Metal-organic Framework Nanosheets Research Articles

Bridging Nickel-MOF and Copper Single Atoms/Clusters with H-Substituted Graphdiyne for the Tandem Catalysis of Nitrate to Ammonia.

Interfacial engineering of synergistic catalysts is one of the keys to achieving multiple proton-coupled electron transfer processes in nitrate-to-ammonia conversion. Herein, by joining ultrathin nickel-based metal-organic framework (denoted Ni-MOF) nanosheets with few-layered hydrogen-substituted graphdiyne-supported copper single atoms and clusters (denoted HsGDY@Cu), a tandem catalyst of Ni-MOFs@HsGDY@Cu with dual-active interfaces was developed for the concerted catalysis of nitrate-to-ammonia. In such a system, the sandwiched HsGDY layer could serve as a bridge to connect the coordinated unsaturated Ni2+ sites with Cu single atoms/clusters in a limited range of 0 to 3.6 nm. From Ni2+ to Cu, via the hydrogen spillover process, the hydrogen radicals (H·) generated at the unsaturated Ni2+ sites could migrate across HsGDY to the Cu sites to participate in the transformation of *HNO3 to NH3. From Cu to Ni2+, bypassing the higher reaction energy for *HNO3 formation on the Ni2+ sites, the NO2- detached from the Cu sites could diffuse onto the unsaturated Ni2+ sites to form NH3 as well. The combined results make this hybrid a tandem catalyst with dual active sites for the catalysis of nitrate-to-ammonia conversion with improved Faradaic efficiency at lower overpotentials.

Sub-Nanometer Mono-Layered Metal-Organic Frameworks Nanosheets for Simulated Flue Gas Photoreduction.

The dilemma between the thickness and accessible active site triggers the design of porous crystalline materials with mono-layered structure for advanced photo-catalysis applications. Here, a kind of sub-nanometer mono-layered nanosheets (Co-MOF MNSs) through the exfoliation of specifically designed Co3 cluster-based metal-organic frameworks (MOFs) is reported. The sub-nanometer thickness and inherent light-sensitivity endow Co-MOF MNSs with fully exposed Janus Co3 sites that can selectively photo-reduce CO2 into formic acid under simulated flue gas. Notably, the production efficiency of formic acid by Co-MOF MNSs (0.85mmolg-1h-1) is ≈13 times higher than that of the bulk counterpart (0.065mmolg-1h-1) under a simulated flue gas atmosphere, which is the highest in reported works up to date. Theoretical calculations prove that the exposed Janus Co3 sites with simultaneously available sites possess higher activity when compared with single Co site, validating the importance of mono-layered nanosheet morphology. These results may facilitate the development of functional nanosheet materials for CO2 photo-reduction in potential flue gas treatment.

Ru-regulated electronic structure CoNi-MOF nanosheets advance water electrolysis kinetics in alkaline and seawater media

Herein, an ion-exchange strategy is utilized to greatly improve the kinetics of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) by Ru-modified CoNi- 1,3,5-Benzenetricarboxylic acid (BTC)-metal organic framework nanosheets (Ru@CoNi-MOF). Due to the higher Ni active sites and lower electron transfer impedance, Ru@CoNi-MOF catalyst requires the overpotential as low as 47 and 279 mV, at a current density of 10 mA/cm2 toward HER and OER, respectively. Significantly, the mass activity of Ru@CoNi-MOF for HER and OER are 25.9 and 10.6 mA mg−1, nearly 15.2 and 8.8 times higher than that of Ni-MOF. In addition, the electrolyzer of Ru@CoNi-MOF demonstrates exceptional electrolytic performance in both KOH and seawater environment, surpasses the commercial Pt/C||IrO2 couple. Theoretical calculations prove that introducing Ru atoms in - CoNi-MOF modulates the electronic structure of Ni, optimizes adsorption energy for H* and reduces energy barrier of metal organic frameworks (MOFs). This modification significantly improves the kinetic rate of the Ru@CoNi-MOF during water splitting. Certainly, this study highlights the utilization of MOF nanosheets as advanced HER/OER electrocatalysts with immense potential, and will paves a way to develop more efficient MOFs for catalytic applications.

Two-dimensional chiral metal-organic framework nanosheets L-hyp-Ni/Fe@SiO2 composite for HPLC separation

In this study, we have synthesised a chiral l-hyp-Ni/Fe@SiO2 composite as a chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) for the first time. This was achieved by coating two-dimensional (2D) chiral metal-organic framework nanosheets (MONs) l-hyp-Ni/Fe onto the surface of activated SiO2 microspheres using the “wrapped in net” method. The separation efficiency of the l-hyp-Ni/Fe chromatographic column was systematically evaluated in normal-phase HPLC (NP-HPLC) and reversed-phase HPLC (RP-HPLC) configurations, employing various racemates as analytes. The findings revealed that 16 chiral compounds were separated using NP-HPLC, and five were separated using RP-HPLC, encompassing alcohols, amines, ketones, esters, alkanes, ethers, amino acids and sulfoxides. Notably, the resolution (Rs) of nine chiral compounds exceeded 1.5, indicating baseline separation. Furthermore, the resolution performance of the l-hyp-Ni/Fe@SiO2-packed column was compared with that of Chiralpak AD-H. It was observed that certain enantiomers, which either could not be resolved or were inadequately separated on the Chiralpak AD-H column, attained separation on the 2D chiral MONs column. These findings suggest a complementary relationship between the two columns in racemate separation, with their combined application facilitating the resolution of a broader spectrum of chiral compounds. In addition, baseline separation was achieved for five positional isomers on the l-hyp-Ni/Fe@SiO2-packed column. The effects of the analyte mass and column temperature on the resolution were also examined. Moreover, during HPLC analysis, the l-hyp-Ni/Fe columns demonstrated commendable repeatability, stability and reproducibility in enantiomer separation. This research not only advances the utilisation of 2D chiral MONs as CSPs but also expands their applications in the separation sciences.

Retina‐Inspired Nanofluidic Membranes for Underwater Visual Imaging Based on Active Ion Transport

AbstractThrough evolution, biological organisms have developed ways to sense light using ion channels, which holds several advantages, such as energy efficiency and water resistance, over humanmade optoelectronic devices. Herein, a retina‐inspired nanofluidic system is presented with a Janus heterogeneous membrane (J‐HM), which can achieve underwater visual imaging through light‐driven active ion transport. The J‐HMs are obtained through sequentially assembled WS2, and a kind of metal–organic framework nanosheets via the reaction between 2,3,6,7,10,11‐hexahydroxytriphenylene hydrate (HHTP) and Cu2+ (Cu‐HHTP). Due to the formed intramembrane electric field caused by the efficient charge separation under illumination, a photovoltaic driving force is generated for active ion transport from Cu‐HHTP to WS2. Furthermore, the unidirectionally active ion transport can be enhanced by self‐diffusion under a concentration gradient. The J‐HM with a single‐pixel design shows a nearly linear response with light intensity and has enough resolution for basic object recognition as well as a long‐term memory after data processing using a defined pixelated matrix, which can pave an avenue for designing more intelligent sensing systems.

Colorimetric and SERS dual-mode detection of GSH in human serum based on AuNPs@Cu-porphyrin MOF nanozyme

BackgroundRapid and accurate detection of glutathione content in human blood plays an important role in real-time tracking of related diseases. Currently, surface-enhanced Raman scattering/spectroscopy (SERS) combined with nanozyme material has been proven to have excellent properties in the detection applications compared to many other methods because of it combines the advantages of trace detection capability of SERS and efficient catalytic activity of nanozymes. However, there are still existing problems in real sample detection, and to achieve quantitative detection is still challenging. ResultsIn this study, gold nanoparticles (AuNPs) were synthesized in situ on the surface of two-dimensional Cu-porphyrin metal-organic framework (MOF) nanosheets to produce the AuNPs@Cu-porphyrin MOF nanozyme, which exhibited both oxidase-like activity and SERS detection ability. On one hand, the intrinsic oxidase-like activity of the nanozyme could be inhibited due to the chelation of glutathione (GSH) and Cu, which thus led to the visual color change of the solution. On the other hand, the abundant Raman “hot spots” at the nanogap generated by Au NPs and the internal standard (IS) signal provided by Cu-meso-tetra (4-carboxyphenyl) porphine (Cu-TCPP) MOF improved the sensitivity and quantitative accuracy of detection. Significance and noveltyA dual-mode signal output sensor based on the nanozyme was thus established, which could be used in the trace detection of GSH. Such a dual-mode sensor possesses excellent detection performance, with the advantage of both wide detection range from 1 to 300 μM in the colorimetric detection mode and high sensitivity with LOD of 5 nM in the SERS detection mode, and can be applied to GSH detection in actual serum samples with reliable results.

2D Co-Based Metal–Organic Framework Nanosheets for the One-Pot Synthesis of Cyclic Carbonates from Olefins and CO2

2D Co-Based Metal–Organic Framework Nanosheets for the One-Pot Synthesis of Cyclic Carbonates from Olefins and CO₂

Crystal engineering of bimetallic cobalt-based metal–organic framework nanosheets for high-performance aqueous rechargeable cobalt-zinc batteries

Aqueous rechargeable Zn-based batteries (ARZBs) have attracted increasing attention as favorable candidates for energy storage systems due to their high security, environmental friendliness, and abundance of electrode materials. At present, the most widely reported materials used in cobalt-zinc (Co-Zn) batteries are cobalt-based oxides and their derivatives, however, they still exhibit low actual capacities and unsatisfactory cycle lives. Metal-organic frameworks (MOFs), as a new class of porous materials with high specific surface area and adjustable pore size, have attracted considerable attention in the field of energy storage. Currently, pristine MOFs have currently few applications in Co-Zn batteries, and their performance is not ideal. Herein, we report a series of two-dimensional (2D) bimetallic CoM-MOF (M = Ni, Mn, Mg and Cu) nanosheets based on trimesic acid (H3BTC) ligand as cathodes for alkaline Co-Zn batteries via a simple one-pot hydrothermal synthesis. Among the synthesized MOFs, the CoNi-MOF nanosheets have the best performance, exhibiting a high reversible capacity of 344 mA h g−1 and demonstrating a good cycling life with 90 % capacity retention at 20 A g−1 after 1500 cycles. The energy storage mechanism is studied through a series of ex-situ characterizations. This study is of great importance in advancing the application of 2D pristine MOFs for high-performance Co-Zn batteries.

Nanocluster/metal-organic framework nanosheet-based confined ECL enhancement biosensor for the extracellular vesicle detection

Gastric cancer (GC) was one of the most common cancers with high mortality. The detection of GC peritoneal metastasis had important significance. In this work, we have developed the novel electrochemiluminescence (ECL) biosensor to detect microRNA in GC extracellular vesicle (EV). Firstly, in situ growth of Cu nanocluster (Cu NC) on the metal-organic frameworks (MOFs) nanosheet was achieved successfully. Due to the confinement effect, Cu NCs in the porous structure of Zn MOF possessed the high quantum yield and good stability. Meanwhile, Zn MOF provided good electrochemical activity for the ECL reaction. Furthermore, the nanosized MOFs did not only act as sensing platform to load Cu NCs and link biomolecules, but also reduce steric hindrance effect for biomolecular recognition. Additionally, Au NPs/MXene and phospholipid layer were prepared and modified on the electrode, which can regulate electron transfer and improve the target recognition efficiency. The Cu NCs/Zn MOF nanosheet-based ECL sensor was employed to detect miRNA-421 from 1 fM to 1 nM with a detection limit of 0.5 fM. Finally, extracellular vesicles form clinic GC patient ascites were extracted and analyzed. The results showed that the constructed biosensor can be used for the GC peritoneal metastasis diagnosis.

Hydrogen-Bonded Metal-Organic Framework Nanosheet as a Proton Conducting Membrane for an H2 /O2 Fuel Cell.

Proton-conducting metal-organic frameworks (MOFs) have attracted attention as potential electrolytes for fuel cells. However, research progress in utilizing MOFs as electrolytes for fuel cells has been limited, mainly due to challenges associated with issues such as the fabrication of MOF membranes, and hydrogen crossover through the MOF's pores. Here, we report proton conductivity and fuel cell performance of a self-standing membrane prepared from of a bismuth subgallateMOF nanosheets with non-porous structure are reported. The fabricated MOF nanosheet membrane with no binding agent exhibitsed structural anisotropy. The proton conductivity in the membrane thickness direction (4.4×10-3 Scm-1 ) at 90°C and RH 100% is observed to be higher than that in the in-plane direction of the membrane (3.3×10-5 Scm-1 ). The open circuit voltage (OCV) of a fuel cell with ≈120µm proton conducting membrane is 1.0V. The non-porous nature of the MOF nanosheets contributes to the relatively high OCV. A fuel cell using ≈40µm membrane as proton conducting electrolyte records a maximum of 25mWcm-2 power density and a maximum of 109mAcm-2 current density with 0.91V OCV at 80°C in humid conditions.

Coordination Self-Assembled AuTPyP-Cu Metal-Organic Framework Nanosheets with pH/Ultrasound Dual-Responsiveness for Synergistically Triggering Cuproptosis-Augmented Chemotherapy.

Reactive oxygen species (ROS) mediated tumor cell death is a powerful anticancer strategy. Cuproptosis is a copper-dependent and ROS-mediated prospective tumor therapy strategy. However, the complex tumor microenvironment (TME), low tumor specificity, poor therapy efficiency, and lack of imaging capability impair the therapy output of current cuproptosis drugs. Herein, we designed a dual-responsive two-dimensional metal-organic framework (2D MOF) nanotheranostic via a coordination self-assembly strategy using Au(III) tetra-(4-pyridyl) porphine (AuTPyP) as the ligand and copper ions (Cu2+) as nodes. The dual-stimulus combined with the protonation of the pyridyl group in AuTPyP and deep-penetration ultrasound (US) together triggered the controlled release in an acidic TME. The ultrathin structure (3.0 nm) of nanotheranostics promoted the release process. The released Cu2+ was reduced to Cu+ by depleting the overexpressed glutathione (GSH) in the tumor, which not only activated the Ferredoxin 1 (FDX1)-mediated cuproptosis but also catalyzed the overexpressed hydrogen peroxide (H2O2) in the tumor into reactive oxygen species via Fenton-like reaction. Simultaneously, the released AuTPyP could specifically bind with thioredoxin reductase and activate the redox imbalance of tumor cells. These together selectively induced significant mitochondrial vacuoles and prominent tumor cell death but did not damage the normal cells. The fluorescence and magnetic resonance imaging (MRI) results verified this nanotheranostic could target the HeLa tumor to greatly promote the self-enhanced effect of chemotherapy/cuproptosis and tumor inhibition efficiency. The work helped to elucidate the controlled assembly of multiresponsive nanotheranostics and the high-specificity ROS regulation for application in anticancer therapy.

Exfoliation of Metal-Organic Frameworks to Give 2D MOF Nanosheets for the Electrocatalytic Oxygen Evolution Reaction.

The structure and properties of materials are determined by a diverse range of chemical bond formation and breaking mechanisms, which greatly motivates the development of selectively controlling the chemical bonds in order to achieve materials with specific characteristics. Here, an orientational intervening bond-breaking strategy is demonstrated for synthesizing ultrathin metal-organic framework (MOF) nanosheets through balancing the process of thermal decomposition and liquid nitrogen exfoliation. In such approach, proper thermal treatment can weaken the interlayer bond while maintaining the stability of the intralayer bond in the layered MOFs. And the following liquid nitrogen treatment results in significant deformation and stress in the layered MOFs' structure due to the instant temperature drop and drastic expansion of liquid N2, leading to the curling, detachment, and separation of the MOF layers. The produced MOF nanosheets with five cycles of treatment are primarily composed of nanosheets that are less than 10 nm in thickness. The MOF nanosheets exhibit enhanced catalytic performance in oxygen evolution reactions owing to the ultrathin thickness without capping agents which provide improved charge transfer efficiency and dense exposed active sites. This strategy underscores the significance of orientational intervention in chemical bonds to engineer innovative materials.

Exfoliation of Metal–Organic Frameworks to Give 2D MOF Nanosheets for the Electrocatalytic Oxygen Evolution Reaction

AbstractThe structure and properties of materials are determined by a diverse range of chemical bond formation and breaking mechanisms, which greatly motivates the development of selectively controlling the chemical bonds in order to achieve materials with specific characteristics. Here, an orientational intervening bond‐breaking strategy is demonstrated for synthesizing ultrathin metal–organic framework (MOF) nanosheets through balancing the process of thermal decomposition and liquid nitrogen exfoliation. In such approach, proper thermal treatment can weaken the interlayer bond while maintaining the stability of the intralayer bond in the layered MOFs. And the following liquid nitrogen treatment results in significant deformation and stress in the layered MOFs’ structure due to the instant temperature drop and drastic expansion of liquid N2, leading to the curling, detachment, and separation of the MOF layers. The produced MOF nanosheets with five cycles of treatment are primarily composed of nanosheets that are less than 10 nm in thickness. The MOF nanosheets exhibit enhanced catalytic performance in oxygen evolution reactions owing to the ultrathin thickness without capping agents which provide improved charge transfer efficiency and dense exposed active sites. This strategy underscores the significance of orientational intervention in chemical bonds to engineer innovative materials.

Highly efficient and selective capture of uranium from groundwater by using an ultrathin 2D MOF nanosheet with pocket-like cavities

Highly efficient and selective removal of uranium from aqueous media is crucial for the sustained development of nuclear energy. Herein, we utilized the intrinsic advantages of two-dimensional (2D) metal–organic frameworks (MOFs) and developed an ultrathin 2D MOF nanosheet with cavity structure. The preconcentration of the pocket-like cavities on the MOF nanosheet and sufficient interactions with the adsorption sites in the cavity structure realized highly efficient removal of uranium from water. Even in the low concentration range of 0.05–1 ppm, relatively high removal ratios and fast adsorption kinetics still can be achieved. Additionally, the MOF nanosheet exhibited extremely high anti-interference capability, which can efficiently reduce uranium pollution (0.05–1 ppm) in acid groundwater to the safe level (≤30 ppb) recommended by World Health Organization, and the removal performance was comparable to that in deionized water. The adsorption mechanism was thoroughly studied by Fourier transform infrared analysis, X-ray photoelectron spectroscopy, and density functional theory calculations, which revealed that the interactions between uranyl ions and the carboxylate groups dominated uranium adsorption, and the H-bonding interactions in the pocket-like cavities played an important role in uranium extraction.

Benzothiadiazole-functionalized Zr-MOF nanosheets enable visible-light mediated photocatalytic oxidation of sulfides in water

Ultrathin metal-organic frameworks (MOFs) nanosheets incorporating photochromic units are highly efficient heterogeneous photocatalysts, thanks to their highly exposed catalytic sites, short diffusion pathways, and efficient separation of photo-generated carriers. Herein, we report on the solvothermal synthesis of photoactive benzothiadiazole (BTz) functionalized Zr-MOF nanosheets (Zr-BTDB-NS), which are constructed from Zr12 nodes linked by nine BTDB2− (BTDB = 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoate) ligands. The Zr-BTDB-NS exhibited superior photocatalytic activity towards the aerobic oxidation of a broad range of sulfides to their corresponding sulfoxides under visible light irradiation in water at room temperature, even in a gram-scale. The Zr-BTDB-NS can be efficiently recycled and reused for seven cycles without a decrease in conversion or selectivity. Detailed mechanism studies revealed that the Zr-BTDB-NS generates singlet oxygen (1O2) and superoxide radical (O2–) reactive oxygen species under visible light irradiation, which are responsible for the oxidation of sulfides into their corresponding sulfoxides. The simplicity of the synthetic approach as well as the diversity of photoactive organic units hold great promise for designing ultrathin, water-stable, and photoactive Zr-MOF nanosheets. This work will also be of added value for selective photooxidation of sulfides under green and mild conditions.

In Situ Exfoliation Growth Strategy Realizing Controlled Synthesis of 3D to 2D MOF Materials as High-Performance Electrochemical Biosensors.

Two-dimensional (2D) metal-organic framework (MOF) nanosheets with large surface area, ultrathin thickness, and highly accessible active sites have attracted great research attention. Developing efficient approaches to realize the controllable synthesis of well-defined 2D MOFs with a specific composition and morphology is critical. However, it is still a significant challenge to construct thin and uniform 2D MOF nanosheets and resolve the reagglomeration as well as poor stability of target 2D MOF products. Here, an "in situ exfoliation growth" strategy is proposed, where a one-step synthetic process can realize the successful fabrication of PBA/MIL-53(NiFe)/NF nanosheets on the surface of nickel foam (NF) via in situ conversion and exfoliation growth strategies. The PBA/MIL-53(NiFe)/NF nanosheets combine the individual advantages of MOFs, Prussian blue analogues (PBAs), and 2D materials. As expected, the resulting PBA/MIL-53(NiFe)/NF as a glucose electrode exhibits an extremely high sensitivity of 25.74 mA mM-1 cm-2 in a very wide concentration range of 180 nM to 4.8 μM. The present exciting work provides a simple and effective strategy for the construction of high-performance nonenzymatic glucose electrochemical biosensors.

Self-supporting electrode incorporating active Co sites for ultrafast ammonia production from nitrate reduction

Electrocatalytic nitrate (NO3−) reduction reaction (NitRR) provides us a green solution to synthesize ammonia (NH3) and ease environmental problems. However, the development of robust electrodes with high NH3 yield rates and Faradaic efficiencies (FEs) is still challenging. Herein, we report a self-supporting electrode incorporating vertically aligned Co-based metal-organic framework (MOF) nanosheets (Co-NDC/NF), which facilitates electron and mass transfer for efficient NitRR to NH3 within a wide range of NO3− concentration (0.05−1.0 M). In 1.0 M KOH + 1.0 M KNO3 electrolytes, such Co-NDC/NF reaches a notable NH3 yield rate of 19,200 ug h−1 cm−2, a high FE of 93.9% and excellent electrochemical stability, which is superior to most electrocatalysts. A flow-through reactor with large-area Co-NDC/NF also achieves the continuous production of 1096 mg L−1 NH3 under an industrial current density. Furthermore, the rapid transformation of *NO2− to *NO and selective conversion of *NO to *NOH played critical roles in NitRR toward ultrafast NH3 production. Our research not only offers a facile fabrication procedure for high-performance electrode, but also gives new insights into the enhanced electron transfer and mass transport within MOF-based electrode in electrochemical reactions.

Surface Electronic Properties-Driven Electrocatalytic Nitrogen Reduction on Metal-Conjugated Porphyrin 2D-MOFs.

Two-dimensional (2D) metal organic framework (MOF) or metalloporphyrin nanosheets with a stable metal-N4 complex unit present the metal as a single-atom catalyst dispersed in the 2D porphyrin framework. First-principles calculations on the 3d-transition metals in M-TCPP are investigated in this study for their surface-dependent electronic properties including work function and d-band center. Crystal orbital Hamiltonian population (-pCOHP) analysis highlights a higher contribution of the bonding state in the M-N bond and antibonding state in the N-N bond to be essential for N-N bond activation. A linear relationship between ΔGmax and surface electronic properties, N-N bond strength, and Bader charge has been found to influence the rate-determining potential for nitrogen reduction reaction (NRR) in M-TCPP MOFs. 2D Ti-TCPP MOF, with a kinetic energy barrier of 1.43 eV in the final protonation step of enzymatic NRR, shows exclusive NRR selectivity over competing hydrogen reduction (HER) and nitrogenous compounds (NO and NO2). Thus, Ti-TCPP MOF with an NRR limiting potential of -0.35 V in water solvent is proposed as an attractive candidate for electrocatalytic NRR.

Graphene-modified MIL-125-NH2 mixed matrix membranes for efficient H2 and CH4 purification

This study investigates the performance of the mixed matrix membranes (MMMs) incorporating hybrid fillers of metal-organic framework (MIL-125-NH2) and graphene nanosheets (GNs) for enhanced methane (CH₄) and hydrogen (H₂) separation in the purification sector. The physico-chemical properties of the MMMs were evaluated by SEM, XRD, FTIR, AFM, TGA, DTG, and Brunauer-Emmett-Teller. The permeability and selectivity of the MMMs were determined using different single gases (CO2, N2, H2, and CH4) at various temperatures (20–60 °C). Optimization of fabrication parameters resulted in a significant improvement in porosity and roughness of the fabricated MMMs. The permeabilities of the MOF/PES membrane are 20.3 (CO2), 23.9 (N2), 32.2 (CH4), and 24.1 (H2) x 104 Barrer, while incorporating 0.05 wt% of GNs into the MOF/PES membrane improved the permeability by 36 % (CO2), 41 % (N2), 31 % (CH4), and 370 % (H2). In addition, the H2/CO2 and H2/N2 selectivities of the MMMs significantly increased up to 4 and 3.3, with an improvements of 236 % and 230 %, respectively, compared to the MOF/PES membrane. Furthermore, the CH4/CO2 and CH4/N2 selectivities of the MMMs decreased by 4 %. Therefore, a hybrid filler (10 wt % of MIL-125-NH2 and 0.05 wt % of GNs is highly recommended to improve the permeability and selectivity of the PES membrane, expanding its potential applications in CH4 and H2 purification.

Two-Dimensional Nickel Porphyrinic Metal-Organic Framework-Modified Electrode for Electrochemical Sensing.

Due to their highly exposed active sites and high aspect ratio caused by their substantial lateral dimension and thin thickness, two-dimensional (2D) metal-organic framework (MOF) nanosheets are currently considered a potential hybrid material for electrochemical sensing. Herein, we present a nickel-based porphyrinic MOF nanosheet as a versatile and robust platform with an enhanced electrochemical detection performance. It is important to note that the nickel porphyrin ligand reacted with Cu(NO3)2·3H2O in a solvothermal process, with polyvinylpyrrolidone (PVP) acting as the surfactant to control the anisotropic development of creating a 2D Cu-TCPP(Ni) MOF nanosheet structure. To realize the exceptional selectivity, sensitivity, and stability of the synthesized 2D Cu-TCPP(Ni) MOF nanosheet, a laser-induced graphene electrode was modified with the MOF nanosheet and employed as a sensor for the detection of p-nitrophenol (p-NP). With a detection range of 0.5-200 μM for differential pulse voltammetry (DPV) and 0.9-300 μM for cyclic voltammetry (CV), the proposed sensor demonstrated enhanced electrochemical performance, with the limit of detection (LOD) for DPV and CV as 0.1 and 0.3 μM, respectively. The outstanding outcome of the sensor is attributed to the 2D Cu-TCPP(Ni) MOF nanosheet's substantial active surface area, innate catalytic activity, and superior adsorption capacity. Furthermore, it is anticipated that the proposed electrode sensor will make it possible to create high-performance electrochemical sensors for environmental point-of-care testing since it successfully detected p-NP in real sample analysis.