Photocatalytic Metal Organic Frameworks Research Articles

Engineering ZIF-67 loaded nanofibrous membrane with thermal stabilization treatment for efficient photocatalytic CO2 reduction

The photocatalytic Metal-organic frameworks (MOFs) membrane addresses challenges faced by MOF powders in practical applications such as aggregation and difficult recovery, but its current application is mainly confined to wastewater treatment. Expanding the application of MOFs membranes to CO2 reduction could unleash their greater potential in energy conversion and storage field. In this study, ZIF-67 was deposited on polyacrylonitrile (PAN) nanofiber membranes (NFMs) using an in-situ growth technique, followed by thermal stabilization to produce SZIF-67/PAN NFMs for photocatalytic CO2 reduction. ZIF-67 was uniformly and densely distributed on the NFMs, with a mass loading of up to 8 wt%. The thermal stabilization process significantly enhanced the photothermal conversion capability and solvent resistance of the NFMs, enabling SZIF-67/PAN NFMs to exhibit outstanding photocatalytic activity even under mild environmental conditions, with a remarkable CO generation rate of 39,250 μmol g−1h−1. Furthermore, the performance remained at 70 % even after five consecutive tests. This study presents a novel and effective method for preparing MOF NFMs with excellent photocatalytic CO2 reduction performance, offering valuable insights for advancing the practical application of MOF materials.

Recycling of polyethylene terephthalate to bismuth-embedded bimetallic MOFs as photocatalysts toward removal of cationic dye in water

Our study presents a sustainable approach to fabricating efficient photocatalytic metal–organic frameworks (MOFs) by recycling polyethylene terephthalate (PET) waste from bottles. Through chemical depolymerization, recycled terephthalic acids (BDCs) obtained from PET waste were coordinated with copper (Cu) and nickel (Ni) to prepare a bimetallic Ni/Cu-MOF. After exploring various Ni:Cu ratios (1:3, 2:3, and 3:3), we determined that the 2:3 ratio represents the optimal metal combination (degradation efficiency 50–60% under direct sunlight). Subsequently, we integrated bismuth oxyiodide (BiOI) into the Ni/Cu-BDC MOF, yielding Ni/Cu-MOF@BiOI heterostructures. Thorough structural characterization via scanning electron microscopy and X-ray diffraction confirmed the morphology and composition of the prepared materials. Assessing the photocatalytic performance against methylene blue (MB) degradation in water under solar irradiation, we systematically analyzed operational parameters such as pH, catalyst dosage, MB concentration, and irradiation time. Ni/Cu-MOF@BiOI heterostructures exhibited exceptional efficiency, degrading 99% of MB under sunlight in four hours. Our research presents a sustainable method for the synthesis of photocatalysts using recycled PET waste, along with optimized operational parameters for enhanced catalytic efficiency. This approach combines green synthesis, material hybridization, and thorough analysis, contributing significantly to sustainable materials for pollutant remediation.

MIL-101-NH2(Fe)-Coated Nylon Microfibers for Immobilized Photocatalysts in RhB and Cr(VI) Removal.

MIL-101-NH2(Fe) is one of the effective photocatalytic metal-organic frameworks (MOFs) working under visible light. However, its powder-type form inhibits reusability in practical applications. In this study, we immobilized MIL-101-NH2(Fe) on a polymeric microfiber mesh to improve reusability while minimizing the loss of catalytic performance. To overcome the lack of surface functionality of the nylon fibers, an atomic layer deposition Al2O3 layer and NH2-BDC linker were introduced to facilitate uniform coating of the MOF on the fiber surface. The reactions of the metal precursor to the nylon substrate and NH2-BDC ligand of the MOF allow chemical bonding from the core to the shell of the entire hybrid catalytic materials. The resulting fiber-immobilized MOFs (Nylon@Al2O3@MOF) demonstrated high photocatalytic performance in the removal of RhB and Cr(VI) as representatives of organic dyes and heavy metals, respectively, while retaining over 85% of its efficiency after five cycles.

Modeling Adsorption and Optical Properties for the Design of CO2 Photocatalytic Metal-Organic Frameworks.

Four Metal-Organic Frameworks (MOFs) were modeled (IRMOF-C-BF2, IRMOF-C-(2)-BF2, IRMOF-C’-BF2, and IRMOF-C-CH2BF2) based on IRMOF-1. A series of linkers, based on Frustrated Lewis Pairs and coumarin moieties, were attached to IRMOF-1 to obtain MOFs with photocatalytic properties. Four different linkers were used: (a) a BF2 attached to a coumarin moiety at position 3, (b) two BF2 attached to a coumarin moiety in positions 3 and 7, (c) a BF2 attached in the coumarin moiety at position 7, and (d) a CH2BF2 attached at position 3. An analysis of the adsorption properties of H2, CO2, H2O and possible CO2 photocatalytic capabilities was performed by means of computational modeling using Density Functional Theory (DFT), Time-Dependent Density Functional (TD-DFT) methods, and periodic quantum chemical wave function approach. The results show that the proposed linkers are good enough to improve the CO2 adsorption, to hold better bulk properties, and obtain satisfactory optical properties in comparison with IRMOF-1 by itself.

Simple and Continuous Fabrication of Self-Propelled Micromotors with Photocatalytic Metal-Organic Frameworks for Enhanced Synergistic Environmental Remediation.

This work reports on a simple and general strategy for continuous fabrication of self-propelled micromotors with photocatalytic metal-organic frameworks (MOFs) for enhanced synergistic degradation of organic contaminants. With emulsion microdroplets from microfluidics as templates, uniform porous micromotors decorated with Fe3O4@Ag nanoparticles (Fe3O4@AgNPs) at the bottom and zeolitic imidazolate framework-8@ZnO nanoparticles (ZIF-8@ZnONPs) on the surface can be synthesized. The spatial location of ZIF-8@ZnONPs and Fe3O4@AgNPs in micromotors is accurately controlled in one step via their directional migration in the confined microspace of emulsion droplets driven by interfacial energy and magnetic field. The nanoengines Fe3O4@AgNPs enable asymmetric decomposition of H2O2 for bubble-propelled motion and easy magnetic recycling of the micromotor. The porous structures of micromotors provide a large surface area, benefiting decoration of Fe3O4@AgNPs and their contact with H2O2 for promoting bubble generation and reduced micromotor weight for promoting bubble-propelled motion. The nanophotocatalysts ZIF-8@ZnONPs allow enrichment of organic contaminant molecules via adsorption for efficient photocatalytic degradation. With synergistic coupling of the photocatalysis of ZIF-8@ZnONPs and advanced oxidation of the H2O2/UV system, the micromotors with bubble-propelled motion for improved mixing can achieve enhanced degradation of organic contaminants via dual synergistic degradation mechanisms. As highlighted by degradation of rhodamine B, the micromotors exhibit the highest degradation performance as compared to control groups with a single degradation mechanism and with dual degradation mechanisms but without self-propelled motion. This simple fabrication strategy is general and can be flexibly extended to other MOF materials, which may open up new avenues for developing advanced MOF-integrated micromotors for myriad applications.

Metal–Organic Frameworks (MOFs) and Covalent Organic Frameworks (COFs) Applied to Photocatalytic Organic Transformations

Among the different alternatives for catalysis using metal–organic frameworks (MOFs) or covalent organic frameworks (COFs), photocatalysis has remarkably evolved during the last decade. Photocatalytic reticular materials allowed recyclability and easy separation of catalyst from the product, also reaching the activity and selectivity commonly observed for molecular systems. Recently, photocatalytic MOFs and COFs have been applied to synthetic applications in order to obtain organic molecules of different complexity. However, although a good number of works have been devoted to this issue, an updated comprehensive revision on this field is still needed. The aim of this review was to fill this gap covering the following three general aspects: (1) common strategies on the design of reticular photocatalytic materials, (2) a comprehensive discussion of the photocatalytic organic reactions achieved by the use of COFs and MOFs, and (3) some critical considerations highlighting directions that should be considered in order to make advances in the study of photocatalytic COFs and MOFs.

Crystal-to-Crystal Synthesis of Photocatalytic Metal-Organic Frameworks for Visible-Light Reductive Coupling and Mechanistic Investigations.

Postmodification of reticular materials with well-defined catalysts is an appealing approach to produce new catalytic functional materials with improved stability and recyclability, but also to study catalysis in confined spaces. A promising strategy to this end is the postfunctionalization of crystalline and robust metal-organic frameworks (MOFs) to exploit the potential of crystal-to-crystal transformations for further characterization of the catalysts. In this regard, two new photocatalytic materials, MOF-520-PC1 and MOF-520-PC2, are straightforwardly obtained by the postfunctionalization of MOF-520 with perylene-3-carboxylic acid (PC1) and perylene-3-butyric acid (PC2). The single crystal-to-crystal transformation yielded the X-ray diffraction structure of catalytic MOF-520-PC2. The well-defined disposition of the perylenes inside the MOF served as suitable model systems to gain insights into the photophysical properties and mechanism by combining steady-state, time-resolved, and transient absorption spectroscopy. The resulting materials are active organophotoredox catalysts in the reductive dimerization of aromatic aldehydes, benzophenones, and imines under mild reaction conditions. Moreover, MOF-520-PC2 can be applied for synthesizing gram-scale quantities of products in continuous-flow conditions under steady-state light irradiation. This work provides an alternative approach for the construction of well-defined, metal-free, MOF-based catalysts.

Photocatalytic Metal-Organic Frameworks for Selective 2,2,2-Trifluoroethylation of Styrenes.

Synthesis of CF3-containing compounds is of great interest because of their broad use in the pharmaceutical and agrochemical industries. Herein, selective 2,2,2-trifluoroethylation of styrenes was catalyzed by Zr(IV)-based MOFs bearing visible-light photocatalysts in the form of Ir(III) polypyridyl complexes. When compared to the homogeneous Ir(III) catalyst, the MOF-based catalyst suppressed the dimerization of benzyl radicals, thus enhancing the selectivity of the desired hydroxytrifluoroethyl compounds.

Photocatalytic metal-organic frameworks for the aerobic oxidation of arylboronic acids.

A photocatalytic Ru complex was incorporated into a Zr(iv)-based metal-organic framework (MOF) via postsynthetic methods. The resulting UiO-67-Ru(bpy)3 shows efficient and recyclable catalytic activity for the aerobic oxidation of arylboronic acids under near-UV and visible light irradiation.