Benzene Tricarboxylate Research Articles

Enhanced detection of heavy metal ions using Ag nanoparticles and single-walled carbon nanotubes within Cu-based metal-organic frameworks

Heavy metal ions (HMIs) are major water pollutants, and their toxicity for humans is a great concern for scientists and environmentalists. They are harmful to health even at trace levels; therefore, identifying and removing heavy metals from water is critical. Herein, we report highly selective and sensitive multi-analyte detection of HMIs in water using an electrochemical sensor probe based on Ag nanoparticles and single-walled carbon nanotubes incorporating copper benzene tri-carboxylate metal–organic frameworks (Ag/SWNTs@CuBTC-MOFs). The materials were characterized using FTIR, XPS, XRD, and FE-SEM with EDX mapping, TEM, TG-DTA, BET surface area, CV, and EIS. The Ag/SWNTs@CuBTC-MOF electrochemical sensor was tested by differential pulse voltammetry over a pH range of 3–10 for various HMIs. It shows high pH-dependent sensitivity towards Hg2+ (pH-5.0), Ni2+ (pH-7.0), and Fe3+ (pH-10.0) ions and a limit of detection of 1.39 nM, 2.6 nM, and 3.03 nM, respectively. The fabricated sensor probe exhibits high selectivity, good linearity, and a limit of detection below the maximum contamination limit, as the US Environmental Protection Agency suggested.

A mixed-ligand Co metal-organic framework and its carbon composites as excellent electrocatalysts for the oxygen evolution reaction in green-energy devices.

Oxygen evolution reaction (OER) electrocatalysts are frequently made from noble metal-based oxides like ruthenium/iridium oxides. However, because of their scarcity and high price, researchers are now focusing on creating innovative OER catalysts based on affordable transition metals that have improved electrical conductivity and accessibility to active sites. Metal-organic frameworks (MOFs), a unique class of inorganic materials with excellent physical and chemical properties, have witnessed significant progress in promising green energy systems. In this work, a novel mixed-ligand metal-organic framework [Co(μ-1κN,2κN'-BDP)(μ3-1κoo',2κo''2κo'''-BTC)]n·nH2O (BDP = boron-dipyrromethene or BODIPY; BTC = benzene tricarboxylate) denoted as CoBDPMOF has been synthesized, and its composites with different carbon materials have been designed. Compared to the pristine MOF, the composites showed enhanced electrocatalytic activity toward the oxygen evolution reaction (OER) in alkaline media. In addition, the CoBDPMOF with activated carbon showed the highest OER performance with a low Tafel slope (82 mV dec-1) and the highest j600 (59.8 mA cm-2), outperforming noble metal IrO2, the OER benchmark electrocatalyst. This study presents new insights into the design and application of CoBDPMOF-based materials for energy conversion and suggests promising avenues for further research and development in electrocatalysis.

Unlocking the potential of phosphogypsum waste: Unified synthesis of functional metal-organic frameworks and zeolite via a sustainable valorization route

Phosphogypsum (PG) is one of the hazardous wastes generated during phosphate fertilizers production. Valorizing PG into value-added materials is needed to overcome the environmental threat of accumulating PG stockpiles. The primary chemical constituents of PG are CaSO4·2H2O, SiO2, Al2O3, P2O5, and trace metals. Herein, we employed unified strategic synthesis method to transform the main components of PG into two classes of functional porous materials in subsequent steps. The alumina and silica components were isolated to fabricate cancrinite zeolite (CAN) while the residual calcium was directed to grow Ca-based metal–organic frameworks (Ca-MOFs) in the subsequent step. The resulting zeolite with a Si/Al ratio of ∼2.2 showed enhanced CO2 capture property, which, in many respects, is better than those achieved by similar frameworks from other precursors. The unveiled MOF synthesis approach was proven to be adaptable, allowing the preparation of different Ca-MOFs from organic linkers of diverse connectivity, namely Ca-BDC, Ca-BTC, and Ca-TCPB (SBMOF-2), using the linear ditopic benzene dicarboxylate, the tritopic benzene tricarboxylate, and tetracarboxylate-based linkers, respectively. The successful assembly of the porous materials was confirmed using various characterization techniques, including XRD, SEM-EDX, FTIR, and TGA-MS. The porosity of the materials was also probed using N2 at 77 K, CO2 at different temperatures, and H2O at 298 K sorption analyses. The Ca-BTC MOF with the optimal pore aperture size (∼3.4 Å) shows a potential for water/alcohol separation with a steep and fast moisture adsorption profile and negligible alcohol uptake. The synthetic transformation approach presented in this work represents the first example of a valorization route to form extended porous structures from PG waste.

Single-Walled Carbon Nanotubes-Copper Metal-Organic Framework Composite for the Sensitive Detection of Lead Ions in Aqueous Solutions

Lead (Pb) is a hazardous heavy metal extensively employed in various industrial applications, often resulting in the presence of its ionic form (Pb2+) in water resources. Due to its profound toxicity to humans and the environment, the reliable detection and removal of Pb2+ ions from water are imperative. In this study, we have successfully synthesized a composite material consisting of single-walled carbon nanotubes (SWNTs) incorporated into a copper-based metal-organic framework (MOF) known as copper benzene tricarboxylate (CuBTC). This composite denoted as SWNTs@CuBTC, was synthesized via a solvothermal route. Comprehensive characterizations, including Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area analysis, and thermogravimetric analysis (TGA), were conducted to elucidate its structural and morphological properties. Electrochemical assessments, specifically cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were carried out to evaluate the electrochemical behaviour of the SWNTs@CuBTC composite. Subsequently, a sensor utilizing SWNTs@CuBTC was constructed by modifying glassy carbon electrodes (GCE) through a drop-casting technique. The sensing capabilities of this sensor were systematically examined using the differential pulse voltammetry (DPV) technique. Our sensor exhibited exceptional sensitivity towards Pb2+ ions, with a remarkable limit of detection (LOD) of 25 nM and a sensitivity of 0.1499 μA/nM, showcasing its potential for highly sensitive detection of Pb2+ ions in aqueous solutions.

Cobalt-H3BTC Metal Organic Framework-Based Electrochemical Nanosensor for Hydrogen Peroxide

Metal organic frameworks (MOFs) have found diverse applications in electrocatalysis and electrochemical sensing, owing to the presence of both metallic nodes and organic networks. Here, we electrosynthesized cobalt benzene tricarboxylate MOF inside an open carbon nanopipette (CNP) to produce a CNP-CoMOF nanoelectrode whose response is determined by Co(II)/Co(III) nodes attached to its porous nanostructure. Steady-state voltammograms of ferrocenemethanol at CNP-CoMOF nanoelectrodes exhibit a sigmoidal shape with a well-defined plateau current. A linear calibration curve obtained for the hydrogen peroxide oxidation suggests that CNP–CoMOF nanoelectrodes are potentially useful as nanosensors for peroxide free from interference of dissolved dioxygen.

Modeling of transition metals coordination polymers of benzene tricarboxylate and pyridyl oxime-based ligands for application as antibacterial agents

Theoretical simulation involving density functional theory (DFT) computation and molecular docking has been utilized to investigate in detailed the reactivity, stability, bond interactions, and the antibacterial potential of coordination polymers constructed with pyridyl oxime and benzene tricarboxylate linkers is based on the earlier experimental studies reported by Ioannis et al., Molecules, 26 (2), 491, 2021. Five (5) complexes: [Zn(BTC)2(PyOx)2] [Cu(BTC)2(PyOx)2], [Ni(BTC)2(PyOx)2], [Co(BTC)2(PyOx)2], [Fe(BTC)2(PyOx)2] were investigated and the DFT calculations was accomplished using a combined basis sets of 6-311++G (2d,2p) and LanL2DZ for the ligands and central metal ions respectively at the B3LYP functional. Structurally, all five complexes showed tetrahedral geometry after optimization due to the bulkiness of the linkers with excellent linearity in bond lengths. Based on quantum chemical simulations, [Ni(BTC)2(PyOx)2] was observed to be the most reactive complex with lower energy gap of 1.45 eV whereas Co(BTC)2(PyOx)2] was said to be the most stable complex with high energy gap of 7.19eV which is in tandem with results from the natural bond orbital analysis (NBO). The potency of all complexes in combating multidrug resistance pathogens were studied by molecular docking analysis, [Ni(BTC)2(PyOx)2] have the most favorable docking score of -9.2 kcal/mol and excellent hydrogen bond interaction. This result is also in good agreement with the quantum descriptors. Thus, [Ni(BTC)2(PyOx)2] exhibits potentials to combat multidrug resistance pathogens.

Direct detection of TNF-α by copper benzene tricarboxylate MOFs/gold nanoparticles modified electrochemical label-free immunosensor using FFT admittance voltammetry

A new simple label-free electrochemical immunosensor was designed for sensitive and selective determination of tumor necrosis factor-alpha (TNF-α), through gold nanoparticles (GNPs) incorporated copper benzene tricarboxylate metal organic frameworks (HKUST-1) modified gold electrode, where TNF-α specific monoclonal antibody was bonded to the electrode surface through shaped self-assembled monolayer (SAM) of mercapto compounds. The fabrication steps were monitored by field emission scanning electron microscopy (FE-SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimized experimental conditions, fast Fourier transform admittance voltammetry (FFTADV) used for TNF-α measurement. A wide linear range of current response towards the TNF-α concentration from 0.0005 to 50 ng/mL and LOD value of 0.15 pg/mL were achieved using FFTADV. The described immunosensor had adequate sensitivity and selectivity towards direct determination of TNF-α in complex biological matrix.

Mechanistic Investigations of Gas-Phase Catalytic Hydrogenation in Metal–Organic Frameworks: Cooperative Activity of the Metal and Linker Sites in CuxRh3–x(BTC)2

The CuxRh3–x(BTC)2 catalyst (abbreviated CuRhBTC, BTC3– = benzene tricarboxylate) provides excellent dispersion of active metal sites coupled with well-defined, robust structures for propylene hydrogenation reactions. This material therefore serves as a unique prototype for understanding catalytic activity in metal organic frameworks (MOFs). The mechanism of gas-phase hydrogenation at the bimetallic metal nodes of a MOF has been investigated in detail for the first time using in situ spectroscopy and diffraction experiments combined with density functional theory (DFT) calculations. The reaction occurs via a cooperative process in which the metal and linker sites play complementary roles; specifically, H2 is dissociated at a Rh2+ site with a missing Rh–O bond, while protonation of the decoordinated carboxylate linker stabilizes the active sites and promotes H2 dissociation. In situ X-ray diffraction experiments show that the crystalline structure of the MOF is retained under reaction conditions at 20–100 °C. In situ Raman spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments demonstrate that propylene adsorbs at both Rh2+ and Cu2+ sites via π bonding. Cu2+ is catalytically inactive, but at Rh2+ sites, a propyl intermediate is observed when H2 is introduced into the propylene feed. Furthermore, the appearance of the O–H stretch of COOH at ∼3690 cm–1 in the DRIFT spectra is characteristic of defects consisting of missing Rh–O bonds. These experimental results are in general agreement with a reaction mechanism proposed by DFT, in which the decoordinated carboxylate linker is protonated, and the active Rh2+ site remains available for readsorption of reactants in the subsequent catalytic cycle.

Metal‐Organic‐Framework‐Based Electrochemical Nanosensor for Hydrogen Peroxide

AbstractElectrochemical applications of metal organic frameworks (MOFs) are of considerable current interest. Due to the large surface area exposed to solution, MOFs are potentially useful electrode materials for sensing inner‐sphere analytes, such as reactive oxygen species. Herein, we electrodeposited copper benzene tricarboxylate MOF (HKUST‐1) into the cavity of an open carbon nanopipette (CNP) to produce a CNP‐MOF nanoelectrode. Unlike electronically conductive metal or carbon electrodes, the electrochemical response of CNP–MOFs relies on oxidation/reduction of Cu(I)/Cu(II) nodes in the porous nanostructure. Nevertheless, sigmoidal steady‐state voltammograms with a well‐defined plateau current have been recorded for simple redox mediators, for example, ferrocenemethanol. A linear calibration curve obtained for the hydrogen peroxide reduction suggests that CNP–MOFs can potentially be useful as nanosensors for peroxide.

A Tb-based-metal–organic framework prepared under ultrasound for detection of organic amines in aqueous solution through fluorescence quenching

A luminescent Tb–benzenetricarboxylate (BTC) metal–organic framework (MOF) was synthesized, ultrasonically, and used (without any functionalization) for selective detection of organic amines through fluorescence quenching of the Tb-metal. Several amines, with various basicity, such as ethylenediamine (ED), diethanolamine (DOA), diethylamine (DEA), triethylamine, pyridine, aniline, and pyrrole were chosen as representative analytes. The quenching efficiency of the amine solutions relied on the basicity of the analytes and steric hindrance between the analytes and MOF. A Tb–BTC MOF, synthesized using ultrasound irradiation, shows better results than MOF synthesized using conventional electrical or microwave heating, which might be the effect of a better dispersion of the MOF due to smaller particle size, higher analyte diffusivity, and higher defect-site contents. The change in the luminescence of the Tb–MOF was attributed to the interaction of amines with the Tb-metal ions of the MOF through coordination/complexation. By applying the luminescent Tb–MOF (prepared with ultrasound), aliphatic organic amines like ED, DOA, and DEA could be detected up to 100 μM and 2 μM, with naked eyes and fluorescence spectrophotometry, respectively. However, other chemicals, such as alcohol, ketone, hydrocarbon, and hydrogen peroxide did not quench appreciably the fluorescence of Tb–MOF, suggesting the possible selective detection of amines.

Electrocatalytic detection of l-cysteine using molybdenum POM doped-HKUST-1 metal organic frameworks

Glass carbon electrodes (GCE) were modified with metal organic frameworks (MOFs) containing molybdenum polyoxometallates (Mo POMs) in a copper benzene tricarboxylate framework (HKUST-1). The Mo POMs were introduced via one-pot synthesis (Mo2) and post-synthetic modification (Mo1) techniques. The electrode modifiers were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermal analysis. The modified electrodes’ oxidation capacity toward l-cysteine was studied. Mo POMs significantly improved electron transfer kinetics compared to the bare GCE. The best Mo POM doped electrode (Mo1-GCE) had a catalytic rate constant of 2.2 × 104 M−1 s−1 and a limit of detection of 3.07 × 10−7 M. Under the employed experimental conditions, the detection response for l-cysteine was very fast (within 0.1 s) for all the modified electrodes and selective toward l-cysteine in the presence of other amino acids.

Tetracyanoquinodimethane doped copper-organic framework electrode with excellent electrochemical performance for energy storage applications

Metal-organic frameworks (MOFs) are emerging as potential electrode materials for next-generation energy storage devices. Cu3(BTC)2 (BTC = benzene tricarboxylate), also known as HKUST-1, is one of the most widely studied MOFs. In the present work, TCNQ (tetracyanoquinodimethane) doped HKUST-1, has been demonstrated as an efficient energy storage electrode material. The infiltration of TCNQ in HKUST-1 has resulted in the synthesis of a high surface area electrode material with significant electrical conductivity. TCNQ@HKUST-1 based electrode has delivered a high specific capacity of 208.8 mAh/g (751 C/g) at a current density of 2 A/g. An all-solid-state symmetrical device has been assembled using a polymer gel electrolyte, which has delivered energy and power densities of 70.5 Wh/kg and 0.83 kW/kg, respectively. Also, the device showed a maximum energy efficiency of 58.6% along with a long cycle life of 96% over 5000 successive charging-discharging cycles. The present system has yielded superior energy storage performance than most of the earlier reported MOF based electrodes.

Two new metal-organic frameworks: Synthesis, characterization, gas adsorption and simulation

Two new Metal-organic frameworks, [Na1Ni3(µ3-OH)(µ5-BTC)(µ6-BTC)(H2O)3].4H2O (BTC = Benzene tri-carboxylate ion) (1) and [Na1Co3(µ3-OH)(µ5-BTC)(µ6-BTC)(H2O)3].4H2O (2) were synthesized under hydrothermal conditions and characterized by FT-IR, TGA, elemental analyses, single crystal and powder X-ray diffraction techniques. The porous structure of 1 and 2 were investigated by BET, crystal voids, topological analysis, gas adsorption and GCMC simulations. In the pressure range from 0.1 to 1.5 bar the adsorption selectivity of CO2 over CH4 at 273 K, 288 K and 298 K, is high in the activated MOFs. However, the adsorption selectivity reduces to 1.3 by increasing the pressure to 10 bar. GCMC simulations indicated probable interactions of CO2 around metal nodes and CH4 near the carboxylate groups. Experimental gas adsorption together with the GCMC simulation suggested 1 and 2 can be potential candidates for greenhouse gas capture or CO2/CH4 separation.

Analysis of Pristine and Tcnq-Loaded MOF FILMS By Contactless Microwave Dielectric Spectroscopy Technique

Metal-organic frameworks (MOFs) are porous and crystalline Coordination Network Compounds (CNCs), also referred to as porous coordination polymers (PCPs), which consist of inorganic metal (or metal/oxo) clusters connected by organic linkers. Surface Anchored Metal-organic-framework (SURMOF) films consist of quasi-liquid phase epitaxially grown highly ordered crystalline MOF films. For this study we used MOF Cu3(BTC)2 (BTC: benzene tricarboxylate) films, also known as HKUST-1 (Hong Kong University of Science and Technology-1), which were infiltrated with tetracyano-quinodimethane (TCNQ) guest molecules to modulate the charge transport characteristics. HKUST-1 MOF thin films have been grown using a liquid phase epitaxy (LPE) spray method in which the metal-containing solution [1 mmol Cu(OAc)2] and the linker solution [0.1 mmol BTC] are sprayed alternately on modified silicon substrates. Subsequently, the samples were immersed into an ethanoic TCNQ solution.We report on localized charge transfer processes at microwave frequencies of porous metal-organic framework (MOF) HKUST-1 Cu2(BTC)3 samples. As part of this study we will compare measurements done in the HKUST-1 pristine form of the material with open pores and HKUST-1, where the pores have been infiltrated with tetracyano-quinodimethane (TCNQ), resulting in a hybrid structure with enhanced electrical conductivity and a significant measurable effect in the microwave propagation characteristics [1]. We present data and analysis from an evaluation of pristine and loaded HKUST-1 SURMOF films using the contactless broadband microwave dielectric spectroscopy (BDS). The technique enables the accurate operando evaluation of the electrical and magnetic properties of materials without compromising the kinetic conditions of the experiment. The BDS method is uniquely suitable for investigating charge transfer reactions, regardless of the nature of the charge carriers, i.e., electrons and holes [2]. As such, these material state-sensitive parameters could be used to monitor charge transfer changes in the SURMOF and SURMOF-TCNQ hybrid analytes.[1] G. M. Espallargas and E. Coronado, “Magnetic functionalities in MOFs: from the framework to the pore”, Chem. Soc. Rev., 2018,47, 533, DOI: 10.1039/c7cs00653e[2] A. M. Wernbacher et al, Operando Electrical Conductivity and Complex Permittivity Study on Vanadia Oxidation Catalysts, J. Phys. Chem. C 2019, 123, 8005−8017, DOI: 10.1021/acs.jpcc.8b07417

Detection of Pb(II): Au Nanoparticle Incorporated CuBTC MOFs.

In the present investigation, copper benzene tricarboxylate metal organic frameworks (CuBTC MOF) and Au nanoparticle incorporated CuBTC MOF (Au@CuBTC) were synthesized by the conventional solvothermal method in a round bottom flask at 105°C and kept in an oil bath. The synthesized CuBTC MOF and Au@CuBTC MOFs were characterized by structure using X-ray diffraction (XRD) spectroscopic methods including Fourier Transform Infrared spectroscopy, Raman Spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and Energy dispersive spectroscopy (EDS). We also characterized them using morphological techniques such as Field emission scanning electron microscopy (FE-SEM), and electrochemical approaches that included cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). We examined thermal stability by thermogravimetric analysis (TG/DTA) and N2 adsorption—desorption isotherm by Brunauer-Emmett-Teller (BET) surface area method. Both materials were tested for the detection of lead (II) ions in aqueous media. Au nanoparticle incorporated CuBTC MOF showed great affinity and selectivity toward Pb2+ ions and achieved a lower detection limit (LOD) of 1 nM/L by differential pulse voltammetry (DPV) technique, which is far below than MCL for Pb2+ ions (0.03 μM/L) suggested by the United States (U.S.) Environmental Protection Agency (EPA) drinking water regulations.

Selective and sensitive detection of lead Pb(II) ions: Au/SWNT nanocomposite-embedded MOF-199

Metal organic frameworks (MOFs) are best known for their highly crystalline structures, ultrahigh porosity with considerable surface area and tunable physicochemical properties. The promising architecture of MOFs, where central metal atoms are surrounded by organic ligands secures their prominent candidature for advanced sensor technology. In this work, we have synthesized gold (Au) nanoparticles and single-walled carbon nanotube (SWNTs) nanocomposite-incorporated copper benzene tricarboxylate (MOF-199) MOF (Au/SWNTs@MOF-199) by solvothermal route. The synthesized Au/SWNTs@ MOF-199 has rigorously characterized with spectroscopic, morphological, structural, electrochemical, thermal, Brunauer–Emmett–Teller (BET) surface area using N2 adsorption isotherm methods. The proposed Au/SWNTs@MOF-199 nanocomposite exhibited excellent electrochemical characteristics and sensing performance towards Pb2+ ions. The calibration plot for the electrochemical response of Au/SWNTs@MOF-199 towards Pb2+ ions was recorded for the range of 0.1 mM–1 pM (R2 = 99.58)) with a limit of detection of 25 pM/L and a rapid response time of a few seconds with high sensitivity, selectivity, repeatability and reproducibility as determined by error bar diagram. These results indicate the significant potential of Au/SWNTs@MOF-199 nanocomposites as highly sensitive Pb2+ ion sensor.

Framework induced deformation modulates the photophysical properties of ZnTetra(4-pyridyl)porphyrin incorporated within a new metal organic framework, RWLAA-1

Porphyrin based metal organic frameworks (MOFs) have provided a broad platform through which a wide variety of light harvesting applications have been developed. Of particular interest within light harvesting MOFs containing porphyrin chromophores is the extent to which the both environment of the porphyrin and the porphyrin conformation modulate the photophysical properties. With this in mind, a new MOF (RWLAA-1) has been synthesized based on zinc cations linked by zinc(ii) tetra(4-pyridyl)porphyrin (ZnTPyP) and benzene tricarboxylate (H3BTC) linkers in which the porphyrin exhibits significant conformational distortions that have a profound effect on the photophysics of the material including bathochromic shifts in both the optical (Soret and visible bands) and emission bands, reduction in the energy separation between the Q(0,0) and Q(0,1) emission bands and shorter singlet and triplet state lifetimes. These effects are consistent with the porphyrin deformation resulting in changes in the porphyrin electronic structure and excited state conformational dynamics that alter the vibronic coupling between the excited states (S1 and T1) and the S0 ground state.

Field effect transistor based on proton conductive metal organic framework (CuBTC)

Metal organic frameworks (MOFs) are crystalline materials with ultrahigh porosity and tunable physico-chemical properties. But most MOFs are electrical insulators which restricts their use in electronic devices. In the present study, a field effect transistor (FET) based on a proton-conductive MOF was investigated. Imidazole was used as a proton conductor to increase the conductivity of the copper benzene tricarboxylate (CuBTC) MOF and, further, it was used to develop the FET. The CuBTC was synthesized using the traditional solvothermal method. The proton-conductive MOF was synthesized by post-modification of the CuBTC via the pore filling method using imidazole molecules, which achieved a proton conductivity of ~1.04 × 10−4 S cm−1 at 70 °C (anhydrous conditions). The proton conductive MOF was characterized by various techniques; spectroscopically by Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, x-ray absorption spectroscopy, energy dispersive spectroscopy, alternating current (a.c.) impedance spectroscopy; thermally using thermogravimetric analysis; structurally using powder x-ray diffraction; morphologically using field emission scanning electron microscopy; electrically by FETs.

Investigating metal-organic framework based on nickel (II) and benzene 1,3,5-tri carboxylic acid (H3BTC) as a new photocatalyst for degradation of 4-nitrophenol

ABSTRACTMetal-organic framework nickel (II) benzene tricarboxylate Ni3(BTC)2·12H2O (MOF-Ni) has been synthesised under solvothermal conditions and characterised by single crystal X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). The photocatalytic degradation of 4-nitrophenol (4-NP) using MOF-Ni under UV light irradiation was investigated and showed satisfactory results. A catalytic mechanism is proposed in terms of the HOMO-LUMO (highest occupied molecular orbital-lowest unoccupied molecular orbital) gap and the associated light-induced transition. The results showed that the studied MOF-based photocatalyst can be reused three to five times in the photocatalysis process and can degrade and mineralise 74% and 48% of 4-NP, respectively.

Electrochemically derived CuO nanorod from copper-based metal-organic framework for non-enzymatic detection of glucose

In this work, we fabricated a novel enzyme-free glucose sensor based on CuO nanorod, which was electrochemically derived from the copper-based metal-organic framework, Cu3(BTC)2 (BTC: benzene tricarboxylate). Repeated potential cycling successfully oxidized Cu3(BTC)2 to CuO, leaving residual carboxylate on the catalyst surface. The oxidation process was carefully investigated by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier-transform IR, and scanning electron microscopy. Cyclic voltammetry and chronoamperometry studies of the electrochemical oxidation of glucose on the CuO nanorod revealed excellent electrocatalytic performance with high sensitivity of 1523.5 μA mM−1 cm−2, linear response up to 1.25 mM, and detection limit of 1 μM. Compared with commercial CuO powder, the CuO nanorod showed much higher sensitivity because of its large surface area (60.2 m2 g−1). Moreover, it exhibited good selectivity to glucose over potential interfering compounds. These results suggest the potential application of the Cu3(BTC)2-derived CuO nanorod as a non-enzymatic glucose sensor.