Cerium Metal Organic Framework Research Articles

Fluorescent Tetraphenylethylene-Based Cerium Metal-Organic Frameworks for White-Light-Emitting Diodes.

Discovery of highly efficient and thermal stable phosphors is the focus of the studies in phosphor-converted white light-emitting diodes (LEDs). Herein, a tetraphenylethylene-based cerium metal-organic framework (SYNU-2) was synthesized and characterized. The intricate architecture of SYNU-2 shows an overall 3D → 3D 2-fold interpenetration framework. SYNU-2 exhibited good luminescence properties, and its latent fingerprint developer was prepared, which showed good fluorescence and stability under ultraviolet (UV) radiation. It is worth noting that a prototype WLED device can be designed using SYNU-2 and red phosphors (Ca,Sr)AlSiN3:Eu2+ with CIE coordinates of (0.33, 0.33) at an applied 3 V bias.

Synergy in action: MOF-derived CoFeO3/Ce-MOF nanocomposites as piezo-photocatalysts for sustainable chromium reduction and nitrogen fixation

Piezo-photocatalysis, by enhancing the separation and migration of photoelectrons and holes, has garnered growing attention among researchers. Combining MOFs with CoFeO3, a recognized efficient piezo-catalyst, enhances the photocatalytic efficacy for reducing pollutants and stabilizing nitrogen compounds. In this study, we developed a series of CoFeO3/Ce-MOF nanocomposites by combining Cerium metal-organic frameworks with MOF-derived CoFeO3. To gauge their effectiveness, the CoFeO3/Ce-UiO-66, CoFeO3/Ce-MOF-808, and CoFeO3/Ce-MOF-801 heterostructures were assessed by employing multiple characterization methods including PXRD, FTIR, FESEM, TEM, DRS, EDX, VSM, PL, PC, EIS, Zeta, and BET. Generally, among the different nanocomposites studied, CoFeO3/Ce-MOF-801 achieved a remarkable result an outstanding 100 % efficiency in reducing Cr(VI) within just 30 minutes in pH=1, and in ammonia generation, with a rate of 292.13 μmol g−1 h−1L−1. The results indicate that CoFeO3/Ce-MOFs have the potential to be an eco-friendly and affordable MOF-based piezo-photocatalyst that can effectively tackle the challenges of traditional photocatalysts.

A non-enzymatic hydrogen peroxide biosensor based on cerium metal-organic frameworks, hemin, and graphene oxide composite

This study presents the development of a novel non-enzymatic electrochemical biosensor for the real-time detection of hydrogen peroxide (H2O2) based on a composite of cerium metal–organic frameworks (Ce-MOFs), hemin, and graphene oxide (GO). The Ce-MOFs served as an efficient matrix for hemin encapsulation, while GO enhanced the conductivity of the composite. Characterization techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, UV–vis spectroscopy, and thermogravimetric analysis (TGA) confirmed the successful integration of hemin into the Ce-MOFs. The Ce-MOFs@hemin/GO-modified sensor demonstrated sensitive H2O2 detection due to the exceptional electrocatalytic activity of Ce-MOFs@hemin and the high conductivity of GO. This biosensor exhibited a linear response to H2O2 concentrations from 0.05 to 10 mM with a limit of detection (LOD) of 9.3 μM. The capability of the biosensor to detect H2O2 released from human prostate carcinoma cells was demonstrated, highlighting its potential for real-time monitoring of cellular oxidative stress in complex biological environments. To further assess its practical applicability, the sensor was tested in human serum samples, yielding promising results with recovery values ranging from 94.50 % to 103.29 %. In addition, the sensor showed excellent selectivity against common interfering compounds due to the outstanding peroxidase-like activity of the composite.

Copper/ cerium metal organic frame work as highly efficient structures for solar power-induced hydrogen generation through the process of water splitting

Increased dependence on fossil fuels as energy sources strongly contributes in both global warming and environmental pollution, leading to serious impacts on human-beings and societies. Therefore, shift from hydrocarbon-based energy to alternative green, sustainable and renewable sources of energy has been globally stimulated in past decades. In an agreement with this context, hydrogen is counted as one of these sources which has been paid strong attention recently due to its high energy content and no harmful emissions. Consequently, this study introduces production of clean green hydrogen through the process of photocatalytic water splitting which is a cost-effective route and releases zero emissions. A series of copper/ or cerium based metal–organic frameworks were successfully prepared via one-pot solvothermal technique and were presented as three novel photocatalysts for hydrogen production from water. The photocatalytic performances of these structures were investigated under visible light irradiation, revealing the highest activity for copper doped cerium metal–organic framework. It exhibited a maximum pure hydrogen productivity of 465 mmol per hour/ gram which was much higher than those the detected productivity by copper and cerium metal–organic frameworks (289 and 375 mmol per hour/ gram respectively). Heterojunction between the two central metals as well as effective charge separation in copper doped cerium metal–organic framework are reasons of its superiority in hydrogen evolution exploit, compared to the other two structures. The recyclability of copper doped cerium metal–organic framework demonstrated high reliability since it showed nearly stable yields of hydrogen over ten cycles of photocatalytic reuse. Therefore, the presented binary metals organic framework establishes new platform for photocatalysts in process of hydrogen production through water splitting.

In-situ activation of biomimetic single-site bioorthogonal nanozyme for tumor-specific combination therapy

Copper-catalyzed click chemistry offers creative strategies for activation of therapeutics without disrupting biological processes. Despite tremendous efforts, current copper catalysts face fundamental challenges in achieving high efficiency, atom economy, and tissue-specific selectivity. Herein, we develop a facile “mix-and-match synthetic strategy” to fabricate a biomimetic single-site copper-bipyridine-based cerium metal-organic framework (Cu/Ce-MOF@M) for efficient and tumor cell-specific bioorthogonal catalysis. This elegant methodology achieves isolated single-Cu-site within the MOF architecture, resulting in exceptionally high catalytic performance. Cu/Ce-MOF@M favors a 32.1-fold higher catalytic activity than the widely used MOF-supported copper nanoparticles at single-particle level, as first evidenced by single-molecule fluorescence microscopy. Furthermore, with cancer cell-membrane camouflage, Cu/Ce-MOF@M demonstrates preferential tropism for its parent cells. Simultaneously, the single-site CuII species within Cu/Ce-MOF@M are reduced by upregulated glutathione in cancerous cells to CuI for catalyzing the click reaction, enabling homotypic cancer cell-activated in situ drug synthesis. Additionally, Cu/Ce-MOF@M exhibits oxidase and peroxidase mimicking activities, further enhancing catalytic cancer therapy. This study guides the reasonable design of highly active heterogeneous transition-metal catalysts for targeted bioorthogonal reactions.

Post-modification engineering of cerium metal-organic frameworks for efficient visible light-driven water oxidation

Post-modification engineering of cerium metal-organic frameworks for efficient visible light-driven water oxidation

Physisorption or chemisorption: Insight from AI computing model based on DFT, MC/MD-simulation for prediction of MOF-based inhibitor adsorption on Cu in brine solution

This study investigates the dynamics of cerium metal organic framework (Ce-MOF) adsorption on the Cu surface in brine solution. This research integrates computational modelling based on Density Functional Theory (DFT), Monte Carlo (MC), and Molecular Dynamics (MD) simulations for enhanced predictive modelling. Additionally, by the utilization of the Dmol3 module within Biovia materials studio software, DFT calculations /geometric configurations through the Double Numerical plus d-functions (DND) were achieved. Notably, the results demonstrate a robust negative adsorption energy (−363.54 kcal/mol), indicating a highly stable interaction leading to the formation of a protective film on the metal surface. The study also proposes a corrosion inhibition mechanism involving physical and chemical barriers. The findings not only contribute to fundamental corrosion science but also propose innovative strategies for designing MOF-based inhibitors tailored to specific environmental conditions. This research introduces a novel perspective by combining theoretical calculations, and simulation models for predicting inhibitor behavior, fostering advancements in corrosion protection strategies.

MOF-derived multi-"hotspot" 3D Au/MOF-808 (Zr) nanostructures as SERS substrates for the ultrasensitive determination of thiram.

Aconvenient self-assembly methodis proposed for synthesis of 3D Au/MOF-808 (Zr) composite nanostructures with a cerium metal-organic framework loaded with gold nanoparticles. We combine adsorption properties of MOF materials with surface plasmon resonance of noble metals to construct hotspot-dense 3D Au/MOF-808 (Zr) SERS substrates, by using a two-step method of solvothermal and reduction reactions. The results show that optimal SERS substrates are obtained from a volume ratio of gold nanoparticles to MOF-808 (Zr) solution of 4:1 and a self-assembly time of 2h. Rhodamine 6G (R6G) is used as a molecular probe to characterize and analyze SERS properties of substrates of 3D Au/MOF-808 (Zr) prepared under the optimal process conditions, where the substrates are capable to detect R6G concentrations down to 10-10 M with a relative standard deviation of 8.81%. Finally, we applied the SERS substrates of 3D Au/MOF-808 (Zr) to the detection of pesticide thiram, and establish a quantitative determination method. 3D Au/MOF-808 (Zr) provides a sensitive detection of thiram in lake water by SERS with a detection limit of 1.49 × 10-9 M. Application tests show that a SERS enhancement factor of the MOF-based SERS substrates for the detection of thiram can be significantly increased to 5.91 × 105. Thus, the above results indicate that such substrate has high sensitivity, good adsorption, homogeneity, and reproducibility, which can be extended for sensitive detection of pesticide residues in food and environment.

Enhancing the Green Synthesis of Glycerol Carbonate: Carboxylation of Glycerol with CO2 Catalyzed by Metal Nanoparticles Encapsulated in Cerium Metal-Organic Frameworks.

The reaction of glycerol with CO2 to produce glycerol carbonate was performed successfully in the presence of gold nanoparticles (AuNPs) supported by a metal-organic framework (MOF) constructed from mixed carboxylate (terephthalic acid and 1,3,5-benzenetricarboxylic acid). The most efficient were two AuNPs@MOF catalysts prepared from pre-synthesized MOF impregnated with Au3+ salt and subsequently reduced to AuNPs using H2 (catalyst 4%Au(H2)@MOF1) or reduced with NaBH4 (catalyst 4%Au@PEI-MOF1). Compared to existing catalysts, AuNPs@MOFs require simple preparation and operate under mild and sustainable conditions, i.e., a much lower temperature and the lowest CO2 overpressure ever reported, with MgCO3 having been found to be the optimal dehydrating agent. Although the yield of the process is still not competitive with previously developed systems, the most promising advantage is the highest TOF (78 h-1) ever reported for this reaction. The optimal parameters observed for AuNPs were also tested on AgNPs and CuNPs with promising results, suggesting their great potential for industrial application. The catalysts were characterized by XRD, TEM, SEM-EDS, ICP-MS, XPS, and porosity measurements, confirming that AuNPs are present in low concentration, uniformly distributed, and confined to the cavities of the MOF.

Cerium metal–organic framework composited with polyaniline on carbon cloth for high-sensitively electrochemical sensing of carbendazim

Carbendazim (CBZ) has generated significant attention due to potential harm to human health, thus developing a simple and economy-friendly approach for determining CBZ is vital. Herein, Cerium metal–organic framework (Ce-MOF) and polyaniline (PANI) were composited under mild condition and modified on carbon cloth (CC) to fabricate an electrochemical sensor based on Ce-MOF@PANI/CC for fast and sensitive determination of CBZ. Rod-shaped Ce-MOF facilitated the dispersion of PANI, while the doping of PANI improved conductivity of Ce-MOF to amplify detection signal. Moreover, the modification of Ce-MOF@PANI on CC increased the electrochemical active area of CC by 2.78 times. Under optimized conditions, the method demonstrated a linear range of 0.1–80 μM and a detection limit of 12.6 nM. Additionally, the response value of the sensor to CBZ still maintained 94.32 % of the initial value after 15 days. It also had good reproducibility and anti-interference. The sensor was utilized for detecting CBZ in fruit (apple, pear), vegetables (tomato, cucumber), and water (lake, tap water) with recovery of 92.31 %–105.47 % consistent with those of high-performance liquid chromatography.

Aggregation-induced enhancement of pyrene-based metal-organic framework as a new electrochemiluminescence emitter for ultrasensitive detection of sulfadimethoxine

In this study, a signal-on electrochemiluminescence (ECL) aptasensor for ultrasensitive detection of sulfadimethoxine (SDM) was constructed based on a competitive aptamer strategy. Specifically, cerium-metal-organic framework (Ce-MOF) with large specific surface area and excellent electrical conductivity was combined with gold nanoparticles (AuNPs) to form a substrate, followed by the immobilisation of double-stranded DNA (dsDNA) via AuN bonds. In the presence of SDM, the aptamer tended to form an aptamer-SDM complex, which caused dsDNA to dissociate. After release of the aptamer, the capture probe (CP) combined with the tracer label to enhance the ECL signal. As expected, the prepared sensor displayed an ideal linear response range from 10.0 fg mL−1 to 100 ng mL−1 with a limit of detection (LOD) of 1.28 fg mL−1 and successfully detected SDM in milk and quality control samples.

An ultrasensitive ratiometric electrochemical aptasensor based on metal-organic frameworks and nanoflower-like Bi2CuO4 for human epidermal growth factor receptor 2 detection

An ultra-sensitive ratiometric electrochemical aptasensor was constructed based on metal-organic frameworks (MOFs) and bimetallic oxides for the detection of the human epidermal growth factor receptor 2 (HER2), a breast cancer marker. The aluminum metal-organic framework (Al-MOF) and cerium-metal-organic framework (Ce-MOF) have higher specific surface area, which is conducive to load more aptamers or complementary DNA (cDNA), and realize the amplification of internal reference signal Fc. Furthermore, nanoflower-like bismuth copper oxide (Bi2CuO4) with abundant active sites was introduced to modify more aptamers on its surface, which were then fixed to the glassy carbon electrode (GCE) to amplify the detection signal. The quantitative detection of HER2 was achieved by differential pulse voltammetry (DPV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The materials were characterized by scanning electron microscope, transmission electron microscope, Zeta potential analyzer, X-ray diffraction and X-ray photoelectron spectroscopy. The ratiometric electrochemical aptasensor based on nanomaterial and chain displacement signal amplification technology could discern HER2 in a very wide range (0.001–20.0 ng/mL) with an extremely low detection limit (0.049 pg/mL) and has demonstrated good performance in clinical serum analysis. This strategy also provides a feasible idea for sensitive analysis of other clinical tumor markers.

A nanoplatform-based aptasensor to electrochemically detect epinephrine produced by living cells.

Anovel aptasensor has beendesigned for quantitative monitoring of epinephrine (EP) based on cerium metal-organic framework (CeMOF) loaded gold nanoparticles (AuNPs). The aptamer, specific to EP, is immobilized on a flexible screen-printed electrode modified with AuNPs@CeMOF, enabling highly selective binding to the target biomolecule. Under optimized operational conditions, the peak currents using voltammetric detectionmeasured at voltage of 83mV (vs. Ag/AgCl) for epinephrine exhibit a linear increase within concentration in the range1pM-10nM. Following this detection strategy, a boasted limit of detection of 0.3pM was achieved, surpassing the sensitivity of most reported methods. The developed biosensor showcased exceptional performance in detection ofEP in spiked serum sample, with remarkable recovery range of 95.8-113% and precision reflected by low relative standard deviation (RSD) ranging from 2.23 to 6.19%. These results indicate the potential utility of this biosensor as a valuable clinical diagnostic tool. Furthermore, in vitro experiments were carried out using the presented biosensor to monitor the release of epinephrine from PC12 cells upon extracellular stimulation with K+ ions.

A luminous strategy for the recognition of toxic antibiotics in water via efficient energy transfer

Fluoroquinolones (FQs) are the class of Antibiotics (ABs) that have been extensively used worldwide for the treatment of diseases caused by bacterial infections. In India, most of these untreated ABs and their unused metabolites present in treated and untreated wastewater end up in agricultural land and water bodies. This can accelerate the problem of antimicrobial resistance in the community. Hence, we aim to develop a cost-effective sensor to detect and monitor the presence of such drugs in water bodies. We have prepared a chemically reduced graphene oxide (rGO) integrated luminescent cerium metal-organic framework (MOF) that specifically targets and recognizes ciprofloxacin (CPFX), norfloxacin (NFX), and ofloxacin (OFX) achieving excellent sensing activity. A remarkable quenching of the fluorescence of MOF composite was observed upon interaction with CPFX, NFX, and OFX with 57.9, 46.3, and 51.6 ppb as limits of detection, respectively, through a Forster resonance energy transfer from the Ce-MOF to the analytes. The applicability of the sensor was also examined with real-time samples collected from the rivers of Chennai city and the MOF probe exhibited an appreciable recovery of results. This is the first study on Ce-MOF-based rGO composite providing a solid rationale for fluorescence detection of FQs with exceptional quenching efficiency and very high sensitivity for monitoring FQs in water bodies even in diluted conditions.

Spherically Structured Ce‐Metal‐Organic Frameworks with Rough Surfaces and Carbon‐Coated Cerium Oxide as Potential Electrodes for Lithium Storage and Supercapacitors

AbstractThe rough spherical‐shaped cerium metal‐organic framework (Ce‐MOF) is synthesized by using solvothermal technique, and after being calcined at 550 °C both with and without tannic acid, CeO2 and C@CeO2 are produced. As synthesized Ce‐MOF, CeO2, and C@CeO2 are constructed as anodes for lithium‐ion batteries (LIBs), also Ce‐MOF and C@CeO2 are investigated for use in supercapacitors. In the case of LIBs, as anode, C@CeO2 exhibits a good reversible discharge capacity of 137 mAh g−1 with 99 % coulombic efficiency over 250 cycles at 1 C rate. It demonstrates that the conductivity is greatly improved by the carbon covering than the pristine CeO2 and Ce‐MOF. After the galvanostatic charge‐ discharge technique at 1 C rate, the morphology size was investigated using FESEM to conform further the following alloying and dealloying mechanism of C@CeO2 and the dissolution of terephthalic acid (TPA) in the non‐aqueous electrolyte that is connected to the core structure of Ce‐MOF. In terms of supercapacitors, rough surface morphology improves the electrode electrolyte conduct also the ligand TPA of free terminal acid group attracting K+ and forms the COO− K+. Thus, Ce‐MOF exhibits a good specific capacitance; after 5000 cycles, it produces 118 F g−1 at 4 A g−1.with 65.2 % capacitance retention. The archived maximum power and energy density outcomes of 10.6 kW kg−1 and 0.56 Wh kg−1 at 2 A g−1.

Selective Methane Oxidation to Acetic Acid Using Molecular Oxygen over a Mono-Copper Hydroxyl Catalyst.

Acetic acid is an industrially important chemical, produced mainly via carbonylation of methanol using precious metal-based homogeneous catalysts. As a low-cost feedstock, methane is commercially transformed to acetic acid via a multistep process involving energy-intensive methane steam reforming, methanol synthesis, and, subsequently, methanol carbonylation. Here, we report a direct single-step conversion of methane to acetic acid using molecular oxygen (O2) as the oxidant under mild conditions over a mono-copper hydroxyl site confined in a porous cerium metal-organic framework (MOF), Ce-UiO-Cu(OH). The Ce-UiO MOF-supported single-site copper hydroxyl catalyst gave exceptionally high acetic acid productivity of 335 mmolgcat-1 in 96% selectivity with a Cu TON up to 400 at 115 °C in water. Our spectroscopic and theoretical studies and controlled experiments reveal that the conversion of methane to acetic acid occurs via oxidative carbonylation, where methane is first activated at the copper hydroxyl site via σ-bond metathesis to afford Cu-methyl species, followed by carbonylation with in situ-generated carbon monoxide and subsequent hydrolysis by water. This work may guide the rational design of heterogeneous abundant metal catalysts for the activation and conversion of methane to acetic acid and other valuable chemicals under mild and environmentally friendly reaction conditions.

A metabolic intervention strategy to break evolutionary adaptability of tumor for reinforced immunotherapy.

The typical hallmark of tumor evolution is metabolic dysregulation. In addition to secreting immunoregulatory metabolites, tumor cells and various immune cells display different metabolic pathways and plasticity. Harnessing the metabolic differences to reduce the tumor and immunosuppressive cells while enhancing the activity of positive immunoregulatory cells is a promising strategy. We develop a nanoplatform (CLCeMOF) based on cerium metal-organic framework (CeMOF) by lactate oxidase (LOX) modification and glutaminase inhibitor (CB839) loading. The cascade catalytic reactions induced by CLCeMOF generate reactive oxygen species "storm" to elicit immune responses. Meanwhile, LOX-mediated metabolite lactate exhaustion relieves the immunosuppressive tumor microenvironment, preparing the ground for intracellular regulation. Most noticeably, the immunometabolic checkpoint blockade therapy, as a result of glutamine antagonism, is exploited for overall cell mobilization. It is found that CLCeMOF inhibited glutamine metabolism-dependent cells (tumor cells, immunosuppressive cells, etc.), increased infiltration of dendritic cells, and especially reprogrammed CD8+ T lymphocytes with considerable metabolic flexibility toward a highly activated, long-lived, and memory-like phenotype. Such an idea intervenes both metabolite (lactate) and cellular metabolic pathway, which essentially alters overall cell fates toward the desired situation. Collectively, the metabolic intervention strategy is bound to break the evolutionary adaptability of tumors for reinforced immunotherapy.

Ce-MOF-based superhydrophobic polyurethane sponge reinforced by cellulose for efficient oil-water separation

It is extremely significant to manufacture materials with simple and low-cost synthetic method for the disposal of large-scale oil spills and environmental pollution caused by the illegal discharge of oily wastewater. In this paper, cerium metal-organic framework (Ce-MOF), 1H, 1H, 2H, 2H perfluorodecyltrimethoxysilane (PFOTS) and cellulose were used as raw materials to prepare polyurethane hydrophobic sponges (PU) interconnected by chemical bonds to improve physical properties performance. The sponge shows excellent superhydrophobicity with a surface water contact angle (WCA) of 152.53 ± 0.8°. It has high mechanical strength and oil absorption capacity for various oils/organic solvents up to 15.0–44.9 times its weight. It is more imortant that C–F–Ce@PU can separate immiscible oil-water mixtures driven by vacuum pump or gravity. Superhydrophobic/oleophilic C–F–Ce@PU can also be used to separate water-in-oil emulsions. The above characteristics provide a reference for its practical application in oil-water separation.

Fenton-like Cerium Metal–Organic Frameworks (Ce-MOFs) for Catalytic Oxidation of Olefins, Alcohol, and Dyes Degradation

AbstractA metal–organic framework (MOF) of cerium (Ce) ions and 4,4′,4′′-nitrilotribenzoic acid linker was synthesized via a hydrothermal method. Ce-MOF consists of a Lewis acid moiety, i.e. Ce3+ and triphenylamine cores. It showed Fenton-like properties with excellent catalytic oxidation activity for olefins, primary/secondary alcohols, and water pollutants e.g., organic dyes. It displayed high oxidation conversion of cinnamyl alcohol and styrene of 100% and 53%, respectively. It offered good selectivity towards styrene oxide and benzaldehyde (i.e. 75% and 100%, respectively). It was applied for the oxidative degradation of dyes e.g. rhodamine B (RhB), methyl blue (MeB), Congo red (CR), and direct blue (DB) using hydrogen peroxide (H2O2) as an oxidant. It exhibited high efficiency in the oxidative degradation of these water pollutants. The mechanistic study of oxidation involves the formation of radical hydroxyl (•OH) species. This study revealed the possibility of enhancing the oxidative catalytic performance, including oxidative degradation of organic pollutants, by employing advanced oxidation processes (AOPs) using Ce-MOF. The catalyst is recyclable five times without significantly decreasing of the material’s catalytic performance.

Au and Pt Nanoparticles Grown on Flexible Carbon Fiber Cloth Supports Decorated with Cerium Metal Organic Frameworks for the Real-Time Detection of H2O2 in Live Cancer Tissue

Au and Pt Nanoparticles Grown on Flexible Carbon Fiber Cloth Supports Decorated with Cerium Metal Organic Frameworks for the Real-Time Detection of H₂O₂ in Live Cancer Tissue