Papers by Keyword: Metal-Organic Framework

Abstract: This research aims to synthesize and characterize Ni(II)-terephthalate-pyrazine complex and to determine the thermal stability and porosity profile of the synthesized compound. The Ni(II)-terephthalate-pyrazine was made by solvothermal reaction using dimethylformamide at 130 and 150 °C and in Ni(II):terephthalic-acid:pyrazine mol ratios of 1:1:2 and 1:1:4. The precipitated products were characterized by infrared spectroscopy, SEM, and powder-XRD in order to confirm the presence of both ligand in the synthesized compound. Meanwhile, the thermal stability and porosity profile of the synthesized compound were determined by DTA-TGA and surface area analysers, respectively. Experimental data shows that green pale powder was obtained from all reactions in considerably good yield, which is different from the dark green crystalline solid of Ni(II)-terephthalate. SEM image reveals that the product has a smooth-wavy surface morphology. Infrared spectra of the synthesized compound show peaks of functional groups of C=O, C–O, C=N, and C–N groups, which confirm the presence of both ligands. Powder XRD analysis suggests that the crystal system of the synthesized compound is different from that of the Ni(II)-terephthalate. Based on these analyses, the targeted Ni(II)-terephthalate-pyrazine is successfully obtained. Moreover, the synthesized compound has lower thermal stability than that of Ni(II)-terephthalate, while the BET calculation suggest that the synthesized compound has pore volume of 0.10-0.14 cm³/g, pore diameter of 8.1-10.65 nm and surface area of 24-30 (m²/g). This porosity profile suggest that the synthesized compound is open for further application, such as adsorption or photocatalysis.

Abstract: In this study, we focus on studying the application of methyl blue pigment treatment by Fe/M-MOF (Ni, Co) metal ion modified materials. The factors affecting the adsorption process such as time, initial concentration, pH, and adsorbent content were evaluated. The results showed that the adsorption capacity was highest in the following conditions: pH6, initial concentration 50 ppm, adsorbent content 0.1 g/L and time was 60 minutes. The kinetic data are suitable for Langmuir and Pseudo-second-order models.

Abstract: Carbon Dots (CDs) have gained the attention of many researchers since its discovery in 2004 due to their unique nanostructure and properties. These are very promising carbonaceous nanomaterials having wide range of applications in sensors, imaging, energy storage, nanomedicine, electrocatalysis and optoelectronics. CDs have shown excellent physical and chemical properties like, high crystallization, good dispersibility and photoluminescence. Besides, these are now known to have excellent biocompatibility, long-term chemical stability, cost-effectiveness and negligible toxicity. Due to favourable physical structure and chemical characteristics, these nanocarbon-based materials have drawn an interest as supercapacitor (SC) electrode materials, opening upnew opportunities to increase the energy density and lifespan of SCs. Thus, variety of quick and affordable methods i.e., the arc-discharge method, microwave pyrolysis, hydrothermal method, and electrochemical synthesis have been developed to synthesize this versatile nanomaterial. There are undoubtedly many methods for creating CDs that are effective and affordable, but due to the safety and simplicity of synthesis, CDs made from waste or using environmentally friendly methods have been innovated. In order to devise sustainable chemical strategies for CDs, green synthetic methodologies based on "top-down" and "bottom-up" strategies have been prioritised. This review summarizes numerous synthetic strategies and studies that are essential for the creation of environment friendly processes for CDs. The recent developments in the use of CDs for photoluminescence and supercapacitance have been highlighted providing a clear understanding of the new source of energy and optoelectronic materials with a futuristic perspective.

Abstract: In the present research work, carbon nanosphere (5 wt. %, 10 wt. % and 15 wt. %)/Zr- based metal organic frame works (CNS: Zr (II)-MOFs) with different molar ratios of the legend 4-{[(1E)-1-Hydroxy-3-Oxoprop-1-En-2-yl] Sulfanyl} Benzoic Acid (HOSBA) have been successfully synthesized by hydrothermal method. Studies using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) have validated certain structural, optical, and morphological features. The supercapacitance performance of the synthesized MOFs was investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). At a current density of 0.5 A g^-1 and at a scan rate of 10 mV/s, the 15% CNS doped Zr-MOF demonstrated highest specific capacitance (C_s) of 239.4 F g^-1. 15 wt.% CNS doped Zr-MOF proven power density of 2100 W kg^-1 and maximum energy density of 14.82 Wh Kg^-1 with capacitive retention of 77.63 % following 2000 cycles mark this combination a good for supercapacitors (SCs) material. Regardless of the synthetic conditions, we achieved MOFs which exhibited hetero structure formation with spherical morphologies. The results open us new and energy approach for the supercapacitor of the Zr-metal based MOFs and applications in the photonics, optoelectronics, and promising electrode material for electrochemical energy storage systems.

Abstract: An electrical insulator known as a dielectric material is a substance that can be solid, liquid, or gaseous. Having a high specific resistance, a dielectric material is a non-metallic substance. A dielectric function as the perfect capacitor, storing and dissipating electrical energy. Due to the rising need for capacitors, semiconductor devices, Liquid Crystal Displays, electrical transformers, and other products, properties including electric susceptibility, dielectric polarisation, dispersion, relaxation, and tunability have received a great deal of attention. Advanced materials must be developed in order to further enhance their performance. Metal-organic frameworks (MOFs), a class of porous crystalline solids, have shown to be ideal models for synthesising functional materials that may be used to make supercapacitor electrodes. Greater electrical conductivity, a higher charge capacity, and variable electrochemical activity are just a few benefits that bimetallic MOFs and their derivatives have over monometallic MOFs. This study focuses on the usage of MOF-derived bimetallic in dielectric materials, with particular attention paid to understanding the cause of the enhanced performance and covering the most recent advancements in the area with a variety of applications.

Abstract: Lithium metal batteries (LMBs) possess large application potential for advanced rechargeable batteries due to the high energy density (> 500 Wh kg⁻¹) and alternative cathode materials. Random Li dendrite growth caused by uneven Li⁺ distribution and local ion depletion near surface of Li anode induces battery failure with inferior long-term stability. Therefore, regulation of ion distribution near anode surface is essential to realize dendrite-free and uniform Li deposition. Herein, a metal-organic framework (MOF), i.e., ZIF-8, is applied to regulate Li⁺ solvation structure via unsaturated metal-ion sites to achieve uniform Li⁺ distribution and Li deposition. A stable cycling performance over 800 h for Li symmetrical cell at 3 mA cm⁻² and 3 mAh cm⁻² without short circuit is realized. The facilitated Li⁺ solvation via the adsorption effect of metal-ion sites on anions is demonstrated, which further enhances the uniform Li⁺ distribution near Li anode surface. This work demonstrates an effective strategy for regulating ion coordination and Li⁺ distribution to stabilize Li anode via MOF-based materials.

Abstract: Red blood cells (RBCs) naturally delivery oxygen and kill pathogens through reactive oxygen species (ROS) generated from Fe-protoporphyrin component in hemoglobin, which might be also promising for cancer treatment in terms of relieving tumor hypoxia and inducing oxidative damage against cancer cells. However, the therapy efficacy is far from satisfactory due to the limited oxygen transport and ROS generation rate in tumor tissue. Herein, artificial RBCs (designated as FTP@RBCM) with radical storm production ability is developed for oncotherapy through multi-dimensional reactivity pathways of Fe-protoporphyrin based hybrid metal-organic framework (FTP, as the core), including photodynamic/chemodynamic (PDT/CDT)-like, catalase-like and glutathione (GSH) peroxidase-like activity. Meanwhile, owing to the advantages of reticuloendothelial system (RES) evasion and long circulation abilities of RBCs governed by their cell membranes (RBCMs), FTP with surface further coated with RBCMs (FTP@RBCM) could enormously accumulate at tumor site to achieve remarkably enhanced therapy efficiency.

Abstract: Polyvinylidene fluoride (PVDF) membranes, enhanced with metal-organic framework (MOF), were fabricated on a non-woven polyethylene terephthalate (PET) support using the non-solvent induced phase inversion (NIPS) method to produce mixed matrix membrane (MMM). Polymer concentration of 10%, 15%, and 20% were used in the study whereas UiO-66(Zr) was used as a MOF filler. The resulting membranes were characterized in terms of their morphology, porosity, wettability, mechanical strength, pure water flux, and gas permeability. Results show that the presence of UiO-66(Zr) filler improved membrane morphology, mechanical strength, and hydrophobicity of MMM as compared to pristine PVDF.

Abstract: Metal-organic frameworks (MOFs) are promising materials for a number of applications including gas storage and separation. In this work, coordination polymers based on copper and trimesic acid were prepared and characterized by physicochemical methods. Three different synthesis strategies were employed: precipitation at room temperature, hydrothermal method (at different temperatures) and using CO2 as SAS technique (Supercritical AntiSolvent). The obtaining samples was also tested on its capacity in CH4 adsorption at 1 bar and 296 К and 233K.

Abstract: This study explored the application of MOF-modified membrane for gas separation. Microporous aluminum fumarate (A520) was used to modify polyimide (PI) membrane using N-methylpyrrolidone (NMP) as solvent. The MOF-modified mixed matrix membrane (MMM) was subjected to gas permeability tests, using gas permeability apparatus (GPA). GPA results showed that adding 10wt% MOF to the membrane increased permeabilities of N₂ and CO₂ gases by up to 34%, and by 19% for O₂ gas, without compromising selectivity. Further increasing MOF loading beyond 10wt% considerably decreased selectivities despite significantly increased permeabilities. Cahn adsorption experiment confirmed and supported this GPA data. These results indicate that MOF were successfully intercalated with the polymer as revealed by scanning electron microscope (SEM) images. Other characterizations like dynamic mechanical analysis (DMA), x-ray diffraction (XRD), and positron annihilation lifetime spectroscopy (PALS) showed that the interface and mechanical properties of the MMM also improved. MOF loading beyond 10wt% revealed aggregations forming non-selective voids that probably caused lowered selectivity.