-der-Waals contacts which reasons the enhanced fluorescence lifetime and quantum yield of the flavins in the composites compared to their neat solid state. To analyze the orientation of flavins in MOFs, we measured fluorescence anisotropy images of single flavin@MOF-5 crystals and a static ensemble flavin@MIL53 microcrystals, respectively. Based on image information, anisotropy distributions and overall curve of the time-resolved anisotropy curves combined with theoretical calculations, we can prove that all fluorescent flavins species have a defined and rather homogeneous orientation in the MOF framework. In MIL-53, the transition dipole moments of flavins are orientated along the 1D channel axis, whereas in MOF-5 we resolved an average orientation that is tilted with respect to the cubic crystal lattice. Notably, the more hydrophobic 6F-MIA exhibits a higher degree order than MIA. The flexible MOF MIL-53(Al) was optimized essentially to the experimental large-pore form in the guest-free state with QuantumEspresso (QE) and with MIA molecules in the pores the structure contracted to close to the experimental narrow-pore form which was also confirmed by PXRD. In summary, the incorporation of flavins in MOFs yields solid-state materials with enhanced rigidity, stabilized conformation, defined orientation and reduced aggregations of the flavins, leading to increased fluorescence lifetime and quantum yield as controllable photo-luminescent and photo-physical properties. Full article

(This article belongs to the Special Issue Porous Materials: Synthetic Strategies and Applications)

► Show Figures

Graphical abstract

20 pages, 4856 KiB

Open AccessArticle

Erythromycin Scavenging from Aqueous Solutions by Zeolitic Materials Derived from Fly Ash

by Agnieszka Grela, Joanna Kuc, Agnieszka Klimek, Jakub Matusik, Justyna Pamuła, Wojciech Franus, Kamil Urbański and Tomasz Bajda

Molecules 2023, 28(2), 798; https://doi.org/10.3390/molecules28020798 - 13 Jan 2023

Cited by 3 | Viewed by 1859

Abstract

Erythromycin (EA) is an antibiotic whose concentration in water and wastewater has been reported to be above the standard levels. Since the methods used so far to remove EA from aquatic environments have not been effective, the development of effective methods for EA removal is necessary. In the present study, fly ash (FA)-based zeolite materials, which have not been investigated as EA sorbents before, were used. The possibilities of managing waste FA and using its transformation products for EA sorption were presented. The efficiency of EA removal from experimental solutions and real wastewater was evaluated. In addition, the sorbents’ mineral composition, chemical composition, and physicochemical properties and the effects of adsorbent mass, contact time, initial EA concentration, and pH on EA removal were analyzed. The EA was removed within the first 2 min of the reaction with an efficiency of 99% from experimental solutions and 94% from real wastewater. The maximum adsorption capacities were 314.7 mg g⁻¹ for the fly ash-based synthetic zeolite (NaP1_FA) and 363.0 mg g⁻¹ for the carbon–zeolite composite (NaP1_C). A fivefold regeneration of the NaP1_FA and NaP1_C showed no significant loss of adsorption efficiency. These findings indicate that zeolitic materials effectively remove EA and can be further investigated for removing other pharmaceuticals from water and wastewater. Full article

(This article belongs to the Special Issue Porous Materials: Synthetic Strategies and Applications)

► Show Figures

Figure 1

18 pages, 8613 KiB

Open AccessArticle

Step-By-Step Modeling and Demetallation Experimental Study on the Porous Structure in Zeolites

by Pavel Kononov, Irina Kononova, Vyacheslav Moshnikov, Evgeniya Maraeva and Olga Trubetskaya

Molecules 2022, 27(23), 8156; https://doi.org/10.3390/molecules27238156 - 23 Nov 2022

Viewed by 1254

Abstract

The organization of microporous space in zeolites is discussed. A new step-by-step model is proposed that explains the principles of organizing the hierarchy of microporous space at the stage of assembling zeolites from elements of minimal size: a primary building unit, secondary building units, tertiary building units or building polyhedra, a sodalite cage, and a supercage. To illustrate the stepwise hierarchical porous structure of nanomaterials, the following zeolites with small and large micropores have been selected as the model objects: sodalite (SOD, the maximum diameter of a sphere that can enter the pores is 0.3 nm) and zeolites of type A (LTA, the maximum diameter of a sphere that can enter the pores is 0.41 nm), type X, Y (FAU, the maximum diameter of a sphere that can enter the pores is 0.75 nm), and type BETA (the maximum diameter of a sphere that can enter the pores is 0.67 nm). Two-dimensional and three-dimensional modeling in 3Ds Max software was used. We believe that such an approach will be useful for developing ways to create complex zeolite compositions for specific applications, such as catalysis, where the geometry of the pores determines the size of the molecules entering the voids and computer modeling can play an important predictive role. This work takes a look at specific aspects of using the heat desorption method to study mesoporous materials with a BETA zeolite as an example and presents the results of experimental research into the characteristics of the porous structure of hierarchically structured zeolite materials (specific surface area 180–380 m²/g, external surface area 120–200 m²/g, micropore volume 0.001–0.1 mL/g). Full article

(This article belongs to the Special Issue Porous Materials: Synthetic Strategies and Applications)

► Show Figures

Figure 1

14 pages, 4321 KiB

Open AccessArticle

Facile Solution-Refluxing Synthesis and Photocatalytic Dye Degradation of a Dynamic Covalent Organic Framework

by Xiao-Lian Wang, Yi-Ying Sun, Yonghong Xiao, Xiao-Xian Chen, Xiao-Chun Huang and Hao-Long Zhou

Molecules 2022, 27(22), 8002; https://doi.org/10.3390/molecules27228002 - 18 Nov 2022

Cited by 8 | Viewed by 1891

Abstract

Covalent organic frameworks (COFs), as a novel crystalline porous adsorbent, have been attracting significant attention for their synthesis and application exploration due to the advantages of designability, stability, and functionalization. Herein, through increasing the concentration of the acid catalyst, a facile solution-refluxing synthesis method was developed for the preparation of a three-dimensional dynamic COF material, COF-300, with high yields (>90%) and high space–time yields (>28 kg m^–3 day^–1). This synthesis method not only permits gram-scale synthesis, but also yields products that well maintain porosity and unique guest-dependent dynamic behavior. Moreover, the catalytic activity of COF-300 as a metal-free photocatalyst was explored for the first time. Under 365 nm ultra-violet light irradiation, COF-300 can effectively catalyze the dye degradation (>99%) in wastewater with good recyclability. By adding magnetic Fe₃O₄ nanoparticles into the solution-refluxing synthesis of COF-300, Fe₃O₄/COF-300 nanocomposites can be obtained and used as magnetically recyclable photocatalysts, demonstrating the superiority of this facile synthesis procedure. Our study provides new insights for the preparation of COF materials and a constructive exploration for their water treatment application. Full article

(This article belongs to the Special Issue Porous Materials: Synthetic Strategies and Applications)

► Show Figures

Journal Menu

Journal Browser

Porous Materials: Synthetic Strategies and Applications

Share This Special Issue

Special Issue Editors

Special Issue Information

Published Papers (5 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI