Anion exchange membrane fuel cells (AEMFCs) offer several advantages over proton exchange membrane fuel cells, such as the use of a non‐precious metal catalyst, but these cells suffer from various ...issues related to OH–‐conducting electrolytes, including low conductivity and the formation of K2CO3 salt. These issues need to be resolved for the widespread use of AEMFCs. Recently, many studies have focused on developing excellent ion‐conductive electrolytes using porous materials based on metal–organic and covalent organic frameworks. However, most of this research is biased toward proton‐conducting electrolytes; to the best of the authors’ knowledge, reviews addressing OH–‐conducting electrolytes using porous materials have not been reported thus far. This review discusses OH–‐conducting porous crystalline materials and their membranes in terms of different synthetic strategies, conduction mechanisms, and experimental modalities for the design and development of future anion conductive electrolytes in fuel cells.
This review provides a comprehensive overview of solid electrolytes based on crystalline porous materials and their composite materials for use in anion exchange membrane fuel cells.
Thin‐films of metal‐organic frameworks (MOFs) have widespread potential applications, especially with the emergence of glass‐forming MOFs, which remove the inherent issue of grain boundaries and ...allow coherent amorphous films to be produced. Herein, it is established that atomic layer deposition (ALD) of zinc oxide lends excellent control over the thickness and localization of resultant polycrystalline and glass zeolitic imidazole framework‐62 (ZIF‐62) thin‐films within tubular α‐alumina supports. Through the reduction of the chamber pressure and dose times during zinc oxide deposition, the resultant ZIF‐62 films are reduced from 38 µm to 16 µm, while the presence of sporadic ZIF‐62 (previously forming as far as 280 µm into the support) is prevented. Furthermore, the glass transformation shows a secondary reduction in film thickness from 16 to 2 µm.
Control of localized metal organic film thickness is shown through the variation of chamber pressure and dose time during atomic layer deposition (ALD). Zinc oxide is deposited within α‐alumina tubular supports, solvothermally converted to zeolitic imidazole framework‐62 (ZIF‐62), and subsequently melt treated into an amorphous glass (agZIF‐62). Through variation of the ALD conditions, the ZIF‐62 films are reduced from 38 µm to 16 µm, while the agZIF‐62 films are reduced from 16 to 2 µm.
•High-throughput computational screening of 4738 MOFs and 296 COFs was performed.•IL/MOFs have higher CH4/N2 selectivities than pristine MOFs.•MOF/polymer and COF/polymer composites doubled the N2 ...permeabilities of polymers.
Separating CH4/N2 mixture is challenging, and performance of the existing materials is still open to improvement. In this study, we examined both the adsorption- and membrane-based CH4/N2 separation performances of 5034 different materials, including metal organic frameworks (MOFs), covalent organic frameworks (COFs), ionic liquid (IL)/MOF composites, MOF/polymer composites, and COF/polymer composites by performing high-throughput computational screening and molecular simulations. The top performing adsorbents and membranes were identified by computing several performance evaluation metrics. Investigation of the interactions between the gas molecules, the IL, and the top MOF was performed by density functional theory (DFT) calculations. Results pointed out that the interactions between the gas molecules and the linker fragments of the MOF are stronger than their interactions with the IL. Thus, as the IL molecules are loaded into the selected top MOF, they occupy the adsorption sites of the gases, decreasing CH4 and N2 uptakes and increasing the CH4/N2 selectivity. Our results revealed that MOFs offer great potential for adsorption-based CH4/N2 separation, and IL incorporation into MOFs remarkably increases their CH4/N2 selectivities. More than 25% of MOF and 70% of the COF membranes surpassed Robeson’s upper bound because of high N2 permeabilities and outperformed conventional polymeric membranes. N2 permeabilities and selectivities of MOF/polymer and COF/polymer composites were found to be significantly higher than those of pure polymers. Our results emphasize the promises of the design and development of new MOF and COF adsorbents, membranes, and their composites with ILs and polymers for efficient CH4/N2 separation.
Many renewable energy technologies, especially batteries and supercapacitors, require effective electrode materials for energy storage and conversion. For such applications, metal‐organic frameworks ...(MOFs) and covalent‐organic frameworks (COFs) have been recently emerged as promising candidates. Their high surface area, organized channel, and multiple functions make them highly versatile and flexible as electrodes, electrolytes, and electrocatalysts in electrochemical energy storage (EES) systems. In addition, many MOFs/COFs‐derived materials tend to possess high conductivity and diverse nanoarchitecture, and can also serve as high‐performance electrodes. In this review, we summarize the extensive potentials of both frameworks and their derivatives in a range of devices, including lithium/sodium ion, lithium‐sulfur, lithium‐oxygen batteries, and supercapacitors. In addition, we discuss the remaining challenges in this area and propose potential solutions for them as well as outline a few possible directions for further development for EES applications.
Metal/covalent organic frameworks (MOFs/COFs) have received wide attention for electrochemical energy storage (EES) due to their unique structural characteristics. Herein, we summarize the applications of MOFs/COFs and their derivatives in EES, including lithium/sodium ion, lithium‐sulfur, lithium‐oxygen batteries, and supercapacitors. Moreover, the development perspective of MOFs/COFs in EES is also outlined.
It has become clear that superior material functions are derived from precisely controlled nanostructures. This has been greatly accelerated by the development of nanotechnology. The next step is to ...assemble materials with knowledge of their nano-level structures. This task is assigned to the post-nanotechnology concept of nanoarchitectonics. However, nanoarchitectonics, which creates intricate three-dimensional functional structures, is not always easy. Two-dimensional nanoarchitectonics based on reactions and arrangements at the surface may be an easier target to tackle. A better methodology would be to define a two-dimensional structure and then develop it into a three-dimensional structure and function. According to these backgrounds, this review paper is organized as follows. The introduction is followed by a summary of the three issues; (i) 2D to 3D dynamic structure control: liquid crystal commanded by the surface, (ii) 2D to 3D rational construction: a metal-organic framework (MOF) and a covalent organic framework (COF); (iii) 2D to 3D functional amplification: cells regulated by the surface. In addition, this review summarizes the important aspects of the ultimate three-dimensional nanoarchitectonics as a perspective. The goal of this paper is to establish an integrated concept of functional material creation by reconsidering various reported cases from the viewpoint of nanoarchitectonics, where nanoarchitectonics can be regarded as a method for everything in materials science.
Fe‐HHTP‐MOF , ein einzigartiges kubisches metallorganisches Gerüst (MOF), das aus supertetraedrischen Hexahydroxytriphenylen(HHTP)‐Einheiten und in Rautentopologie angeordneten FeIII‐Ionen aufgebaut ...ist, wird im Forschungsartikel auf S. 18213 von Thomas Bein, Dana D. Medina et al. vorgestellt. Fe‐HHTP‐MOF ist ein hochkristallines, poröses und tiefschwarzes Material, das eine hohe elektrische Leitfähigkeit aufweist.
Chronic diabetic wounds remain a worldwide challenge for both the clinic and research. Given the vicious circle of oxidative stress and inflammatory response as well as the impaired angiogenesis of ...the diabetic wound tissues, the wound healing process is disturbed and poorly responds to the current treatments. In this work, a nickel‐based metal‐organic framework (MOF, Ni‐HHTP) with excellent antioxidant activity and proangiogenic function is developed to accelerate the healing process of chronic diabetic wounds. The Ni‐HHTP can mimic the enzymatic catalytic activities of antioxidant enzymes to eliminate multi‐types of reactive species through electron transfer reactions, which protects cells from oxidative stress‐related damage. Moreover, this Ni‐based MOF can promote cell migration and angiogenesis by activating transforming growth factor‐β1 (TGF‐β1) in vitro and reprogram macrophages to the anti‐inflammatory phenotype. Importantly, Ni‐HHTP effectively promotes the healing process of diabetic wounds by suppressing the inflammatory response and enhancing angiogenesis in vivo. This study reports a versatile and promising MOF‐based nanozyme for diabetic wound healing, which may be extended in combination with other wound dressings to enhance the management of diabetic or non‐healing wounds.
A nickel‐based metal‐organic framework‐based nanozyme (Ni‐HHTP) with electron transport function as well as nickel superoxide dismutase is designed to simultaneously eliminate reactive oxygen and nitrogen species (RONS) and enhance angiogenesis for the treatment of chronic diabetic wounds. Ni‐HHTP significantly accelerates the healing process of diabetic wounds in vivo by suppressing inflammatory responses and promoting angiogenesis.
Brolly good MOFs: A new series of hydrophobic isoreticular porous Zr oxide dicarboxylate MOFs have been prepared (see picture, Zr blue polyhedra, O red, C black). They have a one‐dimensional pore ...system, a rare combination of Lewis acidity and hydrophobic character, and a higher hydrothermal and mechanical stability than their UiO MOF polymorph counterparts.
Zeolitic imidazolate framework‐8 (ZIF‐8) grown around antibodies anchored to plasmonic nanostructures serves as a protective layer to preserve the biorecognition ability of antibodies stored at room ...and elevated temperatures for several days. The biofunctionality of the ZIF‐8‐protected biochip can be restored by a simple water‐rinsing step, making it highly convenient for use in point‐of‐care and resource‐limited settings.
PDF
