Cerium-based Metal-organic Framework Research Articles

Construction of trifunctional electrode material based on Pt-Coordinated Ce-Based metal organic framework

The main challenge hindering the use of Pt nanoparticles (Pt NPs) for electrochemical applications is their high cost and agglomeration. Herein, a trifunctional electrode material based on a two-dimensional cerium-based metal organic framework (2D Ce-MOF) decorated with Pt NPs is constructed. The large specific surface area of the 2D Ce-MOF can effectively prevent the phenomenon of Pt NPs reaction. The strong synergy between Pt NPs and the 2D Ce-MOF not only significantly enhances electron transport efficiency, but also increases the number of electrochemically reaction reactive sites. As a result, the Ce-MOF@Pt presents excellent performance in the HER (Hydrogen Evolution Reaction), OER (Oxygen Evolution Reaction) and supercapacitor reactions. The Tafel slopes of OER and HER are 47.9 and 188.1 mV dec-1, respectively. Meanwhile, Ce-MOF@Pt-0.05 shows a specific capacity of 1894F g−1 at a current density of 1 A g−1 and remains at 111.5% of the initial capacitance after 3000 cycles. In general, this study highlights the importance of Pt NPs in promoting the electrochemical performance of MOFs and reveals a new way to reduce electrocatalyst prices.

Arylation of C(sp3)–H Bonds with a Cerium-Based Metal–Organic Framework Catalyst

Arylation of C(sp3)–H Bonds with a Cerium-Based Metal–Organic Framework Catalyst

Catalytic ozonation of Acetaminophen with a magnetic, Cerium-based Metal-Organic framework as a novel, easily-separable nanocomposite

A novel Fe3O4@Ce-UiO-66 composite was prepared and tested in the catalytic ozonation of Acetaminophen (ACT) in aqueous solution under various experimental conditions. The Fe3O4@Ce-UiO-66 dramatically increased ACT degradation and mineralization in the catalytic ozonation process (COP); ACT degradation led to 14.1% total organic carbon (TOC) reduction by single ozonation process at pH 7 within 10 min, while in the presence of Fe3O4@Ce-UiO-66, 90.2% TOC was removed in the COP. It was shown that HO∙ was the main species improving ACT degradation and proved the effective catalyzing role of the synthesized MOF on the ozonation process enhancement. The catalyst was efficiently separated magnetically from the treated suspension and was stable, as well as reusable, for multiple cycles. Furthermore, the ACT degradation intermediates were identified utilizing LC-MS, from which the probable transformation pathways were suggested. In overall, this work offers deep insights into the potential of MOFs for accelerating the ozonation-mediated removal process of emerging contaminants in water treatment.

One-Step MOF-Templated Strategy to Fabrication of Ce-Doped ZnIn2 S4 Tetrakaidecahedron Hollow Nanocages as an Efficient Photocatalyst for Hydrogen Evolution.

Achieving structure optimizing and component regulation simultaneously in the ZnIn2S4‐based photocatalytic system is an enormous challenge in improving its hydrogen evolution performance. 3D hollow‐structured photocatalysts have been intensively studied due to their obvious advantages in solar energy conversion reactions. The synthesis of 3D hollow‐structured ZnIn2S4, however, is limited by the lack of suitable template or synthesis methods, thereby restricting the wide application of ZnIn2S4 in the field of photocatalysis. Herein, Ce‐doped ZnIn2S4 photocatalysts with hollow nanocages are obtained via one‐step hydrothermal method with an ordered large‐pore tetrakaidecahedron cerium‐based metal–organic frameworks (Ce‐MOFs) as template and Ce ion source. The doping of Ce and the formation of ZnIn2S4 tetrakaidecahedron hollow nanocages with ultrathin nanosheet subunits are simultaneously induced by the Ce‐MOFs, making this groundbreaking work. The Ce‐doped ZnIn2S4 with a nonspherical 3D hollow nanostructure inherit the tetrakaidecahedron shape of the Ce‐MOF templates, and the shell is composed of ultrathin nanosheet subunits. Both theoretical and experimental results indicate that the doping of Ce and the formation of hollow nanocages increase light capture and the separation of photogenerated charge carriers.

Cerium-based metal–organic framework as an electrocatalyst for the reductive detection of dopamine

Thin films of a chemically stable and electrochemically active cerium(IV)-based metal–organic framework (MOF), Ce-MOF-808, are capable of electrocatalyzing the reduction of dopaquinone (DAQ) generated by the electrochemical pre-oxidation of dopamine (DA) present in 3-(N-morpholino)propanesulfonic acid buffer solutions. As the first study reporting the use of pristine cerium-based MOFs in electrochemical DA detection, the stability of the MOF during electrochemical operations, optimized thin-film loading, and the electrocatalytic mechanism are investigated. By utilizing the cathodic Faradaic responses for the reduction of the electrochemically pre-generated DAQ as a probe to detect DA in the electrolyte, the interference signals from the commonly coexisting ascorbic acid and uric acid can be effectively reduced.

In Situ Embedding Synthesis of CsPbBr3@Ce-MOF@SiO2 Nanocomposites for High Efficiency Light-Emitting Diodes: Suppressing Reabsorption Losses through the Waveguiding Effect.

All-inorganic perovskite quantum dots (PQDs), which possess outstanding photophysical properties, are regarded as promising materials for optoelectronic applications. However, the poor light conversion efficiency and severe stability problem hinder their widespread applications. In this work, a novel encapsulation strategy is developed through the in situ growth of CsPbX3 PQDs in presynthesized mesoporous cerium-based metal organic frameworks (Ce-MOFs) and further silane hydrolysis-encapsulation, generating stable CsPbX3@Ce-MOF@SiO2 composites with greatly enhanced light conversion efficiency. Moreover, the simulation results suggest that the pore boundary of Ce-MOFs has a strong waveguide effect on the incident PQD light, constraining PQD light inside the bodies of Ce-MOFs and suppressing reabsorption losses, thus increasing the overall light conversion efficiency of PQDs. Meanwhile, the Ce-MOF@SiO2 protective shell effectively improves the stability by blocking internally embedded PQDs from the harmful external environment. Further, the obtained white-light-emitting diode shows an ultrahigh luminous efficiency of 87.8 lm/W, which demonstrates their great potential in optoelectronic applications.

A Cerium-Based Metal-Organic Framework as Adsorbent for the 99mo/99mtc Generator

A Cerium-Based Metal-Organic Framework as Adsorbent for the 99mo/99mtc Generator

A Cerium-Based Metal-Organic Framework as Adsorbent for the 99mo/99mtc Generator

A Cerium-Based Metal-Organic Framework as Adsorbent for the 99mo/99mtc Generator

Rapid Synthesis of Mesoporous Cerium-Based Metal Organic Frameworks for Carbon Dioxide Adsorption and Selectivity

Rapid Synthesis of Mesoporous Cerium-Based Metal Organic Frameworks for Carbon Dioxide Adsorption and Selectivity

Highly stable and activated Cerium-based MOFs superstructures for ultrahigh selective uranium (VI) capture from simulated seawater

Metal-organic frameworks (MOFs) have attracted considerable attention owing to their tunable morphologies, open topological structures, large specific surface areas, and large number of active sites. These characteristics facilitate the potential application of MOFs to uranium extraction from seawater. Through calcination at low temperatures, activated MOFs with transition structures between MOFs and metal oxides can be prepared. Activated MOFs can not only maintain the structural advantages of the original material but can also expose many active metal sites. In this study, we rapidly synthesized Ce (1,3,5-Benzenetricarboxylic acid)3 (H2O)6 with a superstructure comprising one-dimensional nanorods at room temperature. Activated cerium-based metal-organic framework (CeMOF) with strong water stability was obtained via calcination in nitrogen at 150 °C. Furthermore, CeBTC-150 exhibited ultrahigh selectivity for uranium, and the distribution coefficient (Kd) reached approximately 3.5 × 105 mL/g. The proposed method yielded not only an efficient adsorbent for uranium extraction from simulated seawater but also an innovative concept for the extraction of uranium ions from seawater using activated MOFs.

Novel cerium-based MOFs photocatalyst for photocarrier collaborative performance under visible light

A novel cerium-based metal–organic framework crystal (Ce-TBAPy) was developed via a one-pot solvothermal method. Interestingly, the Ce-TBAPy photocatalyst material demonstrated an enhanced collaborative photoredox performance in terms of acetaldehyde degradation and water reduction, and the photoreaction rates of Ce-TBAPy shown about 5.06-times and 3.94-times higher, respectively, than those when untreated H4TBAPy was used. A significant finding is that the apparent quantum efficiency value of Ce-TBAPy for CO2 generation from CH3CHO decomposition performs 5.12% at 420 nm. The accumulation of abundant separated holes on the pyrene macrocycles could oxidize CH3CHO to CO2 easily. Meanwhile, cerium integration with TBAPy4− ligands to form a π-conjugated construction further resulted in sufficient photoinduced electrons and exhibited effective interfacial charge separation, which harvesting the reduction of H2O to H2 efficiently. The electronic localization influence arising from the formation of –COO-Ce functional groups in Ce-TBAPy and the direction of electron migration in the photocatalytic system were further confirmed by DFT calculation. This work provides an effective strategy to obtain rare earth-based MOF photocatalysts with dual redox functions and holds promise for advancing the prospect of using MOF materials to convert solar energy into chemical energy.

Proton-Conductive Cerium-Based Metal-Organic Frameworks.

In this study, proton-conducting behaviors of a cerium-based metal-organic framework (MOF), Ce-MOF-808, its zirconium-based isostructural MOF, and bimetallic MOFs with various Zr-to-Ce ratios are investigated. The significantly increased proton conductivity (σ) and decreased activation energy (Ea) are obtained by substituting Zr with Ce in the nodes of MOF-808. Ce-MOF-808 achieves a σ of 4.4 × 10-3 S/cm at 25 °C under 99% relative humidity and an Ea of 0.14 eV; this value is among the lowest-reported Ea of proton-conductive MOFs. Density functional theory calculations are utilized to probe the proton affinities of these MOFs. As the first study reporting the proton conduction in cerium-based MOFs, the finding here suggests that cerium-based MOFs should be a better platform for the design of proton conductors compared to the commonly reported zirconium-based MOFs in future studies on energy-related applications.

Ce-MOF nanorods/aluminum hydroxide (AlTH) synergism effect on the fire-retardancy/smoke-release and thermo-mechanical properties of a novel thermoplastic acrylic intumescent composite coating

The development of novel fire/smoke-retardant agents for the intumescent polymeric-based coatings has grown expeditiously in recent researches. The use of ammonium poly-phosphate, [NH4PO3]n(OH)2, (APP), pentaerythritol, C5H12O4, (PER), and Melamine, C3H6N6, (MEL) mixture has been acknowledged as the reliable intumescent system for the coatings. However, there are a number of auxiliary materials which have been introduced for these intumescent coatings with the aim of decreasing the heat transfer, smoke production, and radical release and also increase of char strength, corrosion protection, and mechanical properties of the coatings. In this work, we synthesized cerium-based Metal-organic framework (MOF) nanoparticles as an additive for the acrylic-based intumescent system. The synthesis of MOF was proved and characterized by FE-SEM, XRD, and BET analysis. The effect of incorporation of the obtained MOFs and Aluminum hydroxide (AlTH) and also the synergistic effect of simultaneous use of these additives in the intumescent formulation on the fire retardancy, morphological and mechanical properties of char layer, and also the mechanical properties of the coating were studied in detail. The results showed that the synergism behavior of MOF and AlTH increased the heat-insulating index of the system by about 17%, and decreased the heat release rate and smoke production rate to 24.78 KJ/m2 and 31.84 m2, respectively. The synergistic effect of the additives has also improved the char forming, char strength and also hindered the detrimental effect of the intumescence system on the mechanical properties of the coating. The intumescence mechanism of the proposed coatings was discussed in detail using the results of TGA and FTIR analysis and study of decomposition kinetic.

Cerium-Based Metal–Organic Framework Nanorods Nucleated on CeO2 Nanosheets for Photocatalytic N2 Fixation and Water Oxidation

Cerium-Based Metal–Organic Framework Nanorods Nucleated on CeO₂ Nanosheets for Photocatalytic N₂ Fixation and Water Oxidation

The structural design and valence state control of cerium-based metal-organic frameworks for their highly efficient phosphate removal

A series of cerium-based metal-organic frameworks (MOFs) with structural design and valence state modulation were fabricated for effective phosphate uptake, which were named as Ce-BDC-1, Ce-BDC-2 and Ce-BTC-1. The X-ray diffractometer (XRD) pattern revealed that Ce-BTC-1 was highly coordinatively unsaturated MOF. The Brunauer-Emmett-Teller analysis (BET) confirmed that Ce-BDC-1 possessed the largest specific surface area of 1285.57 m2/g, two-fold higher than the area of Ce-BTC-1 and thousand times larger than that of Ce-BDC-2. The result of X-ray photoelectron spectroscopy (XPS) demonstrated that the dominant valence state of cerium in Ce-BDC-2 was Ce (Ⅲ), while Ce-BDC-1 and Ce-BTC-1 were totally Ce (Ⅳ)-based materials. Impressively, although the physicochemical characteristics were quite divergent, Ce-BTC-1, Ce-BDC-1 and Ce-BDC-2 showed relatively close phosphate removal capacities (the maximum adsorption capacities of them were 242.0, 254.3 and 218.9 mg/g, respectively). Meanwhile, the variety of structure modification or valence state selection would in return affect their adsorption performances, leading to show their own advantage in different removal characteristics like fast adsorption speed, superb uptake capacity in solution with low or high concentration. This study provided three different strategies for preparing high-effective cerium-based adsorbents and revealed the relationship among physicochemical characteristics, adsorption mechanisms and adsorption performances, which might contribute to the design of new metal-based adsorbents.

Cerium based metal organic framework derived composite with reduced graphene oxide as efficient supercapacitor electrode

The excellent stability of CeO2 coupled with the high-level conductivity of CeS2 and enhanced electrochemical performance of rGO prove to be a workable nanocomposite electrode for supercapacitor applications. Here in this work, we synthesized mesoporous Ce-BTC metal-organic framework (MOF) derived CeO2/rGO composite, which was then subjected to sulfidation to prepare CeO2/rGO/CeS2 nanocomposite, which was characterized by XRD, SEM, EDS, and TGA to find out its crystalline nature, material composition, morphology, and thermal stability. The electrochemical behavior of the metal oxide/sulfide composite was studied by making use of the cyclic voltammetry analysis (CV), chronopotentiometry (CP), and electrochemical impedance spectroscopy (EIS). The as-produced porous CeO2/rGO/CeS2 composite demonstrated the highest specific capacitance of 720 Fg−1 in 3 M KOH electrolyte, with the specific energy and specific power of 23.5 Whkg−1, and 2917.2 Wkg−1 correspondingly, at a current density of 2.5 Ag−1. The electrode demonstrated exceptional cyclic stability over 3000 cycles at a 100mVs−1 scan rate. The brilliant electrochemical efficacy of the synthesized material was ascribed to its tiered structure. The obtained results show that the CeO2/rGO/CeS2 composite opens new possibilities of metal sulfide composites as efficient electrodes for supercapacitor applications.

Ce-TA MOF assembled GO nanosheets reinforced epoxy composite for superior thermo-mechanical properties

BackgroundRecently, graphene oxide has been used for different purposes i.e., for improving the thermo-mechanical properties of polymer coatings. In this research, for the first time, the eco-friendly cerium-based Metal-Organic Framework aligned Graphene Oxide (GO/Ce-TA MOF) was developed to enhance the tensile stress and fracture toughness of the epoxy matrix. Moreover, the mechanical and thermal stability of the Ce-TA MOF reinforced polymer coating was studied. MethodsThe morphological characterization, stability, functionality, and the individual structure of the prepared epoxy nanocomposites were surveyed by the FE-SEM (Field Emission Scanning Electron Microscopes), tensile test, and DMTA (Dynamic Mechanical Thermal Analysis). The GO, Ce-TA MOF, and GO/Ce-TA MOF chemical composition and structure were studied by Raman, XRD (X-ray Powder Diffraction), FT-IR (Fourier Transform Infrared Spectroscopy), Pull-off adhesion test, Impact test, and FE-SEM approaches. Significant findingsAt first, the epoxy composites' cross-sectional profiles, illustrating the fracture morphology, were strong evidence for proving the high toughening properties and the uniform dispersion degree of the Ce-based MOFs particles in the epoxy matrix. The thermal resistance of the Ce-TA MOF and GO/Ce-TA MOF reinforced coatings was increased about 20% and 30%, respectively, compared with the neat epoxy matrix. The Pull-off adhesion test results revealed no coating detachment after the introduction of the Ce-TA MOF and GO/Ce-TA MOF into the epoxy coating. Besides, the results of the impact test displayed that the addition of the additives to the epoxy matrix met the resistance of the coating to the mechanical damage. The outcomes of the tensile test have demonstrated about 275% and 195% improvement in the breakpoint energy, and 90% and 60% breakthrough in the tensile strength of the Ce-TA MOF and GO/Ce-TA MOF nanocomposites, respectively. The ultimate results asserted that the mechanical performance of the Ce-TA MOF could be considered more noticeable than the GO/Ce-TA MOF particles.

Visible Light‐Driven BiOBr/Bi2S3@CeMOF Heterostructured Hybrid with Extremely Efficient Photocatalytic Reduction Performance of Nitrophenols: Modeling and Optimization

AbstractThe one‐pot facile solvothermal process was applied to designed BiOBr/Bi2S3 heterostructured microspheres. The hierarchical BiOBr/Bi2S3 photocatalyst is integrating by solid‐state adding of cerium based metal‐organic frameworks (CeMOF) using ball mill to fabricate a novel BiOBr/Bi2S3@CeMOF. The synthesized photocatalysts were examined by XRD (X‐Ray diffraction), Raman, FTIR (Fourier transform infrared spectroscopy), XPS (X‐Ray photoelectron spectroscopy), FESEM (field emission transmission electron microscopy), FETEM (field emission scanning electron microscopy), UV‐Vis DRS (ultraviolet‐visible diffuse reflectance), PL (Photoluminescence), and transient photocurrent analysis. The as‐prepared BiOBr/Bi2S3@CeMOF photomaterial displays considerably enhanced photocatalytic activity for reduction of 4‐nitrophenol (4NP) to 4‐aminophenol (4AP) compared with the pristine BiOBr and BiOBr/Bi2S3 composite under the irradiation of visible light. The promising BiOBr/Bi2S3@CeMOF photocatalyst exhibit the highest photoreduction efficiency of 4NP along with the highest reaction rate (K) (R: 98 %; K: 3.91 min−1 ) compared with the other as‐prepared materials such as CeMOF (R:38 %; 0.23 min−1), BiOBr (R: 48 %; K: 0.65 min−1), Bi2S3 (R:68 %;0.92 min−1), and BiOBr/Bi2S3 (R: 75 %; K: 1.38 min−1) photocatalysts after 30 min of visible light irradiation. The boosted photocatalytic efficiency is attributed to creating the heterojunction at the interface of BiOBr/Bi2S3@CeMOF, which can powerfully facilitate the separation of the photogenerated carriers. After that, the Box‐Behnken design was applied to indicate the optimum condition for the reduction of 4NP under the effect of different variables (e. g., the concentration of NP (A:), pH (B), and concentration of NaBH4 (C). At the optimum condition (A: 14.5μmol L−1, B: 5, and C: 0.88 mol L−1), the photoreduction efficiency (%) of the 4NP is 99.7 %. BiOBr/Bi2S3@CeMOF catalyst exhibits excellent photoreduction stability over five successive reaction runs.

From Trash to Treasure: Probing Cycloaddition and Photocatalytic Reduction of CO2 over Cerium-Based Metal–Organic Frameworks

Fixing the greenhouse gas CO2 via cycloaddition reactions to value-added cyclic carbonates or photocatalytic reduction of CO2 to produce desirable fuels is the most coveted, although challenging, e...

Cerium-Based Metal-Organic Framework Nanocrystals Interconnected by Carbon Nanotubes for Boosting Electrochemical Capacitor Performance.

In this study, nanocrystals of a cerium-based metal-organic framework (Ce-MOF), Ce-MOF-808, are directly grown on the surface of carboxylic acid-functionalized carbon nanotubes (CNTs) by a facile one-step solvothermal synthesis method. Ce-MOF-CNT nanocomposites with various Ce-MOF-to-CNT ratios are synthesized, and their crystallinity, morphology, porosity, and electrical conductivity are examined. The redox-hopping and electrochemical behaviors of the pristine Ce-MOF in aqueous electrolytes are investigated, suggesting that the pristine Ce-MOF is electrochemically active but possesses a limited charge-transport behavior. As a demonstration, all the Ce-MOF, CNT, and nanocomposites are used as active materials for application in aqueous-based supercapacitors. The capacitive performance of the CNT can be significantly boosted with the help of redox-active Ce-MOF-808 nanocrystals.