Recent advancements in modifications of metal-organic frameworks-based materials for enhanced water purification and contaminant detection.

Metal-organic frameworks (MOFs) have emerged as a key focus in water treatment and monitoring due to their unique structural features, including extensive surface area, customizable porosity, reversible adsorption, and high catalytic efficiency. While numerous reviews have discussed MOFs in environmental remediation, this review specifically addresses recent advancements in modifying MOFs to enhance their effectiveness in water purification and monitoring. It underscores their roles as adsorbents, photocatalysts, and in luminescent and electrochemical sensing. Advancements such as pore modification, defect engineering, and functionalization, combined synergistically with advanced materials, have led to the development of recyclable MOF-based nano-adsorbents, Z-scheme photocatalytic systems, nanocomposites, and hybrid materials. These innovations have broadened the spectrum of removable contaminants and improved material recyclability. Additionally, this review delves into the creation of multifunctional MOF materials, the development of robust MOF variants, and the simplification of synthesis methods, marking significant progress in MOF sensor technology. Furthermore, the review addresses current challenges in this field and proposes potential future research directions and practical applications. The growing research interest in MOFs underscores the need for an updated synthesis of knowledge in this area, focusing on both current challenges and future opportunities in water remediation.

MXene Hybrid Nanosheet of WS2/Ti3C2 for Electrocatalytic Hydrogen Evolution Reaction.

Designing low-cost hybrid electrocatalysts for hydrogen production is of significant importance. Recently, MXene-based materials are being increasingly employed in energy storage devices owing to their layered structure and high electrical conductivity. In this study, we propose a facile hydrothermal strategy for producing WS2/Ti3C2 nanosheets that function as electrocatalysts in the hydrogen evolution reaction (HER). WS2 provides a high surface area and active sites for electrocatalytic activity, whereas MXene Ti3C2 facilitates charge transfer. As a result, the synthesized WS2/Ti3C2 offers an increased surface area and exhibits an enhanced electrocatalytic activity in acidic media. The WS2/Ti3C2 (10%) catalyst exhibited a low onset potential of -150 mV versus RHE for the HER and a low Tafel slope of ∼62 mV dec-1. Moreover, WS2/Ti3C2 (10%) exhibited a double-layer capacitance of 1.2 mF/cm-2, which is 3 and 6 times greater than those of bare WS2 and Ti3C2, respectively. This catalyst also maintained a steady catalytic activity for the HER for over 1000 cycles.

Ni, Co, Zn, and Cu metal-organic framework-based nanomaterials for electrochemical reduction of CO2: A review.

The combustion of fossil fuels has resulted in the amplification of the greenhouse effect, primarily through the release of a substantial quantity of carbon dioxide into the atmosphere. The imperative pursuit of converting CO2 into valuable chemicals through electrochemical techniques has garnered significant attention. Metal-organic frameworks (MOFs) have occured as highly prospective materials for the reduction of CO2, owing to their exceptional attributes including extensive surface area, customizable architectures, pronounced porosity, abundant active sites, and well-distributed metallic nodes. This article commences by elucidating the mechanistic aspects of CO2 reduction, followed by a comprehensive exploration of diverse materials encompassing MOFs based on nickel, cobalt, zinc, and copper for efficient CO2 conversion. Finally, a meticulous discourse encompasses the challenges encountered and the prospects envisioned for the advancement of MOF-based nanomaterials in the realm of electrochemical reduction of CO2.

Metal-organic framework-based nanomaterials for CO2 storage: A review.

The increasing recognition of the impact of CO2 emissions as a global concern, directly linked to the rise in global temperature, has raised significant attention. Carbon capture and storage, particularly in association with adsorbents, has occurred as a pivotal approach to address this pressing issue. Large surface area, high porosity, and abundant adsorption sites make metal-organic frameworks (MOFs) promising contenders for CO2 uptake. This review commences by discussing recent advancements in MOFs with diverse adsorption sites, encompassing open metal sites and Lewis basic centers. Next, diverse strategies aimed at enhancing CO2 adsorption capabilities are presented, including pore size manipulation, post-synthetic modifications, and composite formation. Finally, the extant challenges and anticipated prospects pertaining to the development of MOF-based nanomaterials for CO2 storage are described.

Hollow Ni/NiO/C composite derived from metal-organic frameworks as a high-efficiency electrocatalyst for the hydrogen evolution reaction.

Metal-organic frameworks (MOFs) constitute a class of crystalline porous materials employed in storage and energy conversion applications. MOFs possess characteristics that render them ideal in the preparation of electrocatalysts, and exhibit excellent performance for the hydrogen evolution reaction (HER). Herein, H-Ni/NiO/C catalysts were synthesized from a Ni-based MOF hollow structure via a two-step process involving carbonization and oxidation. Interestingly, the performance of the H-Ni/NiO/C catalyst was superior to those of H-Ni/C, H-NiO/C, and NH-Ni/NiO/C catalysts for the HER. Notably, H-Ni/NiO/C exhibited the best electrocatalytic activity for the HER, with a low overpotential of 87 mV for 10 mA cm-2 and a Tafel slope of 91.7 mV dec-1. The high performance is ascribed to the synergistic effect of the metal/metal oxide and hollow architecture, which is favorable for breaking the H-OH bond, forming hydrogen atoms, and enabling charge transport. These results indicate that the employed approach is promising for fabricating cost-effective catalysts for hydrogen production in alkaline media.

A GO/CoMo3S13 chalcogel heterostructure with rich catalytic Mo-S-Co bridge sites for the hydrogen evolution reaction.

Molybdenum disulfide (MoS2)-based materials are extensively studied as promising hydrogen evolution reaction (HER) catalysts. In order to bring out the full potential of chalcogenide chemistry, precise control over the active sulfur sites and enhancement of electronic conductivity need to be achieved. This study develops a highly active HER catalyst with an optimized active site-controlled cobalt molybdenum sulfide (CoMo3S13) chalcogel/graphene oxide aerogel heterostructure. The highly active CoMo3S13 chalcogel catalyst was achieved by the synergetic catalytic sites of [Mo3S13]2- and the Mo-S-Co bridge. The optimized GO/CoMo3S13 chalcogel heterostructure catalyst exhibited high catalytic HER performance with an overvoltage of 130 mV, a current density of 10 mA cm-2, a small Tafel slope of 40.1 mV dec-1, and remarkable stability after 12 h of testing. This study presents a successful example of a synergistic heterostructure exploiting both the appealing electrical functionality of GO and catalytically active [Mo3S13]2- sites.

Flexible and high-sensitivity sensor based on Ti3C2-MoS2 MXene composite for the detection of toxic gases.

It is vital to have high sensitivity in gas sensors to allow the exact detection of dangerous gases in the air and at room temperature. In this study, we used 2D MXenes and MoS2 materials to create a Ti3C2-MoS2 composite with high metallic conductivity and a wholly functionalized surface for a significant signal. At room temperature, the Ti3C2-MoS2 composite demonstrated clear signals, cyclic response curves to NO2 gas, and gas concentration-dependent. The sensitivities of the standard Ti3C2-MoS2 (TM_2) composite (20 wt% MoS2) rose dramatically to 35.8%, 63.4%, and 72.5% when increasing NO2 concentrations to 10 ppm, 50 ppm, and 100 ppm, respectively. In addition, the composite showed reaction signals to additional hazardous gases, such as ammonia and methane. Our findings suggest that highly functionalized metallic sensing channels could be used to construct multigas-detecting sensors that are very sensitive in air and at room temperature.

Metal-Organic-Framework- and MXene-Based Taste Sensors and Glucose Detection.

Taste sensors can identify various tastes, including saltiness, bitterness, sweetness, sourness, and umami, and have been useful in the food and beverage industry. Metal-organic frameworks (MOFs) and MXenes have recently received considerable attention for the fabrication of high-performance biosensors owing to their large surface area, high ion transfer ability, adjustable chemical structure. Notably, MOFs with large surface areas, tunable chemical structures, and high stability have been explored in various applications, whereas MXenes with good conductivity, excellent ion-transport characteristics, and ease of modification have exhibited great potential in biochemical sensing. This review first outlines the importance of taste sensors, their operation mechanism, and measuring methods in sensing utilization. Then, recent studies focusing on MOFs and MXenes for the detection of different tastes are discussed. Finally, future directions for biomimetic tongues based on MOFs and MXenes are discussed.

WS2-WC-WO3 nano-hollow spheres as an efficient and durable catalyst for hydrogen evolution reaction.

Transition metal dichalcogenides (TMDs), transition metal carbides (TMCs), and transition metal oxides (TMOs) have been widely investigated for electrocatalytic applications owing to their abundant active sites, high stability, good conductivity, and various other fascinating properties. Therefore, the synthesis of composites of TMDs, TMCs, and TMOs is a new avenue for the preparation of efficient electrocatalysts. Herein, we propose a novel low-cost and facile method to prepare TMD-TMC-TMO nano-hollow spheres (WS2-WC-WO3 NH) as an efficient catalyst for the hydrogen evolution reaction (HER). The crystallinity, morphology, chemical bonding, and composition of the composite material were comprehensively investigated using X-ray diffraction, Raman spectroscopy, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. The results confirmed the successful synthesis of the WS2-WC-WO3 NH spheres. Interestingly, the presence of nitrogen significantly enhanced the electrical conductivity of the hybrid material, facilitating electron transfer during the catalytic process. As a result, the WS2-WC-WO3 NH hybrid exhibited better HER performance than the pure WS2 nanoflowers, which can be attributed to the synergistic effect of the W-S, W-C, and W-O bonding in the composite. Remarkably, the Tafel slope of the WS2-WC-WO3 NH spheres was 59 mV dec-1, which is significantly lower than that of the pure WS2 NFs (82 mV dec-1). The results also confirmed the unprecedented stability and superior electrocatalytic performance of the WS2-WC-WO3 NH spheres toward the HER, which opens new avenues for the preparation of low-cost and highly effective materials for energy conversion and storage applications.

Metal-Organic Framework Materials for Perovskite Solar Cells.

Metal-organic frameworks (MOFs) and MOF-derived materials have been used for several applications, such as hydrogen storage and separation, catalysis, and drug delivery, owing to them having a significantly large surface area and open pore structure. In recent years, MOFs have also been applied to thin-film solar cells, and attractive results have been obtained. In perovskite solar cells (PSCs), the MOF materials are used in the form of an additive for electron and hole transport layers, interlayer, and hybrid perovskite/MOF. MOFs have the potential to be used as a material for obtaining PSCs with high efficiency and stability. In this study, we briefly explain the synthesis of MOFs and the performance of organic and dye-sensitized solar cells with MOFs. Furthermore, we provide a detailed overview on the performance of the most recently reported PSCs using MOFs.

Design of Zeolite-Covalent Organic Frameworks for Methane Storage.

A new type of zeolite-based covalent organic frameworks (ZCOFs) was designed under different topologies and linkers. In this study, the silicon atoms in zeolite structures were replaced by carbon atoms in thiophene, furan, and pyrrole linkers. Through the adoption of this strategy, 300 ZCOFs structures were constructed and simulated. Overall, the specific surface area of ZCOFs is in the range of 300-3500 m2/g, whereas the pore size is distributed from 3 to 27 Å. Furthermore, the pore volume exhibits a wide range between 0.01 and 1.5 cm3/g. Screening 300 ZCOFs with the criteria towards methane storage, 11 preliminary structures were selected. In addition, the Grand Canonical Monte Carlo technique was utilized to evaluate the CH4 adsorption ability of ZCOFs in a pressure ranging from 1 to 85 bar at a temperature of 298 K. The result reveals that two ZCOF structures: JST-S 183 v/v (65-5.8 bar) and NPT-S 177 v/v (35-1 bar) are considered as potential adsorbents for methane storage. Furthermore, the thermodynamic stability of representative structures is also checked base on quantum mechanical calculations.