The Fluorescence Property of Zirconium-Based MOFs Adsorbed Sulforhodamine B

Transition metal supported UiO-67 materials and their applications in catalysis

Metal-organic frameworks (MOFs) have emerged as promising platforms for heterogeneous catalysis due to their tunable structures and high specific surface areas. Results indicate that modified composite MOFs not only exhibit superior water stability but also demonstrate broader applicability in catalysis, such as Fenton-like oxidation, Morita-Baylis-Hillman reactions, ethylene dimerization, and various photoelectrochemical processes. Among them, UiO-67, a zirconium-based MOF, has attracted extensive attention for its exceptional chemical stability, high catalytic activity, and well-defined microporous structure. This review introduces composites formed by different types of single and multi-metal loadings on UiO-67 and their demonstrated catalytic performance. It emphasizes the structure-performance relationships of these composites, highlighting how metal loading and spatial distribution influence their reactivity and stability. The current application status and existing challenges of UiO-67 series materials and their derivatives in catalysis are systematically reviewed. By integrating experimental results and mechanistic insights, this work underscores the transformative potential of UiO-67 series materials in meeting the demands of sustainable catalysis.

A chitosan/MOF hybrid monolith with improved stability and enhanced adsorption performances via a pre-frozen crosslinking route

In wastewater remediation by adsorption, three-dimensional porous MOF (metal-organic frame)/polymer hybrid monoliths have been demonstrated to be promising absorbents with effective adsorption and recovery capacities. However, MOF/polymer monoliths often suffer from obvious decrease of porous structures due to large shrinkage during dry at room temperature, weakening the accessibility of active sites for adsorption. Here, a so-called pre-frozen crosslinking process is employed for fabrication of a chitosan/UiO-66 monolith, of which shrinkage is restrained markedly during drying in the air, and the shape of the monolith can be kept intact in 6.3 M acetic acid (CH3COOH), deionized water and 1 M sodium hydroxide (NaOH) for 60 days. Furthermore, the monolith achieves an adsorption capacity of 55.50 mg g-1 for methylchlorophenoxypropionic acid (MCPP) from its aqueous solution, increasing by 55.6% compared with UiO-66 particles, and the maximum adsorption capacity is 256.41 mg g-1.

Recent Progress and Future Prospects of Laccase Immobilization on MOF Supports for Industrial Applications

Laccase is a multicopper oxidoreductase enzyme that can oxidize organics such as phenolic compounds. Laccases appear to be unstable at room temperature, and their conformation often changes in a strongly acidic or alkaline environment, making them less effective. Therefore, rationally linking enzymes with supports can effectively improve the stability and reusability of native enzymes and add important industrial value. However, in the process of immobilization, many factors may lead to a decrease in enzymatic activity. Therefore, the selection of a suitable support can ensure the activity and economic utilization of immobilized catalysts. Metal-organic frameworks (MOFs) are porous and simple hybrid support materials. Moreover, the characteristics of the metal ion ligand of MOFs can enable a potential synergistic effect with the metal ions of the active center of metalloenzymes, enhancing the catalytic activity of such enzymes. Therefore, in addition to summarizing the biological characteristics and enzymatic properties of laccase, this article reviews laccase immobilization using MOF supports, as well as the application prospects of immobilized laccase in many fields.

Amplified Spontaneous Emission Threshold Dependence on Determination Method in Dye-Doped Polymer and Lead Halide Perovskite Waveguides

Nowadays, the search for novel active materials for laser devices is proceeding faster and faster thanks to the development of innovative materials able to combine excellent stimulated emission properties with low-cost synthesis and processing techniques. In this context, amplified spontaneous emission (ASE) properties are typically investigated to characterize the potentiality of a novel material for lasers, and a low ASE threshold is used as the key parameter to select the best candidate. However, several different methods are currently used to define the ASE threshold, hindering meaningful comparisons among various materials. In this work, we quantitatively investigate the ASE threshold dependence on the method used to determine it in thin films of dye-polymer blends and lead halide perovskites. We observe a systematic ASE threshold dependence on the method for all the different tested materials, and demonstrate that the best method choice depends on the kind of information one wants to extract. In particular, the methods that provide the lowest ASE threshold values are able to detect the excitation regime of early-stage ASE, whereas methods that are mostly spread in the literature return higher thresholds, detecting the excitation regime in which ASE becomes the dominant process in the sample emission. Finally, we propose a standard procedure to properly characterize the ASE threshold, in order to allow comparisons between different materials.

Bio-adhesive Nanoporous Module: Toward Autonomous Gating

Here we report a bio-adhesive porous organic module (^Glue COF) composed of hexagonally packed 1D nanopores based on a covalent organic framework. The nanopores are densely decorated with guanidinium ion (Gu⁺ ) pendants capable of forming salt bridges with oxyanionic species. ^Glue COF strongly adheres to biopolymers through multivalent salt-bridging interactions with their ubiquitous oxyanionic species. By taking advantage of its strong bio-adhesive nature, we succeeded in creating a gate that possibly opens the nanopores through a selective interaction with a reporter chemical and releases guest molecules. We chose calmodulin (CaM) as a gating component that can stably entrap a loaded guest, sulforhodamine B (SRB), within the nanopores (^CaM COF⊃SRB). CaM is known to change its conformation on binding with Ca²⁺ ions. We confirmed that mixing ^CaM COF⊃SRB with Ca²⁺ resulted in the release of SRB from the nanopores, whereas the use of weakly binding Mg²⁺ ions resulted in a much slower release of SRB.

Confinement-guided photophysics in MOFs, COFs, and cages

In this review, the dependence of the photophysical response of chromophores in the confined environments associated with crystalline scaffolds, such as metal-organic frameworks (MOFs), covalent-organic frameworks (COFs), and molecular cages, has been carefully evaluated. Tunability of the framework aperture, cavity microenvironment, and scaffold topology significantly affects emission profiles, quantum yields, or fluorescence lifetimes of confined chromophores. In addition to the role of the host and its effect on the guest, the methods for integration of a chromophore (e.g., as a framework backbone, capping linker, ligand side group, or guest) are discussed. The overall potential of chromophore-integrated frameworks for a wide-range of applications, including artificial biomimetic systems, white-light emitting diodes, photoresponsive devices, and fluorescent sensors with unparalleled spatial resolution are highlighted throughout the review.