Ni nanocatalysts supported on MIL-53(Al) for DCPD hydrogenation

Metal organic frameworks (MOFs) with many unique advantages have drawn wide attention in the field of catalysis. However, the poor structural stability of MOFs limits its application. Heat treatment for MOFs can enhance its electrical conductivity and structural stability, which helps to improve the catalytic performance. Ni nanoparticles supported on MIL-53(Al) were synthesized through different heat treatment temperature. Catalysts with uniform distribution of active nickel and rich mesoporous structure were obtained by adjusting the heat treatment temperature to 500 °C. The results show this catalyst has the best hydrogenation activity and stability. Under the reaction conditions of 60 °C and 2 h, the conversion rate of DCPD is 100%, and the selectivity of endo-THDCPD is higher than 95%. After five cycles, the catalyst also show excellent stability and high activity, the conversion rate of DCPD is still 100%.

Supported Ni catalyst with rich mesoporous structure and uniform distribution of Ni shows high catalytic activity performance toward the hydrogenation of DCPD.     

Fluorinated MIL-101 for carbon capture utilisation and storage: uptake and diffusion studies under relevant industrial conditions

Carbon capture utilisation and storage (CCUS) using solid sorbents such as zeolites, activated carbon and Metal–Organic Frameworks (MOFs) could facilitate the reduction of anthropogenic CO₂ concentration. Developing efficient and stable adsorbents for CO₂ capture as well as understanding their transport diffusion limitations for CO₂ utilisation plays a crucial role in CCUS technology development. However, experimental data available on CO₂ capture and diffusion under relevant industrial conditions is very limited, particularly for MOFs. In this study we explore the use of a gravimetric Dynamic Vapour Sorption (DVS) instrument to measure low concentration CO₂ uptake and adsorption kinetics on a novel partially fluorinated MIL-101(Cr) saturated with different water vapour concentrations, at ambient pressure and temperature. Results show that up to water P/P₀ = 0.15 the total CO₂ uptake of the modified material improves and that the introduction of small amounts of water enhances the diffusion of CO₂. MIL-101(Cr)-4F(1%) proved to be a stable material under moist conditions compared to other industrial MOFs, allowing facile regeneration under relevant industrial conditions.

MIL-101(Cr)-4F(1%) proved to be a stable material under moist conditions compared to other industrial MOFs, with facile regeneration under relevant industrial conditions; plus the introduction of small amounts of water enhances the diffusion of CO₂.     

In situ Raman and FTIR spectroscopic study on the formation of the isomers MIL-68(Al) and MIL-53(Al)

The topological metal–organic framework isomers MIL-53 and MIL-68 form from similar educts but differ in their pore geometries. They have been known for several years, but their synthesis is always reported separately. In consequence, the underlying mechanism and decisive synthesis parameters leading to the formation of either MIL-53 or MIL-68 are not understood. The present study shows how to induce the formation of MIL-68(Al) rather than MIL-53(Al) at low synthesis temperatures in N,N-dimethylformamide (DMF) using a modulated synthesis approach. MIL-68(Al) is identified as the intermediate product of formic acid modulated synthesis, which converts into the thermodynamically stable MIL-53(Al) product at longer synthesis times. The interactions of formic acid with the synthesis precursors responsible for inducing MIL-68(Al) formation are investigated with in situ Raman and FTIR spectroscopy. In contrast to the commonly assumed modulation mechanism of competitive coordination of linker and modulator with the metal node, formic acid is shown to form hydrogen bonds via the carboxylic group of the terephthalic acid (H₂BDC) linker, slowing prenucleation building unit and subsequent crystal growth. MIL-68(Al) formation is favored by the combination of a deficiency of terephthalic acid in solution and a slow MOF growth rate. Dissolved H₂BDC in solution is proposed to hinder MIL-68(Al) formation by serving as a molecular template for the rhombic MIL-53(Al) pore channels.

The paper describes a method to induce the formation of MIL-68(Al) rather than MIL-53(Al) using a formic acid modulated synthesis approach.     

Sulfadiazine hosted in MIL-53(Al) as a biocide topical delivery system

Sulfadiazine (SDZ), a bacteriostatic agent, was hosted in a metal–organic framework, specifically in MIL-53(Al) and modified-zinc MIL-53(Al,Zn). Materials were characterized structural, and texturally. Both hosts loaded sulfadiazine but they were differenced regarding the release of sulfadiazine. The presence of zinc plays a significant role to the modulation of sulfadiazine–MOF interactions. Release of sulfadiazine from sulfadiazine@MOFs was monitored in vitro and ex vivo conditions. A kinetic release model is proposed for in vitro sulfadiazine release. Remarkably, the materials did not show cytotoxicity against eukaryote cells.

Sulfadiazine (SDZ), a bacteriostatic agent, was hosted in MIL-53(Al) and modified-zinc MIL-53(Al,Zn).     

High removal of thiophene from model gasoline by porous MIL-101(Cr)/SA hybrid membrane

Membrane separation technologies have great promising potential for applications in several industries. Metal–organic frameworks (MOFs), for their large surface areas, low framework densities, transition-metal ions in the skeleton and high pore volumes relative to other porous matrices, have great potential for the removal of sulfur from gasoline with high efficiency. In the present study, a novel porous membrane adsorbent MIL-101(Cr)/SA was prepared by immobilizing MIL-101(Cr) onto sodium alginate (SA) matrix, which can combine the size/shape selectivity of MIL-101(Cr) with the processability and mechanical stability of SA polymer. The physico-chemical properties of MIL-101(Cr)/SA were investigated by FT-IR, SEM, BET, XRD and EDX methods. To investigate the effects of some important factors on the adsorption behavior for thiophene, a batch of experiments were performed by changing the concentration of porogen polyethylene glycol in the MIL-101(Cr)/SA, solution temperature, initial thiophene concentration and contact time. Meanwhile, benzothiophene, thiophene and 3-methyl thiophene were used to test the selectivity of MIL-101(Cr)/SA. The MIL-101(Cr)/SA showed an excellent uptake capacity of 671 mg g⁻¹ under the optimal adsorption conditions. Selectivity testing indicated that the uptake capacity of MIL-101(Cr)/SA follows the order of benzothiophene > thiophene > 3-methyl thiophene. Kinetics experiments indicated the pseudo-second-order model displayed good correlation with adsorption kinetics data. The Crank model showed that the intraparticle solute diffusion is the rate-controlling adsorption step. Regeneration experiment result shows that the prepared MIL-101(Cr)/SA has excellent adsorption and desorption efficiencies.

Membrane separation technologies have great promising potential for applications in several industries.     

Li-doped beryllonitrene for enhanced carbon dioxide capture

In recent years, the scientific community has given more and more attention to the issue of climate change and global warming, which is largely attributed to the massive quantity of carbon dioxide emissions. Thus, the demand for a carbon dioxide capture material is massive and continuously increasing. In this study, we perform first-principle calculations based on density functional theory to investigate the carbon dioxide capture ability of pristine and doped beryllonitrene. Our results show that carbon dioxide had an adsorption energy of −0.046 eV on pristine beryllonitrene, so it appears that beryllonitrene has extremely weak carbon dioxide adsorption ability. Pristine beryllonitrene could be effectively doped with lithium atoms, and the resulting Li-doped beryllonitrene had much stronger interactions with carbon dioxide than pristine beryllonitrene. The adsorption energy for carbon dioxide on Li-doped beryllonitrene was −0.408 eV. The adsorption of carbon dioxide on Li-doped beryllonitrene greatly changed the charge density, projected density of states, and band structure of the material, demonstrating that it was strongly adsorbed. This suggests that Li-doping is a viable way to enhance the carbon dioxide capture ability of beryllonitrene and makes it a possible candidate for an effective CO₂ capture material.

Lithium-doped beryllonitrene monolayer can effectively chemisorb carbon dioxide molecules.     

Comparative research on three types of MIL-101(Cr)-SO3H for esterification of cyclohexene with formic acid

MIL-101(Cr)-SO₃H was prepared by a one-pot synthesis method using CrO₃ or Cr(NO₃)₃^·9H₂O as a Cr source and 2-sulfoterephthalic acid monosodium salt as a ligand with three different mineralizers, HCl, HF and NaAC, respectively. Among the prepared catalysts, MIL-101(Cr)-SO₃H, which uses HCl as a mineralizer, has a high specific surface area and the strongest acidity compared with the other two mineralizers. When these catalysts were used to catalyze the esterification of cyclohexene with formic acid, MIL-101(Cr)-SO₃H prepared using HCl as a mineralizer possessed the highest catalytic activity in the esterification, because the conversion rate of cyclohexene is 63.97%, whereas MIL-101(Cr)-SO₃H prepared using NaAC and HF as a mineralizer shows cyclohexene conversion rates of 38.40% and 32.46%, while their selectivity to cyclohexyl formate is about 97.50%. MIL-101(Cr)-SO₃H with HCl as a mineralizer can be reused three times in succession without any loss of catalytic activity.

MIL-101(Cr)-SO₃H was prepared with three different mineralizers, namely HCl, HF and NaAC, respectively. And catalytic performance and stability of three samples catalyzing the esterification of cyclohexene with formic acid were compared.     

Adsorption characteristics of metal–organic framework MIL-101(Cr) towards sulfamethoxazole and its persulfate oxidation regeneration

A metal–organic framework, MIL-101(Cr), was used to adsorb sulfamethoxazole (SMZ) in water and activated persulfate (PS) oxidation was investigated to regenerate SMZ-saturated MIL-101(Cr). Adsorption and oxidation were combined in this study. MIL-101(Cr) was characterized by SEM, BET, XPS and FT-IR analyses. Effects of various operating parameters on adsorption efficiency were studied. The dosages of persulfate for SMZ desorption and oxidation were investigated. The results showed that the recommended pH was 6–8 for SMZ adsorption and optimum MIL-101(Cr) dosage was 0.1 g L⁻¹. SMZ adsorption by MIL-101(Cr) was a spontaneous process and nearly exothermic. Saturation adsorption capacity was achieved in 180 s and the adsorption followed the pseudo-second-order model. The maximum adsorption amount of MIL-101(Cr) to SMZ was 181.82 mg g⁻¹ (Langmuir). MIL-101(Cr) also showed good adsorption capacities for sulfachloropyridazine (SCP), sulfamonomethoxine (SMM), and sulfadimethoxine (SDM). Persulfate was helpful for SMZ desorption from the surface of saturated MIL-101(Cr) and sufficient persulfate could simultaneously oxidize the SMZ. XPS analysis showed that the structure of MIL-101(Cr) was stable after the persulfate oxidation process. Regenerated MIL-101(Cr) had the same level of adsorption capacity as fresh MIL-101(Cr). An adsorption–oxidation combined process may be set up based on the results. This study provides basic data for the deep treatment of organic micropollutants in urban water bodies.

A metal–organic framework, MIL-101(Cr), was used to adsorb sulfamethoxazole (SMZ) in water and activated persulfate (PS) oxidation was investigated to regenerate SMZ-saturated MIL-101(Cr).     

Fabrication of UiO-66/MIL-101(Fe) binary MOF/carboxylated-GO composite for adsorptive removal of methylene blue dye from aqueous solutions

This study provides a novel composite as an efficient adsorbent of cationic methylene blue dye. UiO-66/MIL-101(Fe) binary metal organic framework (MOF) was fabricated using a solvothermal technique. Additionally, the developed binary MOF was modified with carboxylated graphene oxide (GOCOOH) using a post-synthetic technique. The as-fabricated UiO-66/MIL-101(Fe)-GOCOOH composite was analyzed by FTIR, XRD, SEM, BET, TGA, XPS and zeta potential analysis. The adsorption performance of UiO-66/MIL-101(Fe)-GOCOOH composite was examined for its aptitude to adsorb cationic MB dye using a batch technique. The obtained data revealed that, the developed UiO-66/MIL-101(Fe)-GOCOOH composite exhibited higher adsorption capacity compared to UiO-66/MIL-101(Fe) binary MOF. Adsorption isotherms and kinetic studies revealed that MB dye adsorption onto UiO-66/MIL-101(Fe)-GOCOOH composite fitted a Langmuir isotherm model (q_m = 448.71 mg g⁻¹) and both pseudo 1^st order and pseudo 2^nd order kinetic models. An intra-particle diffusion model showed that the adsorption process occurs through three steps. Besides, thermodynamic data reflected that the adsorption of MB onto UiO-66/MIL-101(Fe)-GOCOOH composite is an endothermic and spontaneous process and the adsorption involves both physisorption and chemisorption interactions. The as-fabricated UiO-66/MIL-101(Fe)-GOCOOH composite exhibited good reusability and can be considered as a promising reusable adsorbent for the treatment of dye-containing industrial effluents with high efficiency.

This study provides a novel composite as an efficient adsorbent of cationic methylene blue dye.     

Bimetallic Au–Pd alloy nanoparticles supported on MIL-101(Cr) as highly efficient catalysts for selective hydrogenation of 1,3-butadiene

Gold–palladium (Au–Pd) bimetallic nanoparticle (NP) catalysts supported on MIL-101(Cr) with Au : Pd mole ratios ranging from 1 : 3 to 3 : 1 were prepared through coimpregnation and H₂ reduction. Au–Pd NPs were homogeneously distributed on the MIL-101(Cr) with mean particle sizes of 5.6 nm. EDS and XPS analyses showed that bimetallic Au–Pd alloys were formed in the Au(2)Pd(1)/MIL-101(Cr). The catalytic performance of the catalysts was explored in the selective 1,3-butadiene hydrogenation at 30–80 °C on a continuous fixed bed flow quartz reactor. The bimetallic Au–Pd alloy particles stabilized by MIL-101(Cr) presented improved catalytic performance. The as-synthesized bimetallic Au(2)Pd(1)/MIL-101(Cr) with 2 : 1 Au : Pd mole ratio showed the best balance between the activity and butene selectivity in the selective 1,3-butadiene hydrogenation. The Au–Pd bimetallic-supported catalysts can be reused in at least three runs. The work affords a reference on the utilization of a MOF and alloy nanoparticles to develop high-efficiency catalysts.

Bimetallic Au–Pd alloy particles stabilized by MIL-101(Cr) showed high activity and butene selectivity for 1,3-butadiene hydrogenation reaction.     

Nanoporous MIL-101(Cr) as a sensing layer coated on a quartz crystal microbalance (QCM) nanosensor to detect volatile organic compounds (VOCs)

The application of metal–organic frameworks (MOFs) as a sensing layer has been attracting great interest over the last decade, due to their high porosity and tunability, which provides a large surface area and active sites for trapping or binding target molecules. MIL-101(Cr) is selected as a good candidate from the MOFs family to fabricate a quartz crystal microbalance (QCM) nanosensor for the detection of volatile organic compound (VOC) vapors. The structural and chemical properties of synthesized MIL-101(Cr) are investigated by X-ray diffraction (XRD), Fourier-transfer infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) and so on. A stable and uniform layer of MOF is coated onto the surface of a QCM sensor by the drop casting method. The frequency of the QCM crystal is changed during exposure to different concentrations of target gas molecules. Here, the sensor response to some VOCs with different functional groups and polarities, such as methanol, ethanol, isopropanol, n-hexane, acetone, dichloromethane, chloroform, tetrahydrofuran (THF), and pyridine under N₂ atmosphere at ambient conditions is studied. Sensing properties such as sensitivity, reversibility, stability, response time, recovery time, and limit of detection (LOD) of the sensor are investigated. The best sensor response is observed for pyridine detection with sensitivity of 2.793 Hz ppm⁻¹. The sensor shows short response/recovery time (less than two minutes), complete reversibility and repeatability which are attributed to the physisorption of the gases into the MOF pores and high stability of the device.

Metal–organic frameworks can be used as sensing layer in QCM fabrication because of their huge surface area.     

Amine-functionalized MIL-53(Al) with embedded ruthenium nanoparticles as a highly efficient catalyst for the hydrolytic dehydrogenation of ammonia borane

Well-dispersed ruthenium nanoparticles (Ru NPs) are immobilized within the pores of amine-functionalized MIL-53 via an in situ impregnation-reduction method. The resulting Ru/MIL-53(Al)-NH₂ catalyst exhibits superior catalytic performance for the dehydrogenation of ammonia borane (AB) at ambient temperature relative to the Ru/MIL-53(Al) catalyst; it has a turnover frequency (TOF) of 287 mol H₂ min⁻¹ (mol Ru)⁻¹ and an activation energy (E_a) of 30.5 kJ mol⁻¹. The amine groups present in the MIL-53(Al)-NH₂ framework facilitate the formation and stabilization of ultra-small Ru NPs by preventing their aggregation. Additionally, the Ru/MIL-53(Al)-NH₂ catalyst exhibits satisfactory durability and reusability: 72.4% and 86.3% of the initial catalytic activity was maintained after the fifth successive cycle of the hydrolytic dehydrogenation of AB in the two respective tests.

The performance of Ru-based catalyst for hydrolysis of AB can be significantly enhanced through amine-functionalization of the MOF material.     

A mild and efficient method for the synthesis of pyrroles using MIL-53(Al) as a catalyst under solvent-free sonication

A highly efficient method for the synthesis of pyrroles using MIL-53(Al) as a catalyst has been developed under solvent-free sonication. This reaction has a broad substrate scope and high yields were obtained within a short reaction time. Remarkably, no additional additives and volatile organic solvent are required for this method and the MIL-53(Al) could be recovered and reused several times without significant drop-off in catalytic activity.

Catalytic activity of MIL-53(Al) in the synthesis of pyrroles under solvent-free sonication.     

MIL-101(Cr)–cobalt ferrite magnetic nanocomposite: synthesis,characterization and applications for the sonocatalytic degradation of organic dye pollutants

In this study, for the first time, a novel magnetically recyclable MIL-101(Cr)/CoFe₂O₄ nanocomposite was prepared via a facile solvothermal method. The morphology, structural, magnetic and optical properties of the nanocomposite were characterized via field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), UV-visible spectroscopy (UV-visible) and BET surface area analysis. Furthermore, the sonocatalytic activity of the MIL-101(Cr)-based magnetic nanocomposite was explored for the degradation of organic dye pollutants such as Rhodamine B (RhB) and methyl orange (MO) under ultrasound irradiation in the presence of H₂O₂. Under optimized conditions, the degradation efficiency reached 96% for RhB and 88% for MO. The sonocatalytic activity of MIL-101(Cr)/CoFe₂O₄ was almost 12 and 4 times higher than that of the raw MIL-101(Cr) and pure CoFe₂O₄, respectively. The improved sonocatalytic performance of the as-prepared binary nanocomposite can be attributed to the relatively high specific surface area of MIL-101(Cr) and magnetic property of CoFe₂O₄, as well as the fast generation and separation of charge carriers (electrons and holes) in MIL-101(Cr) and CoFe₂O₄. In addition, the trapping tests demonstrated that ·OH radicals are the main active species in the dye degradation process. Moreover, the most influencing factors on the sonocatalytic activity such as the H₂O₂ amount, initial dye concentration and catalyst dosage were investigated. Finally, the nanocomposite was magnetically separated and reused without any observable change in its structure and performance even after four consecutive runs.

A magnetically separable MIL-101(Cr)/CoFe₂O₄ binary nanocomposite was prepared via a hydrothermal route and applied as a sonocatalyst for the efficient degradation of organic dyes.     

Conducting polymer-coated MIL-101/S composite with scale-like shell structure for improving Li–S batteries

Lithium–sulfur batteries are regarded as a promising energy storage system. However, they are plagued by rapid capacity decay, low coulombic efficiency, a severe shuttle effect and low sulfur loading in cathodes. To address these problems, effective carriers are highly demanded to encapsulate sulfur in order to extend the cycle life. Herein, we introduced a doped-PEDOT:PSS-coated MIL-101/S multi-core–shell structured composite. The unique structure of MIL-101, large specific area and conductive shell ensure high dispersion of sulfur in the composite and minimize the loss of polysulfides to the electrolyte. The doped-PEDOT:PSS-coated sulfur electrodes exhibited an increase in initial capacity and an improvement in rate characteristics. After 192 cycles at the current density of 0.1C, a doped-PEDOT:PSS-coated MIL-101/S electrode maintained a capacity of 606.62 mA h g⁻¹, while the MIL-101/S@PEDOT:PSS electrode delivered a capacity of 456.69 mA h g⁻¹. The EIS measurement revealed that the surface modification with the conducting polymer provided a lower resistance to the sulfur electrode, which resulted in better electrochemical behaviors in Li–S battery applications. Test results indicate that the MIL-101/S@doped-PEDOT:PSS is a promising host material for the sulfur cathode in the lithium–sulfur battery applications.

Lithium–sulfur batteries are regarded as a promising energy storage system.     

MIL-53 and its OH-bonded variants for bio-polyol adsorption from aqueous solution

The adsorption of bio-polyols from dilute aqueous solution is important but faces challenges in the sustainable bio-refinery process. One solution to increase adsorption efficiency is to leverage host–guest interactions between the polyols and materials to grant a preference for polyols. In this study, we synthesized MIL-53 and diverse OH-bonded variants, and studied their adsorption properties towards ethanediol, 1,3-propanediol and glycerol in water. Among the four materials, OH–MIL-53 exhibited fast adsorption kinetics and high capacity, and could be completely regenerated through ethanol elution. Hydrophobic interactions between the alkyl chains of the polyols and the organic linkers of OH–MIL-53 and hydrogen bonding interactions between their OH groups were identified. The synergistic effect of the host–guest interactions is responsible for the unique adsorption performances of OH–MIL-53 towards polyols, and particularly for 1,3-propanediol.

Delicate host–guest interaction drives OH-bonded MOF to capture bio-polyols from diluted aqueous solution, with high capacity, fast kinetics and recyclability.     

Hexamethylenetetramine-based ionic liquid/MIL-101(Cr) metal–organic framework composite: a novel and versatile tool for the preparation of pyrido[2,3-d:5,6-d′]dipyrimidines

In the current paper, a hexamethylenetetramine-based ionic liquid immobilized on the MIL-101(Cr) metal–organic framework was successfully synthesized as a novel, efficient, and recoverable catalyst for the synthesis of pyrido[2,3-d:5,6-d′]dipyrimidine derivatives via the reaction of barbituric acid derivatives, 6-aminouracil/6-amino-1,3-dimethyl uracil, and aromatic aldehydes under solvent-free conditions. Characterization of the catalyst was carried out using various methods such as field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectrophotometry (FT-IR), and Brunauer–Emmett–Teller (BET). Efficient transformation, short reaction times, excellent yields, easy product isolation, mild conditions, and the potential high recyclability of the organocatalyst are the main features of this protocol.

In this study, HMTA-BAIL@MIL-101(Cr) was prepared as a novel catalyst for the synthesis of dipyrimidine derivtives by the reaction of barbituric acids, 6-aminouracil/6-amino-1,3-dimethyl uracil, and arylaldehydes under solvent-free conditions.     

Controlling the nucleophilic properties of cobalt salen complexes for carbon dioxide capture

The nucleophilic properties of cobalt salen complexes are examined using density functional theory to investigate its carbon fixing capacity. In particular, carbon dioxide attack on neutral and anionic cobalt salen molecules is considered. Carbon fixation occurs for the anionic cobalt salen complex and is due to the nucleophilic interaction between the cobalt center and carbon dioxide molecule in a Co d_z²–CO₂ π* interaction. A minimum energy path search by a nudged elastic band calculation reveals a lower forward activation energy for the anionic complex than the neutral complex, indicating that the formation of the anionic complex is thermodynamically and kinetically favored. In this case, the CO₂ molecule is chemisorbed as partial charge transfer from the cobalt center to carbon dioxide is observed. Proposed reaction mechanisms explain how the Co–C bond energy of the CO₂–cobalt salen complex can be tuned by appropriate substitutions of electron donating or withdrawing groups on the phenyl ring.

The nucleophilic properties of cobalt salen complexes are examined using density functional theory to investigate its carbon fixing capacity.     

Activation of persulfates by ferrocene–MIL-101(Fe) heterogeneous catalyst for degradation of bisphenol A

In this study, a novel and high-performance catalyst was prepared and used as the heterogeneous catalyst to activate persulfate for bisphenol A (BPA) degradation. Ferrocene was anchored to NH₂-MIL-101(Fe) post-synthetically by the condensation of amine group from NH₂-MIL-101(Fe) with the carbonyl group of ferrocenecarboxaldehyde. The synthesized ferrocene tethered MIL-101(Fe)–ferrocene was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photo-electron spectra, cyclic voltammetry and electrochemical impedance spectroscopy. The ferrocene acts as a redox mediator, which makes the ferrocene functionalized NH₂-MIL-101(Fe) highly active in the degradation of BPA by accelerating the rate of the charge-transfer processes in aqueous solution. MIL-101(Fe)–Fc was proved to be the most effective catalyst, removing more than 99.9% of BPA. In addition, the catalyst can be reused without significant loss in activity.

In this study, a novel and high-performance catalyst ferrocene-MIL-101(Fe) was prepared and used as the heterogeneous catalyst to activate persulfate for bisphenol A degradation.     

Synthesis of some new distyrylbenzene derivatives using immobilized Pd on an NHC-functionalized MIL-101(Cr) catalyst: photophysical property evaluation,DFT and TD-DFT calculations

In this study the catalytic application of a heterogeneous Pd-catalyst system based on metal organic framework [Pd–NHC–MIL-101(Cr)] was investigated in the synthesis of distyrylbenzene derivatives using the Heck reaction. The Pd–NHC–MIL-101(Cr) catalyst showed high efficiency in the synthesis of these π-conjugated materials and products were obtained in high yields with low Pd-contamination based on ICP analysis. The photophysical behaviors for some of the synthesized distyrylbenzene derivatives were evaluated. The DFT and TD-DFT methods were employed to determine the optimized molecular geometry, band gap energy, and the electronic absorption and emission wavelengths of the new synthesized donor–π–acceptor (D–π–A) molecules in the gas phase and in various solvents using the chemical model B3LYP/6-31+G(d,p) level of theory.

The Pd–NHC–MIL-101(Cr) catalyst was found to be an efficient heterogeneous catalyst in the synthesis of DSB and stilbene π-conjugated materials using Heck chemistry.