skip to main content


Title: Fabrication of a freestanding metal organic framework predominant hollow fiber mat and its potential applications in gas separation and catalysis
Recently, metal–organic framework (MOF)-based polymeric substrates show promising performance in many engineering and technology fields. However, a commonly known drawback of MOF/polymer composites is MOF crystal encapsulation and reduced surface area. This work reports a facile and gentle strategy to produce self-supported MOF predominant hollow fiber mats. A wide range of hollow MOFs including MIL-53(Al)–NH 2 , Al-PMOF, and ZIF-8 are successfully fabricated by our synthetic method. The synthetic strategy combines atomic layer deposition (ALD) of metal oxides onto polymer fibers and subsequent selective removal of polymer components followed by conversion of remaining hollow metal oxides into freestanding MOF predominant hollow fiber structures. The hollow MOFs show boosted surface area, superb porosity, and excellent pore accessibility, and exhibit a significantly improved performance in CO 2 adsorption (3.30 mmol g −1 ), CO 2 /N 2 separation selectivity (24.9 and 21.2 for 15/85 and 50/50 CO 2 /N 2 mixtures), and catalytic removal of HCHO (complete oxidation of 150 ppm within 60 min).  more » « less
Award ID(s):
1704151
NSF-PAR ID:
10147519
Author(s) / Creator(s):
; ; ; ; ; ; ; ;
Date Published:
Journal Name:
Journal of Materials Chemistry A
Volume:
8
Issue:
7
ISSN:
2050-7488
Page Range / eLocation ID:
3803 to 3813
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract

    This personal account concerns novel recent discoveries in the area of mesoporous materials. Most of the papers discussed have been published within the last two to three years. A major emphasis of most of these papers is the synthesis of unique mesoporous materials by a variety of synthetic methods. Many of these articles focus on the control of the pore sizes and shapes of mesoporous materials. Synthetic methods of various types have been used for such control of porosity including soft templating, hard templating, nano‐casting, electrochemical methods, surface functionalization, and trapping of species in pores. The types of mesoporous materials range from carbon materials, metal oxides, metal sulfides, metal nitrides, carbonitriles, metal organic frameworks (MOFs), and composite materials. The vast majority of recent publications have centered around biological applications with a majority dealing with drug delivery systems. Several other bio‐based articles on mesoporous systems concern biomass conversion and biofuels, magnetic resonance imaging (MRI) studies, ultrasound therapy, enzyme immobilization, antigen targeting, biodegradation of inorganic materials, applications for improved digestion, and antitumor activity. Numerous nonbiological applications of mesoporous materials have been pursued recently. Some specific examples are photocatalysis, photo‐electrocatalysis, lithium ion batteries, heterogeneous catalysis, extraction of metals, extraction of lanthanide and actinide species, chiral separations and catalysis, capturing and the mode of binding of carbon dioxide (CO2), optical devices, and magneto‐optical devices. Of this latter class of applications, heterogeneous catalysis is predominant. Some of the types of catalytic reactions being pursued include hydrogen generation, selective oxidations, aminolysis, Suzuki coupling and other coupling reactions, oxygen reduction reactions (ORR), oxygen evolution reactions (OER), and bifunctional catalysis. For perspective, there have been over 40,000 articles on mesoporous materials published in the last 4 years and about 1388 reviews. By no means is this personal account thorough or all inclusive. One objective has been to choose a variety of articles of different types to obtain a flavor of the breadth of diversity involved in the area of mesoporous materials.

     
    more » « less
  2. Abstract

    Despite the high potential of zeolite MFI membranes for the separation of important hydrocarbons, their impact on industrial hydrocarbon separations has been limited by challenges in scalable fabrication methods and use of high‐cost membrane supports. Here a one‐step method for fabrication of highly selective and thin (<1 µm) MFI zeolite membranes on low‐cost α‐alumina hollow fiber supports is demonstrated. This is enabled by use of a highly concentrated silicate precursor gel containing MFI nanocrystals that induces a compact membrane layer at the support surface in a single‐step membrane synthesis. These one‐step crystallized MFI hollow fiber membranes show excellent characteristics for butane isomer separation (n‐butane permeance > 10−7mol m−2s−1Pa−1andn‐butane/i‐butane separation factors > 50 ), as well as for removal of natural gas liquids (butane, propane, and ethane) from methane at elevated feed pressures up to 9 bar. It is further demonstrated that the scalability of the current strategy by successful fabrication of a high‐quality ten‐membrane module in a single synthesis batch.

     
    more » « less
  3. null (Ed.)
    Ionic liquid based fiber welding has been used to attach the metal−organic framework (MOF) UiO-66-NH2to cotton fibers. The results show that by controlling the extent of the welding process, it is possible to produce fibers that contain a high surface area (approximately 50−100 m2/ g), an X-ray diffraction pattern consistent with UiO-66-NH2, and fibers that are chemically reactive to dimethyl 4-nitrophenyl phosphate (DMNP), a common chemical weapon simulant. The ionic liquid/MOF welding solution can be applied by directly placing the fabric in the welding solution or by utilizing an airbrushing technique. Both welding techniques are shown to be scalable with results collected on approximately 1×1, 5 ×5, and 15.5×15.5 in. swatches. The results are also applicable to weaving methods where the MOF is welded to individual threads and subsequently woven into a textile. The results provide an industrially scalable method of attaching a wide variety of MOFs to cotton textiles, which does not require synthesizing the MOF in the presence of the textile. 
    more » « less
  4. Abstract

    Mesoporous silica is a versatile material for energy, environmental, and medical applications. Here, for the first time, we report a flame aerosol synthesis method for a class of mesoporous silica with hollow structure and specific surface area exceeding 1000 m2 g−1. We show its superior performance in water purification, as a drug carrier, and in thermal insulation. Moreover, we propose a general route to produce mesoporous nanoshell‐supported nanocatalysts by in situ decoration with active nanoclusters, including noble metal (Pt/SiO2), transition metal (Ni/SiO2), metal oxide (CrO3/SiO2), and alumina support (Co/Al2O3). As a prototypical application, we perform dry reforming of methane using Ni/SiO2, achieving constant 97 % CH4and CO2conversions for more than 200 hours, dramatically outperforming an MCM‐41 supported Ni catalyst. This work provides a scalable strategy to produce mesoporous nanoshells and proposes an in situ functionalization mechanism to design and produce flexible catalysts for many reactions.

     
    more » « less
  5. Abstract

    Mesoporous silica is a versatile material for energy, environmental, and medical applications. Here, for the first time, we report a flame aerosol synthesis method for a class of mesoporous silica with hollow structure and specific surface area exceeding 1000 m2 g−1. We show its superior performance in water purification, as a drug carrier, and in thermal insulation. Moreover, we propose a general route to produce mesoporous nanoshell‐supported nanocatalysts by in situ decoration with active nanoclusters, including noble metal (Pt/SiO2), transition metal (Ni/SiO2), metal oxide (CrO3/SiO2), and alumina support (Co/Al2O3). As a prototypical application, we perform dry reforming of methane using Ni/SiO2, achieving constant 97 % CH4and CO2conversions for more than 200 hours, dramatically outperforming an MCM‐41 supported Ni catalyst. This work provides a scalable strategy to produce mesoporous nanoshells and proposes an in situ functionalization mechanism to design and produce flexible catalysts for many reactions.

     
    more » « less