Academic literature on the topic 'MOF UiO(Zr)'

Tujuan dari penelitian ini adalah untuk mengetahui nilai loading ibuprofen pada material UiO-66 (Zr-Metal Organic Framework). Pada penelitian ini, dilakukan variasi lama perendaman 12, 24, 36, 48, 60 dan 72 jam, sehingga didapatkan nilai drug loading yang optimal. Nilai drug loading ibuprofen diukur menggunakan spektrofotometer UV-VIS. Adapun penyimpanan ibuprofen dalam UiO-66 dikonfirmasi dengan XRD, FTIR, dan SEM-EDX. Hasil analisa gugus fungsi sampel dengan Fourier-Transform Infra Red (FTIR) dari Zr-MOF menunjukkan bahwa puncak khas dari UiO-66 juga muncul pada 663, 748 dan 547 cm-1 yang menunjukkan adanya interaksi Zirkonium (Zr) dengan ligan H2BDC, setelah UiO-66 digunakan untuk loading Ibuprofen tidak mengubah posisi dari puncak-puncak UiO-66. Namun, terjadi penurunan intensitas dan hilangnya puncak disekitar 1300 cm-1 yang dikarenakan interaksi antara UiO-66 dengan ibuprofen. Pola difraktogram UiO-66 sebelum dan sesudah loading ibuprofen yang menunjukkan bahwa UiO-66 yang terbentuk memiliki puncak karakteristik UiO-66 pada 7,3o. Mikrograf UiO-66 sebelum dan setelah loading ibuprofen memiliki morfologi kubus. Namun, setelah loading ibuprofen terdapat bagian seperti karang putih, ukuran yang terlihat lebih besar, serta pengurangan ruang kosong permukaan material. Uji Drug Loading Ibuprofen pada UiO-66 menunjukkan loading optimum ibuprofen dalam Zr-MOF mencapai 82,79% pada waktu pengadukan 72 jam.

There is an increasing interest in developing cost-effective technologies to produce hydrogen from sustainable resources. Herein we show a comprehensive study on the use of metal–organic frameworks (MOFs) as heterogeneous photocatalysts for H2 generation from photoreforming of glycerol aqueous solutions under simulated sunlight irradiation. The list of materials employed in this study include some of the benchmark Zr-MOFs such as UiO-66(Zr)-X (X: H, NO2, NH2) as well as MIL-125(Ti)-NH2 as the reference Ti-MOF. Among these solids, UiO-66(Zr)-NH2 exhibits the highest photocatalytic H2 production, and this observation is attributed to its adequate energy level. The photocatalytic activity of UiO-66(Zr)-NH2 can be increased by deposition of small Pt NPs as the reference noble metal co-catalyst within the MOF network. This photocatalyst is effectively used for H2 generation at least for 70 h without loss of activity. The crystallinity of MOF and Pt particle size were maintained as revealed by powder X-ray diffraction and transmission electron microscopy measurements, respectively. Evidence in support of the occurrence of photoinduced charge separation with Pt@UiO-66(Zr)-NH2 is provided from transient absorption and photoluminescence spectroscopies together with photocurrent measurements. This study exemplifies the possibility of using MOFs as photocatalysts for the solar-driven H2 generation using sustainable feedstocks.

Lead detection for biological environments, aqueous resources, and medicinal compounds, rely mainly on either utilizing bulky lab equipment such as ICP-OES or ready-made sensors, which are based on colorimetry with some limitations including selectivity and low interference. Remote, rapid and efficient detection of heavy metals in aqueous solutions at ppm and sub-ppm levels have faced significant challenges that requires novel compounds with such ability. Here, a UiO-66(Zr) metal-organic framework (MOF) functionalized with SO3H group (SO3H-UiO-66(Zr)) is deposited on the end-face of an optical fiber to detect lead cations (Pb2+) in water at 25.2, 43.5 and 64.0 ppm levels. The SO3H-UiO-66(Zr) system provides a Fabry–Perot sensor by which the lead ions are detected rapidly (milliseconds) at 25.2 ppm aqueous solution reflecting in the wavelength shifts in interference spectrum. The proposed removal mechanism is based on the adsorption of [Pb(OH2)6]2+ in water on SO3H-UiO-66(Zr) due to a strong affinity between functionalized MOF and lead. This is the first work that advances a multi-purpose optical fiber-coated functional MOF as an on-site remote chemical sensor for rapid detection of lead cations at extremely low concentrations in an aqueous system.

Abstract In the present study, a facile solvothermal method was used for the synthesis of silicotungstic acid (HSiW) immobilized on Ce-based metal organic framework (Ce-BDC) and embedded in Zr-based metal-organic framework (UiO-66(Zr)) composite catalyst, namely, Ce-BDC@HSiW@UiO-66 for the production of biodiesel through green fatty acid esterification. The obtained hybrids were characterized by various characterization technologies, including Fourier transform infrared, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 physisorption, X-ray photoelectron spectroscopy, and temperature-programmed desorption of NH3 (NH3-TPD) analysis. The characterization analyses showed that the hybrids have been successfully synthesized. Also, the volume and pore size of UiO-66(Zr) were changed by introducing HSiW@Ce-BDC, and the resulting Ce-BDC@HSiW@UiO-66 possessed the mesoporous structure and relatively high surface area. Simultaneously, the NH3-TPD analysis of Ce-BDC@HSiW@UiO-66 reveals that the acid strength was increased in comparison with HSiW@Ce-BDC. In addition, the composite Ce-BDC@HSiW@UiO-66 demonstrated high catalytic activity, and the oleic acid esterification gave 81.5% conversion at optimum conditions of 0.2 g catalysts, 1:30 oleic acid to methanol molar ratio at 130°C for 4 h. More interestingly, after six recycling cycles, the reduction in the conversion rate was only 4.6%, indicating that Ce-BDC@HSiW@UiO-66 has excellent reusability. Our study provides an effective approach to synthesize multifunctional hybrids for green biofuel production.

Colloidal dye-sensitized photocatalysis is a promising route toward efficient solar fuel production by merging properties of catalysis, support, light absorption, and electron mediation in one. Metal-organic frameworks (MOFs) are host materials with modular building principles allowing scaffold property tailoring. Herein, we combine these two fields and compare porous Zr-based MOFs UiO-66-NH2(Zr) and UiO-66(Zr) to monoclinic ZrO2 as model colloid hosts with co-immobilized molecular carbon dioxide reduction photocatalyst fac-ReBr(CO)3(4,4′-dcbpy) (dcbpy = dicarboxy-2,2′-bipyridine) and photosensitizer Ru(bpy)2(5,5′-dcbpy)Cl2 (bpy = 2,2′-bipyridine). These host-guest systems demonstrate selective CO2-to-CO reduction in acetonitrile in presence of an electron donor under visible light irradiation, with turnover numbers (TONs) increasing from ZrO2, to UiO-66, and to UiO-66-NH2 in turn. This is attributed to MOF hosts facilitating electron hopping and enhanced CO2 uptake due to their innate porosity. Both of these phenomena are pronounced for UiO-66-NH2(Zr), yielding TONs of 450 which are 2.5 times higher than under MOF-free homogeneous conditions, highlighting synergistic effects between supramolecular photosystem components in dye-sensitized MOFs.

The utilization of renewable energy-driven CO2 conversion technology has garnered considerable attention as a potential remedy for both the energy crisis and climate change. Among various methods, the electrocatalytic CO2 reduction reaction (CO2RR) has received particular focus due to its mild reaction conditions and its ability to produce various valuable products. Specifically, formic acid holds great promise for CO2 electrolysis due to its potential for energy storage and transportation, as well as its commercial viability as indicated by techno-economic assessments. Bi, In, and Sn are several metal catalysts that have been reported for formic acid production, with Bi catalysts demonstrating favorable properties in terms of both cost-effectiveness and selective production of formic acid. However, despite efforts to enhance the intrinsic catalytic activity of Bi through methods such as nanostructuring and alloying, it has yet to achieve the desired level of performance. In light of recent findings by Nam et al. on the ability of a metal-organic framework (MOF) to regulate reaction intermediates for Ag catalyst, resulting in higher CO production, we draw inspiration from MOF's versatility and demonstrate the successful coupling of Bi with UiO-66, a Zr-MOF, to achieve higher CO2 reduction rates and thus increase formic acid production [1]. We synthesized MOF materials, UiO-66 and NH2-functionalized UiO-66 (UiO-66-NH2), and deposited Bi catalysts on the MOF structures using the NaBH4 reduction method, resulting in Bi/UiO-66 and Bi/UiO-66-NH2 samples. To compare the catalytic activity, we also synthesized Bi particle samples using the same method (Bi). Prior to CO2 reduction examination, all electrocatalysts were pre-treated in a 1.0 M KOH solution for 5 minutes, and then CO2 electrolysis was performed in a flow-cell reactor. Among the synthesized samples, Bi/UiO-66 demonstrated excellent CO2 reduction properties, exhibiting about 5 times higher current density (-220 mA/cm2) at an applied potential of -0.7 V vs. the reversible hydrogen electrode (RHE) than Bi alone (-44 mA/cm2), despite the identical electrochemically active surface area (ECSA) for both samples. On the other hand, Bi/UiO-66-NH2 showed an almost identical ECSA-normalized current density compared to Bi/UiO-66, indicating the negligible effect of NH2 functionalization on UiO-66 for CO2RR. Nevertheless, it is evident that the utilization of Zr-MOF (UiO-66) is beneficial in increasing the CO2 conversion rate of metallic Bi catalyst. To comprehend the reason behind the superior catalytic activity exhibited by the Bi/UiO-66 sample, we conducted various characterizations, such as SEM, TEM, FTIR, Raman, and XPS. Our results revealed that the structural evolution of UiO-66 occurs by the formation of carbonate-coordinated Zr-hydroxide during CO2 electrolysis, contributing to the high CO2 reduction current density. Moreover, the disappearance of the carbonate-relevant peak in the C 1s from XPS analysis after the decline in catalytic activity suggests that the carbonate species formed at Zr-MOF site, which is the captured form of CO2 molecules, play a crucial role in efficient CO2 capture and conversion. These findings suggest that Zr-MOF can be used for CO2 capture and conversion with high efficiency. [1] Nam et al., J. Am. Chem. Soc. 2020, 142, 51, 21513–21521.

Polyvinylidene fluoride (PVDF) membranes, enhanced with metal-organic framework (MOF), were fabricated on a non-woven polyethylene terephthalate (PET) support using the non-solvent induced phase inversion (NIPS) method to produce mixed matrix membrane (MMM). Polymer concentration of 10%, 15%, and 20% were used in the study whereas UiO-66(Zr) was used as a MOF filler. The resulting membranes were characterized in terms of their morphology, porosity, wettability, mechanical strength, pure water flux, and gas permeability. Results show that the presence of UiO-66(Zr) filler improved membrane morphology, mechanical strength, and hydrophobicity of MMM as compared to pristine PVDF.

Herein, we report the room temperature aqueous synthesis of the Zr(iv)-based metal-organic framework (MOF) UiO-66 and a series of functionalized derivatives through postsynthetic exchange (PSE) from a perfluorinated UiO-66-F₄.

Les Metal-Organic Frameworks (MOF) sont des matériaux hybrides poreux cristallisés constitués de clusters inorganiques liés les uns aux autres par des ligands organiques. La structure de ces composés offre une porosité très importante et des surfaces spécifiques élevées (jusqu’à plusieurs milliers de m²/g). Mais leur utilisation dans des procédés industriels reste peu développée, notamment à cause d’un manque de connaissance sur leur réactivité vis-à-vis de l’eau. En cours de cette thèse, différentes techniques ont été utilisées afin d’étudier les modifications structurales pouvant intervenir sur l’UiO-66(Zr) en présence de vapeur d’eau : la diffraction des rayons X, l’infrarouge, la mesure de porosité (BET) et la Résonance Magnétique Nucléaires (RMN). Les influences de la longueur du ligand dans l’UiO-67-NH2(Zr) ainsi que la présence de groupement hydrophile dans l’UiO-67-(NH2)2(Zr) ont été étudiées. Nous mettons en avant une stabilité à la vapeur d’eau de certains composés issu de la famille des UiO(Zr) surtout à haute température (200 °C) et une destruction partielle à basse température. De plus, différents enrichissements en 17O de l’UiO-66(Zr) ont été testés permettant l’enregistrement de spectres RMN 17O : enrichissement du ligand par mécanosynthèse, et/ou mise en présence d’eau enrichie. Ces différentes techniques ont permis de mieux comprendre la réactivité des différents sites 17O, et de mettre en avant une certaine labilité des liaisons Zr-O. Enfin des techniques avancées de RMN (basse température et séquence WURST-QCPMG) ont permis de caractériser le cluster de ces composés UiO(Zr) au travers de l’étude du noyau de zirconium-91. De légères modifications du cluster métallique ont pu être pour la première fois observées quand les composés de la famille des UiO(Zr) sont mis en contact avec de la vapeur d’eau. Enfin, des travaux novateurs sur l’élaboration sous la forme de films minces de MOF ont été initiés. Cela doit nous permettre de développer de nouvelles applications dans le domaine de la microélectronique notamment, en fonctionnalisant le substrat utilisé
Metal-Organic Frameworks (MOF) are porous crystallized hybrid materials built from inorganic clusters linked together by organic ligands. The structure of these compounds offers a high porosity and high specific surface areas (up to several thousands of m²/g). But their use at the industrial level is still underdeveloped, most probably because of a lack of knowledge of their reactivity towards water. Different techniques were used to study the structural modifications than can occur when the MOF is in presence of steam water: X-ray diffraction, infrared, porosity measurement (BET) or Nuclear Magnetic Resonance (NMR). The influences of the length of the ligand in the UiO-67-NH2(Zr) as well as the presence of hydrophilic group in the UiO-67-(NH2)2(Zr) were studied. The stability to steam water of some compounds from the family UiO(Zr) is high especially at 200 °C. Even though a partial destruction at low temperature (80°C) is observed. In addition, various 17O enrichments of UiO-66(Zr) were tested allowing the recording of 17O NMR spectra: enrichment of the ligand by mechanosynthesis, and / or the MOF in presence of enriched water. These different techniques have made it possible to better understand the reactivity of the various 17O sites, and to highlight a certain lability of Zr-O bonds. Finally, with advanced NMR techniques (low temperature and WURST-QCPMG sequence) it was possible to characterize the UiO(Zr) compounds through the study of the zirconium-91 isotope. Slight structural modifications of the metallic cluster were then observed. Finally, pioneering work on processing for thin films of MOF has been initiated. This should allow us to develop new applications in the field of microelectronics in particular by functionalizing the substrate

UiO-66 in Zr-MOFs materials stands out in the research of supercapacitors due to its large specific surface, high stability and high heat resistance. In this paper, pure UiO-66 was successfully prepared using solvothermal method, and three PDA/UiO-66 composites with addition mass ratio of UiO-66 and dopamine of 2:1, 3:1 and 4:1 were prepared by autopolymerizing dopamine hydrochloride to form polydopamine at room temperature. The materials’ morphology and structure were examined using SEM, TEM and XRD, and the capacitive performances were analyzed by CV and GCD. The results indicated that the capacitor properties of UiO-66 could be improved to a certain extent with the appropriate amount of polydopamine coating. The PDA/UiO-66 composite with a mass ratio of 2:1 displayed a high specific capacitance of 822.04 F/g at 1 A/g, and maintained good capacity retention even after 4000 charge/discharge cycles in a three-electrode system. These results suggested that the PDA/UiO-66 composite had great potential as a supercapacitor electrode material.