Facile synthesis of a three-dimensional Ln-MOF@FCNT composite for the fabrication of a symmetric supercapacitor device with ultra-high energy density: overcoming the energy storage barrier

In order to quench the thirst for efficient energy storage devices, a novel praseodymium-based state-of-the-art three-dimensional metal-organic framework (MOF), {[Pr(pdc)2]Me2NH2}n (YK-1), has been synthesized by using a simple solvothermal method employing a readily available ligand. YK-1 was characterised by single-crystal XRD and crystallographic analysis. The electrochemical measurements of YK-1 show that it exhibits a specific capacitance of 363.5 F g-1 at a current density of 1.5 A g-1 with 83.8% retention after 5000 cycles. In order to enhance its electrochemical performance for practical application, two composites of YK-1 with graphene oxide (GO) and functionalised multi-walled carbon nanotubes (FCNTs), namely YK-1@GO and YK-1@FCNT, were fabricated by employing a facile ultrasonication technique. The as-synthesized MOF and the composites were characterized by PXRD, FTIR, SEM, and TEM techniques. YK-1@GO and YK-1@FCNT offer enhanced specific capacitances of 488.2 F g-1 and 730.2 F g-1 at the same current density with 93.8% and 97.7% capacity retention after 5000 cycles, respectively (at 16 A g-1). Fascinated by the outstanding results shown by YK-1@FCNT, a symmetric supercapacitor device (SSC) based on it was fabricated. The assembled SSC achieved a remarkable energy density (87.6 W h kg-1) and power density (750.2 W kg-1) at a current density of 1 A g-1, along with very good cycling stability of 91.4% even after 5000 GCD cycles. The SSC device was able to power up several LED lights and even operated a DC brushless fan for a significant amount of time. To the best of our knowledge, the assembled SSC device exhibits the highest energy density among the MOF composite-based SSCs reported so far.

Designing 3D Ternary Hybrid Composites Composed of Graphene, Biochar and Manganese Dioxide as High-Performance Supercapacitor Electrodes

Biochar derived from waste biomass has proven to be an encouraging novel electrode material in supercapacitors. In this work, luffa sponge-derived activated carbon with a special structure is produced through carbonization and KOH activation. The reduced graphene oxide (rGO) and manganese dioxide (MnO₂) are in-situ synthesized on luffa-activated carbon (LAC) to improve the supercapacitive behavior. The structure and morphology of LAC, LAC-rGO and LAC-rGO-MnO₂ are characterized by the employment of X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), BET analysis, Raman spectroscopy and scanning electron microscopy (SEM). The electrochemical performance of electrodes is performed in two and three-electrode systems. In the asymmetrical two-electrode system, the LAC-rGO-MnO₂//Co₃O₄-rGO device shows high specific capacitance (SC), high-rate capability and excellent cycle reversibly in a wide potential window of 0-1.8 V. The maximum specific capacitance (SC) of the asymmetric device is 586 F g^-1 at a scan rate of 2 mV s^-1. More importantly, the LAC-rGO-MnO₂//Co₃O₄-rGO device exhibits a specific energy of 31.4 W h kg^-1 at a specific power of 400 W kg^-1. Overall, the synergistic effect between the ternary structures of microporous LAC, rGO sheets and MnO₂ nanoparticles leads to the introduction of high-performance hierarchical supercapacitor electrodes.

Metal-Organic Framework Materials for Electrochemical Supercapacitors

Exploring new materials with high stability and capacity is full of challenges in sustainable energy conversion and storage systems. Metal-organic frameworks (MOFs), as a new type of porous material, show the advantages of large specific surface area, high porosity, low density, and adjustable pore size, exhibiting a broad application prospect in the field of electrocatalytic reactions, batteries, particularly in the field of supercapacitors. This comprehensive review outlines the recent progress in synthetic methods and electrochemical performances of MOF materials, as well as their applications in supercapacitors. Additionally, the superiorities of MOFs-related materials are highlighted, while major challenges or opportunities for future research on them for electrochemical supercapacitors have been discussed and displayed, along with extensive experimental experiences.

BioMOF-Mn: An Antimicrobial Agent and an Efficient Nanocatalyst for Domino One-Pot Preparation of Xanthene Derivatives

In this paper, a new Mn-based metal-organic framework [UoB-6] was obtained via a one-step ultrasonic irradiation method with the ligand (H₂bdda: 4,4'-(1,4-phenylenebis(azaneylylidene))bis(methaneylylidene))dibenzoic acid. The structural integrity of the synthesized BioMOF-Mn was corroborated by FT-IR, EDX, ICP, XRD, TEM, DLS, FESEM, and BET-BJH analyses. The aerobic oxidative domino reaction of benzyl alcohols or aldehydes with dimedone derivatives was performed in the presence of the UoB-6 catalyst to produce xanthene derivatives in good yields. Hot filtration and Hg poisoning tests proved the heterogeneous nature of the catalyst. Novel synthesized xanthene-based bis-aldehydes were introduced as potent HDAC1 inhibitors according to molecular docking calculations. Finally, the inhibitory activities of Mn-MOF nanoparticles were evaluated on Escherichia coli and Candida albicans. The MIC, MBC, and MFC values were determined from 2048 to 4096 μg·mL^-1 according to antimicrobial susceptibility testing methods. The inhibitory effects of antimicrobial agents can be exacerbated when loaded on BioMOFs.

A new visual and stable fluorescent Cu-MOF as a dual-function sensor for glyphosate and Cr2O72−

A new visual and stable Cu-MOF as a dual-function sensor with high sensitivity for the detection of glyphosate and Cr2O72−.

Europium oxide nanorod-reduced graphene oxide nanocomposites towards supercapacitors

Fast charge/discharge cycles are necessary for supercapacitors applied in vehicles including, buses, cars and elevators. Nanocomposites of graphene oxide with lanthanide oxides show better supercapacitive performance in comparison to any of them alone. Herein, Eu₂O₃ nanorods (EuNRs) were prepared through the hydrothermal method and anchored onto the surface of reduced graphene oxide (RGO) by utilizing a sonochemical procedure (in an ultrasonic bath) through a self-assembly methodology. The morphologies of EuNRs and EuNR-RGO were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and IR spectroscopy. Then, we used EuNRs and EuNR-RGO as electrode materials to investigate their supercapacitive behavior using cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy techniques. In a 3.0 M KCl electrolyte and with a scan rate of 2 mV s⁻¹, EuNR-RGO exhibited a specific capacity of 403 F g⁻¹. Galvanostatic charge–discharge experiments demonstrated a specific capacity of 345.9 F g⁻¹ at a current density of 2 A g⁻¹. The synergy between RGO's flexibility and EuNR's high charge mobility caused these noticeable properties.

Fast charge/discharge cycles are necessary for supercapacitors applied in vehicles including, buses, cars and elevators.

Terbium metal–organic frameworks as capable electrodes for supercapacitors

Tb-MOF as electrode material for supercapacitors with high specific capacitance and excellent capacitance retention.

The preparation and characterization of UiO-66 metal–organic frameworks for the delivery of the drug ciprofloxacin and an evaluation of their antibacterial activities

In recent years, metal–organic frameworks have been extensively used as drug carriers due to their benefits.