A novel dual-ligand Fe-based MOFs synthesized with dielectric barrier discharge (DBD) plasma as efficient photocatalysts

Synthesis of a novel cost-effective double-ligand Zr-based MOF via an inverted modulator strategy towards enhanced adsorption and photodegradation of tetracycline

Developing visible-light response photocatalysts with high activity and adsorption alongside sustainability is vitally important to environmental restoration. Here, we fabricated a novel metal organic framework (MOF) with cost-effective double-ligands (fumaric acid and 2-aminoterephthalic acid as ligand precursors, denoted as MA-MOF) via a facile solvothermal method. Specifically, crystalline [Zr6O4(OH)4(fumarate)6] (MOF-801) can be only formed with monocarboxylic acids as modulators. Therefore, in the construction of crystalline double-ligand MA-MOF, the absence of monocarboxylic acid modulators successfully prevents the formation of crystalline MOF-801. Instead, the crystalline double-ligand MA-MOF is formed. Properties of MA-MOFs including the surface area, porosity, charge transfer resistance, and energy level position can be adjusted via altering the ratio of ligands. The optimal sample, MA-MOF2 (prepared with a molar ratio of fumaric acid and 2-aminoterephthalic acid being 2:1), shows a total 94.6% removal of tetracycline via adsorption and photodegradation, far exceeding the corresponding single-ligand counterparts. This work proposes an innovative inverted modulator strategy for constructing double-ligand MOFs.

Plasma-assisted assembly of Co3O4/TiO2-NRs for photoelectrocatalytic degradation of bisphenol A in solution and muddy systems

Herein, Co3O4/TiO2-NRs electrodes with excellent photoresponse have been prepared via the plasma-assisted modification of Co3O4 on TiO2. With the combination of Co3O4 and TiO2, the composite electrode exhibited a red-shift phenomenon and the absorption of UV and visible light were enhanced to improve the light utilization efficiency. The Mott-Schottky diagram showed that a P-N heterojunction was successfully formed between Co3O4 and TiO2 on the electrode, which inhibited the recombination of electrons and holes, and had a high photocurrent density. In our photoelectrocatalysis (PEC) degradation experiments, the degradation rates of bisphenol A (BPA) by Co3O4/TiO2-NRs electrode in Na2SO4 and simulated seawater system reached 69.44 and 100%, respectively. The important role of ·O2-, ·OH, h+, and active chlorine (Cl·, HClO/ClO-, and Cl2) on the Co3O4/TiO2-NRs electrode during the degradation of BPA in simulated seawater was revealed. In addition, PEC combined with electrokinetic (EK) studies with the Co3O4/TiO2-NRs electrode were used for the degradation of BPA in muddy water, initially expanding the application scope of the PEC performance of the Co3O4/TiO2-NRs electrode for pollutants degradation, and had great potential for the subsequent treatment of muddy water pollutants.

Terrace-Like 2D Hierarchically Porous Iron/Cobalt Metal-Organic Framework: Ambient Fast Synthesis and Efficient Oxygen Evolution Reaction Application

It is urgent to design a low-cost electrocatalyst with high activity to enhance the efficiency of oxygen evolution reaction (OER), which is limited by the slow four-electron transfer kinetics process. Nevertheless, traditional synthetic methods, including calcination and solvothermal, of the electrocatalysts are high-cost, low-yield, and energy-hogging, which limits their industrial application. Herein, an ambient fast synthetic method is developed to prepare terrace-like Fe/Co bimetal-organic framework (TFC-MOF) electrocatalyst materials in gram scale in 1 h. The method in this paper is designable based on coordination chemistry. Fe and Co ions can coordinate with the carboxyl groups on benzene-1,3,5-tricarboxylic acid (H3 BTC) to form a 2D-MOF structure. Structural characterizations, including SEM, TEM, and XRD are conducted to verify that the TFC-MOF is a terrace-like layered structure with uniform-sized mesoporous, which reduces the adsorption steric hindrance and facilitates the mass and electron transfer efficiency of OER. The TFC-MOF shows low overpotential, 255 mV at a current density of 10 mA cm-2 , and a low Tafel slope of 49.9 mV dec-1 , in an alkaline solution. This work provides a planar coordination strategy to synthesize 2D-MOF OER electrocatalyst on a large scale with low cost and low energy consumption, which will promote its practical OER applications.

Application of Fe-MOFs in Photodegradation and Removal of Air and Water Pollutants: A Review

Photocatalytic technology has received increasing attention in recent years. A pivotal facet of photocatalytic technology lies in the development of photocatalysts. Porous metal-organic framework (MOF) materials, distinguished by their unique properties and structural characteristics, have emerged as a focal point of research in the field, finding widespread application in the photo-treatment and conversion of various substances. Fe-based MOFs have attained particular prominence. This review explores recent advances in the photocatalytic degradation of aqueous and gaseous substances. Furthermore, it delves into the interaction between the active sites of Fe-MOFs and pollutants, offering deeper insights into their mechanism of action. Fe-MOFs, as photocatalysts, predominantly facilitate pollutant removal through redox processes, interaction with acid sites, the formation of complexes with composite metal elements, binding to unsaturated metal ligands (CUSs), and hydrogen bonding to modulate their respiratory behavior. This review also highlights the focal points of future research, elucidating the challenges and opportunities that lie ahead in harnessing the characteristics and advantages of Fe-MOF composite catalysts. In essence, this review provides a comprehensive summary of research progress on Fe-MOF-based catalysts, aiming to serve as a guiding reference for other catalytic processes.

Review: Synthesis of metal organic framework-based composites for application as immunosensors in food safety

Ensuring food safety continues to be one of the major global challenges. For effective food safety monitoring, fast, sensitive, portable, and efficient food safety detection strategies must be devised. Metal organic frameworks (MOFs) are porous crystalline materials that have attracted attention for use in high-performance sensors for food safety detection owing to their advantages such as high porosity, large specific surface area, adjustable structure, and easy surface functional modification. Immunoassay strategies based on antigen-antibody specific binding are one of the important means for accurate and rapid detection of trace contaminants in food. Emerging MOFs and their composites with excellent properties are being synthesized, providing new ideas for immunoassays. This article summarizes the synthesis strategies of MOFs and MOF-based composites and their applications in the immunoassays of food contaminants. The challenges and prospects of the preparation and immunoassay applications of MOF-based composites are also presented. The findings of this study will contribute to the development and application of novel MOF-based composites with excellent properties and provide insights into advanced and efficient strategies for developing immunoassays.

Constructing functional metal-organic frameworks by ligand design for environmental applications

Metal-organic frameworks (MOFs) with unique physical and chemical properties are composed of metal ions/clusters and organic ligands, including high porosity, large specific surface area, tunable structure and functionality, which have been widely used in chemical sensing, environmental remediation, and other fields. Organic ligands have a significant impact on the performance of MOFs. Selecting appropriate types, quantities and properties of ligands can well improve the overall performance of MOFs, which is one of the critical issues in the synthesis of MOFs. This article provides a comprehensive review of ligand design strategies for functional MOFs from the number of different types of organic ligands. Single-, dual- and multi-ligand design strategies are systematically presented. The latest advances of these functional MOFs in environmental applications, including pollutant sensing, pollutant separation, and pollutant degradation are further expounded. Furthermore, an outlook section of providing some insights on the future research problems and prospects of functional MOFs is highlighted with the purpose of conquering current restrictions by exploring more innovative approaches.

Plasma Meets MOFs: Synthesis, Modifications, and Functionalities

As a porous and network materials consisting of metals and organic ligands, metal-organic frameworks (MOFs) have become one of excellent crystalline porous materials and play an important role in the era about materials science. Plasma, as a useful tool for stimulating efficient reactions under many conditions, and the plasma-assisted technology gets more attractions and endows MOFs more properties. Based on its feature, the research about the modifications and functionalities of MOFs have been developing a certain extent. This review contains a description of the methods for plasma-assisted modification and synthesis of MOFs, with specifically focusing on the plasma-assisted potential for modifications and functionalities of MOFs. The different applications of plasma-assisted MOFs were also presented.