Articles de revues : « MOF UiO(Zr) »

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Wei, Yuan-Ping, Sizhuo Yang, Peng Wang, Jin-Han Guo, Jier Huang et Wei-Yin Sun. « Iron(iii)-bipyridine incorporated metal–organic frameworks for photocatalytic reduction of CO2 with improved performance ». Dalton Transactions 50, n^o 1 (2021) : 384–90. http://dx.doi.org/10.1039/d0dt03500a.

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Mulyati, Tri Ana, et Fery Eko Pujiono. « Uji Drug Loading Ibuprofen Pada Material UiO-66 (Zr-Metal Organic Framework) ». Jurnal Kimia Riset 4, n^o 2 (31 décembre 2019) : 161. http://dx.doi.org/10.20473/jkr.v4i2.16088.

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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.

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Bhattacharya, Moumita, Kevin J. Chandler, Jackson Geary et Caroline T. Saouma. « The role of leached Zr in the photocatalytic reduction of CO2 to formate by derivatives of UiO-66 metal organic frameworks ». Dalton Transactions 49, n^o 15 (2020) : 4751–57. http://dx.doi.org/10.1039/d0dt00524j.

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Rueda-Navarro, Celia M., Belén Ferrer, Herme G. Baldoví et Sergio Navalón. « Photocatalytic Hydrogen Production from Glycerol Aqueous Solutions as Sustainable Feedstocks Using Zr-Based UiO-66 Materials under Simulated Sunlight Irradiation ». Nanomaterials 12, n^o 21 (28 octobre 2022) : 3808. http://dx.doi.org/10.3390/nano12213808.

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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.

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Nazari, Marziyeh, Abbas Amini, Nathan T. Eden, Mikel C. Duke, Chun Cheng et Matthew R. Hill. « Highly-Efficient Sulfonated UiO-66(Zr) Optical Fiber for Rapid Detection of Trace Levels of Pb2+ ». International Journal of Molecular Sciences 22, n^o 11 (3 juin 2021) : 6053. http://dx.doi.org/10.3390/ijms22116053.

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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.

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Zhang, Qiuyun, Binbin Yang, Yuanyuan Tian, Xianju Yang, Rongfei Yu, Jialu Wang, Taoli Deng et Yutao Zhang. « Fabrication of silicotungstic acid immobilized on Ce-based MOF and embedded in Zr-based MOF matrix for green fatty acid esterification ». Green Processing and Synthesis 11, n^o 1 (1 janvier 2022) : 184–94. http://dx.doi.org/10.1515/gps-2022-0021.

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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.

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Stanley, Philip M., et Julien Warnan. « Molecular Dye-Sensitized Photocatalysis with Metal-Organic Framework and Metal Oxide Colloids for Fuel Production ». Energies 14, n^o 14 (14 juillet 2021) : 4260. http://dx.doi.org/10.3390/en14144260.

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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.

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Song, Jun Tae, Yuta Takaoka, Atsushi Takagaki, Motonori Watanabe et Tatsumi Ishihara. « Synergistic Integration of Zr-MOF (UiO-66) and Bi Electrocatalysts for Enhanced CO₂ Conversion to Formate ». ECS Meeting Abstracts MA2023-02, n^o 47 (22 décembre 2023) : 2382. http://dx.doi.org/10.1149/ma2023-02472382mtgabs.

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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.

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Cementina, John Rhoel, Michael V. Torres, Dante P. Bernabe, Stephen Lirio, Micah Belle Marie Yap Ang et Alvin R. Caparanga. « Fabrication and Characterization of PVDF/UiO-66(Zr) Mixed Matrix Membrane on Non-Woven PET Support ». Materials Science Forum 1005 (août 2020) : 108–15. http://dx.doi.org/10.4028/www.scientific.net/msf.1005.108.

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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.

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Kalaj, Mark, Kathleen E. Prosser et Seth M. Cohen. « Room temperature aqueous synthesis of UiO-66 derivatives via postsynthetic exchange ». Dalton Transactions 49, n^o 26 (2020) : 8841–45. http://dx.doi.org/10.1039/d0dt01939a.

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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.

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Liu, Wei, Fang Wang, Pengcheng Meng et Shuang-Quan Zang. « Sulfonic Acids Supported on UiO-66 as Heterogeneous Catalysts for the Esterification of Fatty Acids for Biodiesel Production ». Catalysts 10, n^o 11 (3 novembre 2020) : 1271. http://dx.doi.org/10.3390/catal10111271.

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Zr-MOF (UiO-66) catalysts PTSA/UiO-66 and MSA/UiO-66 bearing supported sulfonic acids (p-toluenesulfonic acid and methanesulfonic acid, respectively) were prepared through a simple impregnation approach. The UiO-66-supported sulfonic acid catalysts were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, fourier transform infrared spectroscopy (FT-IR) and elemental analysis. The prepared heterogeneous acid catalysts had excellent stability since their crystalline structure was not changed compared with that of the original UiO-66. Zr-MOF MSA/UiO-66 and PTSA/UiO-66 were next successfully used as heterogeneous acid catalysts for the esterification of biomass-derived fatty acids (e.g., palmitic acid, oleic acid) with various alcohols (e.g., methanol, n-butanol). The results demonstrated that both of them had high activity and excellent reusability (more than nine successive cycles) in esterification reactions. Alcohols with higher polarity (e.g., methanol) affected the solid catalyst reusability slightly, while alcohols with moderate or lower polarity (e.g., n-butanol, n-decanol) had no influence. Thus, these developed sulfonic acids-supported metal-organic frameworks (UiO-66) have the potential for use in biodiesel production with excellent reusability.

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SK, Mostakim, Mohammed Rafi Uz Zama Khan, Aniruddha Das, Soutick Nandi, Vishal Trivedi et Shyam Biswas. « A phthalimide-functionalized UiO-66 metal–organic framework for the fluorogenic detection of hydrazine in live cells ». Dalton Transactions 48, n^o 33 (2019) : 12615–21. http://dx.doi.org/10.1039/c9dt02459j.

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Tu, Jiping, Xiaoliang Zeng, Fujian Xu, Xi Wu, Yunfei Tian, Xiandeng Hou et Zhou Long. « Microwave-induced fast incorporation of titanium into UiO-66 metal–organic frameworks for enhanced photocatalytic properties ». Chemical Communications 53, n^o 23 (2017) : 3361–64. http://dx.doi.org/10.1039/c7cc00076f.

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Ding, Zhu, Xiao Min Zhang, Xue Chang, Shuo Wang, Dan-Hong Wang, Ming Hui Zhang et Tian Hao Zhang. « Synergistic Effect between Zr-MOF and Phosphomolybdic Acid with the Promotion of TiF4 Template ». Molecules 25, n^o 20 (13 octobre 2020) : 4673. http://dx.doi.org/10.3390/molecules25204673.

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Metal-Organic Framework (MOF) materials are often modified or functionalized, and then the crystal size and morphology of MOF materials are changed. In the process of preparing UiO-66 confined phosphomolybdic acid (PMA) composites (PU), the TiF4-modified PU (PMA + UiO-66) composite catalyst (TiF4-PU) was successfully synthesized by adding titanium tetrafluoride, and the catalytic desulfurization activity was excellent. Similarly, the reaction mechanism was investigated by means of infrared spectroscopy, Raman spectroscopy, XPS, and UV/Vis spectroscopy. The results show that the addition of TiF4 not only changes the appearance and color of the catalyst, but also changes the valence distribution of the elements in the catalyst. The number of oxygen vacancies in the MOF increases due to the addition of TiF4, and more electrons are transferred from the Zr-MOF to PMA to form more Mo5+, which improved the performance of oxidative desulfurization in comparison. Thus, a stronger strong metal-support interaction (SMSI) effect is observed for TiF4-modified PU catalysts. In addition, the quenching experiment of free radicals shows that ·OH radical is the main active substance in the oxidative desulfurization reaction over TiF4-PU catalyst.

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Tan, Yueyue, Wei Zhang, Yilong Gao, Jianxiang Wu et Bohejin Tang. « Facile synthesis and supercapacitive properties of Zr-metal organic frameworks (UiO-66) ». RSC Advances 5, n^o 23 (2015) : 17601–5. http://dx.doi.org/10.1039/c4ra11896k.

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Faria, Rui G., Diana Julião, Salete S. Balula et Luís Cunha-Silva. « Hf-Based UiO-66 as Adsorptive Compound and Oxidative Catalyst for Denitrogenation Processes ». Compounds 1, n^o 1 (19 janvier 2021) : 3–14. http://dx.doi.org/10.3390/compounds1010002.

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A series of porous metal–organic frameworks (MOFs) of the UiO-66 family, namely UiO-66(Zr), UiO-66(Hf) and UiO-66(Hf)-NH2, prepared by solvothermal procedures were characterized, and their catalytic efficiency for oxidative denitrification (ODN) was investigated for the first time. Sustainable denitrogenation systems combining adsorption and oxidative catalytic capacity were designed using a model diesel containing two distinct nitrogen compounds (NCs) in a solvent-free medium and using an environment-friendly oxidant (H2O2). An efficient adsorptive denitrogenation process was only achieved after long reaction times (24 h): using the Hf-based MOFs, the adsorptive denitrogenation increased from 19% to 79% at 5 to 24 h, while the UiO-66(Zr) reached 76% after 24 h, although the absence of adsorption capacity after 5 h. UiO-66(Hf) and UiO-66(Hf)-NH2 also revealed superior oxidative catalytic denitrogenation than UiO-66(Zr), attaining 97% of efficiency instead of 80%. ODN processes demonstrated to be more effective than the adsorptive denitrogenation, mainly during the first hours of the process. In addition, the metal center in the MOF structure had a larger influence than the presence of the amine-functional groups. Hf-based compounds revealed higher denitrogenation efficiency than the UiO-66(Zr) for a shorter reaction time (5 h).

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Schelling, Marion, Eugenio Otal, Manuela Kim et Juan P. Hinestroza. « Conformal Functionalization of Cotton Fibers via Isoreticular Expansion of UiO-66 Metal-Organic Frameworks ». Coatings 10, n^o 12 (30 novembre 2020) : 1172. http://dx.doi.org/10.3390/coatings10121172.

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We report on the growing of metal-organic frameworks that are isoreticular and isostructural to UiO-66, onto cotton fabrics via a solvothermal method. Four different metal-organic frameworks (MOFs) (UiO-66, UiO-66-NH2, UiO-66-NDC, and UiO-67) were chosen as a case study. The presence of the UiO-based MOFs was confirmed through X-ray diffraction and Scanning Electron Microscopy. We used thermogravimetric analysis to quantify the amount of the MOF loading, which ranged from 0.8% to 2.6% m/m. We also explored the role of ligand size, growth time, and reaction temperature on the conformal coating of cotton fibers with these Zr-based MOFs. Cotton fabrics coated with Zr-based MOFs can find applications as selective filters in aggressive environments due to their enhanced chemical and thermal stabilities.

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Iacomi, Paul, U.-Hwang Lee, Anil H. Valekar, Jong-San Chang et Philip L. Llewellyn. « Investigating the effect of alumina shaping on the sorption properties of promising metal–organic frameworks ». RSC Advances 9, n^o 13 (2019) : 7128–35. http://dx.doi.org/10.1039/c9ra00534j.

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Wei, Lian-Qiang, Jiu-Bin Wei, Fei Yang, Zhi-Wei Li et Hong-Fang Lai. « Preparation of Thiadiazole Modified UiO-68-CdS Composites for RhB Degradation under Visible Light Irradiation ». Crystals 13, n^o 5 (8 mai 2023) : 785. http://dx.doi.org/10.3390/cryst13050785.

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In this paper, the photosensitive Zr-MOF material Thiadiazole-modified UiO-68 (UiO-68N2S) was used to prepare CdS@UiO-68N2S composites by MOF post-reaction. The chemical composition is characterized using PXRD, FT-IR, XPS, SEM, and TGA. Rhodamine B was used as the model dye for photocatalytic degradation to evaluate the performance of CdS@UiO-68N2S under visible light irradiation. Experimental results show that the degradation rate of a 25 mg/L RhB solution (10 mL) reached 94% with 10 mg CdS@UiO-68N2S as a photocatalyst under blue light irradiation in 13 h at room temperature. The mechanism study revealed that O2•− is the reactive oxygen species for the degradation of Rhodamine B. Recycle experiments showed that CdS@UiO-68N2S can be reused for three rounds without a significant reduction of its catalytic function.

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Jia, Xiang-Ze, Qing-Bo Yao, Bin Zhang, Chin-Ping Tan, Xin-An Zeng, Yan-Yan Huang et Qiang Huang. « Design of Recyclable Carboxylic Metal-Organic Framework/Chitosan Aerogels for Oil Bleaching ». Foods 12, n^o 22 (16 novembre 2023) : 4151. http://dx.doi.org/10.3390/foods12224151.

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Novel hierarchical metal-organic framework/chitosan aerogel composites were developed for oil bleaching. UiO-66-COOH-type metal organic frameworks (Zr-MOFs) were synthesized and integrated onto a chitosan matrix with different contents and named MOF-aerogel-1 and MOF-aerogel-2. Due to the compatibility of chitosan, the carboxylic zirconium MOF-aerogels not only maintained the inherent chemical accessibility of UiO-66-COOH, but the unique crystallization and structural characteristics of these MOF nanoparticles were also preserved. Through 3-dimensional reconstructed images, aggregation of the UiO-66-COOH particles was observed in MOF-aerogel-1, while the MOF was homogeneously distributed on the surface of the chitosan lamellae in MOF-aerogel-2. All aerogels, with or without immobilized MOF nanoparticles, were capable of removing carotenoids during oil bleaching. MOF-aerogel-2 showed the most satisfying removal proportions of 26.6%, 36.5%, and 47.2% at 50 °C, 75 °C, and 100 °C, respectively, and its performance was very similar to that of commercial activated clay. The reuse performance of MOF-aerogel-2 was tested, and the results showed its exceptional sustainability for carotenoid removal. These findings suggested the effectiveness of the MOFaerogel for potential utilization in oil bleaching treatments.

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Wang, Chaowei, Zhe Liu, Guangfa Hu, Ruimin Gao et Jianshe Zhao. « Vanadium-substituted heteropolyacids (H3+mPW12−mVmO40) encapsulated in Fe3O4@UiO-66 magnetic core–shell microspheres as excellent catalysts for oxidative desulfurization under oxygen ». New Journal of Chemistry 45, n^o 20 (2021) : 9264–73. http://dx.doi.org/10.1039/d0nj05926a.

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In this study, the novel magnetic core–shell composites Fe₃O₄@UiO-66-HPA, consisting of magnetic Fe₃O₄@UiO-66 and vanadium-substituted Keggin-type heteropolyacid active species supported by Zr-MOF, were prepared via a one-pot method and fully characterized.

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Li, Zhanyong, Aaron W. Peters, Jian Liu, Xuan Zhang, Neil M. Schweitzer, Joseph T. Hupp et Omar K. Farha. « Size effect of the active sites in UiO-66-supported nickel catalysts synthesized via atomic layer deposition for ethylene hydrogenation ». Inorganic Chemistry Frontiers 4, n^o 5 (2017) : 820–24. http://dx.doi.org/10.1039/c7qi00056a.

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Heu, Rina, Mohamed Ateia, Dion Awfa, Patiparn Punyapalakul et Chihiro Yoshimura. « Photocatalytic Degradation of Organic Micropollutants in Water by Zr-MOF/GO Composites ». Journal of Composites Science 4, n^o 2 (12 mai 2020) : 54. http://dx.doi.org/10.3390/jcs4020054.

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Nanocomposites of UiO-66 and graphene oxide (UiO-66_GO) were prepared with different GO contents by a one-step hydrothermal method, and their photocatalytic activities for the degradation of carbamazepine (CBZ) were investigated under ranges of GO loading, catalyst dose, initial pollutant concentration, and solution pH. The UiO-66_GO nanocomposites showed photocatalytic rate constant up to 0.0136 min−1 for CBZ degradation and its high overall removal efficiency (>90%) in 2 h. The photocatalytic rate constant over the UiO-66_GO nanocomposite was about 2.8 and 1.7 times higher than those over pristine GO and UiO-66, respectively. The enhancement of photocatalytic activity by GO was attributed to increased surface area and porosity, improved light absorption, and narrowed band gap. The composite also showed substantial recyclability and stability over five consecutive cycles of photocatalytic degradation. The experimental results indicated that O2●− and OH● are the responsible radicals for photocatalytic degradation, which helped us propose a photocatalytic mechanism for the enhanced CBZ photodegradation. This work provides a reference for the development of GO-based composite photocatalysts and expands the application of UiO-66 as a photocatalyst for the degradation of persistent micropollutants in water.

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Ghosh, Subhrajyoti, et Shyam Biswas. « Ultrafast and nanomolar level detection of H2S in aqueous medium using a functionalized UiO-66 metal–organic framework based fluorescent chemosensor ». Dalton Transactions 50, n^o 33 (2021) : 11631–39. http://dx.doi.org/10.1039/d1dt01456k.

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Nandi, Soutick, Subhrajyoti Ghosh, Mostakim S. K. et Shyam Biswas. « Fluorogenic naked eye “turn-on” sensing of hypochlorous acid by a Zr-based metal organic framework ». New Journal of Chemistry 45, n^o 31 (2021) : 14211–17. http://dx.doi.org/10.1039/d1nj02405a.

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Lammert, M., C. Glißmann et N. Stock. « Tuning the stability of bimetallic Ce(iv)/Zr(iv)-based MOFs with UiO-66 and MOF-808 structures ». Dalton Transactions 46, n^o 8 (2017) : 2425–29. http://dx.doi.org/10.1039/c7dt00259a.

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A series of solid solutions of bimetallic Ce/Zr-UiO-66 and -MOF-808 compounds with a varying ratio of Ce⁴⁺ to Zr⁴⁺ were obtained under mild reaction conditions within 15 min. Samples with Ce ≤20 at% exhibit an enhanced thermal stability, better resistance against acids and smaller particle sizes.

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Andrés, Miguel A., Clemence Sicard, Christian Serre, Olivier Roubeau et Ignacio Gascón. « Ultrathin hydrophobic films based on the metal organic framework UiO-66-COOH(Zr) ». Beilstein Journal of Nanotechnology 10 (6 mars 2019) : 654–65. http://dx.doi.org/10.3762/bjnano.10.65.

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This work reports on the fabrication, optimization and characterization of ultrathin films containing submicrometer particles (sMPs) of the hydrophilic and water stable UiO-66-COOH(Zr) metal organic framework (MOF). MOF particles of ≈200 nm have been synthesized and assembled at the air–water interface by the Langmuir–Blodgett technique. The use of different solvents, mixtures of solvents and surfactants has been investigated in order to improve the stability of MOF dispersions and reduce particle aggregation. The compact MOF/surfactant films containing 10 wt % octadecylphoshonic acid (ODP) have been deposited on substrates of different nature by Langmuir–Blodgett (LB) and Langmuir–Schaefer (LS) methods, showing that the presence of even only one MOF/ODP monolayer can increase the water contact angle of highly hydrophilic substrates such as mica or glass up to 120°. These films were characterized by scanning electron microscopy, grazing incidence X-ray diffraction, Fourier transform infrared spectroscopy and atomic force microscopy, revealing the formation of a continuous film where ODP molecules adopt an almost vertical position and cover MOF particles. Moreover, the presence of MOF particles significantly enhances the surface roughness and allows ultrathin, hydrophobic coverage to be obtained. Finally, it has been shown that the crystallinity and the porosity of the MOF remains almost unaltered in MOF/ODP films.

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Yoo, Dong Kyu, et Sung Hwa Jhung. « Selective CO₂ adsorption at low pressure with a Zr-based UiO-67 metal–organic framework functionalized with aminosilanes ». Journal of Materials Chemistry A 10, n^o 16 (2022) : 8856–65. http://dx.doi.org/10.1039/d1ta09772e.

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MOF UiO-67, although without open metal site, was loaded with aminosilanes for selective CO2 capture. One modified UiO-67 showed a remarkable performance in CO2 adsorption like huge selectivity of 407 which is 163 times that of pristine UiO-67.

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Huang, Yan, Cheng-an Tao, Rui Chen, Liping Sheng et Jianfang Wang. « Comparison of Fabrication Methods of Metal-Organic Framework Optical Thin Films ». Nanomaterials 8, n^o 9 (30 août 2018) : 676. http://dx.doi.org/10.3390/nano8090676.

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Homogeneous metal-organic frameworks (MOFs)-based optical thin films have attracted increasing attention, since they can potentially be used as active components in optical/opt-electrical devices, and how to fabricate MOF thin films with high quality is the premise of practically using them. Herein, five fabrication methods of MOF films are systematically investigated and compared from the aspects of appearance, reflectivity, micro-morphology, surface roughness, and optical properties of the films. The famous robust Zr-based MOF, UiO-66 (UiO = University of Oslo) is chosen as a model, and the five methods are spin-coating, dip-coating, self-assembly, direct growth, and the stepwise layer by layer growth method. This study provides fundamental support for the application of MOFs in the optical field.

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Giannakoudakis, Dimitrios A., et Teresa J. Bandosz. « Building MOF Nanocomposites with Oxidized Graphitic Carbon Nitride Nanospheres : The Effect of Framework Geometry on the Structural Heterogeneity ». Molecules 24, n^o 24 (11 décembre 2019) : 4529. http://dx.doi.org/10.3390/molecules24244529.

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Composite of two MOFs, copper-based Cu-BTC (HKUST-1) and zirconium-based Zr-BDC (UiO-66), with oxidized graphitic carbon nitride nanospheres were synthesized. For comparison, pure MOFs were also obtained. The surface features were analyzed using x-ray diffraction (XRD), sorption of nitrogen, thermal analysis, and scanning electron microscopy (SEM). The incorporation of oxidized g-C3N4 to the Cu-BTC framework caused the formation of a heterogeneous material of a hierarchical pores structure, but a decreased surface area when compared to that of the parent MOF. In the case of UiO-66, functionalized nanospheres were acting as seeds around which the crystals grew. Even though the MOF phases were detected in both materials, the porosity analysis indicated that in the case of Cu-BTC, a collapsed MOF/nonporous and amorphous matter was also present and the MOF phase was more defectous than that in the case of UiO-66. The results suggested different roles of oxidized g-C3N4 during the composite synthesis, depending on the MOF geometry. While spherical units of UiO-66 grew undisturbed around oxidized and spherical g-C3N4, octahedral Cu-BTC units experienced geometrical constraints, leading to more defects, a disturbed growth of the MOF phase, and to the formation of mesopores at the contacts between the spheres and MOF units. The differences in the amounts of CO2 adsorbed between the MOFs and the composites confirm the proposed role of oxidized g-C3N4 in the composite formation.

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Heu, Rina, Mohamed Ateia et Chihiro Yoshimura. « Photocatalytic Nanofiltration Membrane Using Zr-MOF/GO Nanocomposite with High-Flux and Anti-Fouling Properties ». Catalysts 10, n^o 6 (25 juin 2020) : 711. http://dx.doi.org/10.3390/catal10060711.

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Photocatalytic nanofiltration (NF) membranes with enhanced flux and anti-fouling properties were prepared from a layered in situ nanocomposite of metal organic framework (i.e., UiO-66) and graphene oxide (UiO-66_GO) on a polyamide NF membrane using a pressure-assisted self-assembly method. For filtering pure water and humic acid, the composite membrane with a 10% UiO-66_GO loading (UiO-66_GO/NF-10%) showed a higher water flux (up to 63 kg/m2 h bar), flux recovery (80%), and total fouling resistance (33%) than the pristine NF membrane. Physical and chemical characterization revealed that this performance was attributed to improvements in hydrophilicity, porosity, surface smoothness, and charge repulsion. The UiO-66_GO/NF-10% composite membrane exhibited better physical stability with a relatively low mass loss (8.64%) after five washes than the membranes with mass loadings of 5 and 15 wt%. Furthermore, the UiO-66_GO/NF-10% composite membrane exhibited considerable photocatalytic activity under ultraviolet (UV) irradiation (bandgap: 3.45 eV), which reduced irreversible fouling from 20.7% to 2.4% and increased flux recovery to 98%. This study demonstrated that surface modification with the UiO-66_GO nanocomposite produced a high-flux anti-fouling photocatalytic NF membrane, which is promising for water purification.

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Viana, Alexandre M., Susana O. Ribeiro, Baltazar de Castro, Salete S. Balula et Luís Cunha-Silva. « Influence of UiO-66(Zr) Preparation Strategies in Its Catalytic Efficiency for Desulfurization Process ». Materials 12, n^o 18 (17 septembre 2019) : 3009. http://dx.doi.org/10.3390/ma12183009.

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Porous metal-organic framework (MOF) materials UiO-66(Zr) obtained by solvothermal and microwave advanced synthesis (MWAS) procedures were characterized, and their catalytic efficiency was investigated for oxidative desulfurization (ODS) processes using a multicomponent model diesel containing benzothiophene and dibenzothiophene derivatives. The preparation parameters as the cooling time after oven use in the solvothermal procedure, and also the reaction time in the MWAS method seemed to play an important role in the catalytic performance of the UiO-66(Zr) material, as well as in its recycle capacity. The material prepared by the solvothermal procedure with a fast cooling time showed the best catalytic performance (desulfurization efficiency of 99.5% after 3 h). However, the application of the UiO-66(Zr) material prepared by the MWAS method (desulfurization efficiency of 96% after 3 h) conciliated a higher number of advantages, such as shorter reaction time preparation (15 min) and high catalytic activity for a higher number of reaction cycles. The UiO-66(Zr) prepared by the MWAS method was used for the first time in an oxidative desulfurization process, and according to the catalytic results obtained (high recycle capacity and stability) and shorter reaction time preparation, seems to be a promising material for industrial application.

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Klet, Rachel C., Yangyang Liu, Timothy C. Wang, Joseph T. Hupp et Omar K. Farha. « Evaluation of Brønsted acidity and proton topology in Zr- and Hf-based metal–organic frameworks using potentiometric acid–base titration ». Journal of Materials Chemistry A 4, n^o 4 (2016) : 1479–85. http://dx.doi.org/10.1039/c5ta07687k.

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Potentiometric acid–base titration is introduced as a method to evaluate pK_a values (Brønsted acidity) of protons present in the nodes of water stable Zr₆- and Hf₆-based metal–organic frameworks (MOFs), including UiO-type MOFs, NU-1000, and MOF-808.

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Xie, Sijie, Xuan Zhang et Jan Fransaer. « Fast and One-Pot Reductive Deposition of Continuous Uio-66 Films ». ECS Meeting Abstracts MA2022-02, n^o 23 (9 octobre 2022) : 959. http://dx.doi.org/10.1149/ma2022-0223959mtgabs.

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UiO-66 (UiO stands for the University of Olso) film membrane is promising for molecular/ion separations owing to its sub-nano-sized pore apertures and superior chemical stability among the metal-organic framework (MOF) family, but the preparation of it remains difficult and challenging up to now. Here we report a fast and one-pot reductive deposition approach to the high-quality UiO-66 film coatings. In the deposition, the nitrate anions are introduced as pro-bases to accelerate the deprotonation of the ditopic linker-H2BDC (1,4-benzenedicarboxylic acid), which renders the continuous UiO-66 films coating in an hour. Importantly, the morphology of the deposited UiO-66 films can be well-tuned by the molar ratio of the ditopic linker to monotopic modulator because of their completing deprotonation process. The continuous, intergrown, and crystalline UiO-66 films can be obtained at optimized conditions (i.e., deposition temperature at 120 ℃, and the molar ratio of the linker to the modulator of 1:120). Besides, the proposed reductive deposition is also feasible for the fabrication of the analogues of UiO-66 with distinct ligands, like the Zr-fumaric films and Zr-naph (naph is the 1,4-naphthalenedicarboxylic acid) films. These deposited films can be prospective separation mediums for molecular sieving. Figure 1

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Liu, Hui-Lai, Yu Zhang, Xin-Xin Lv, Min-Shu Cui, Kang-Ping Cui, Zheng-Liang Dai, Bei Wang, Rohan Weerasooriya et Xing Chen. « Efficient Degradation of Sulfamethoxazole by Diatomite-Supported Hydroxyl-Modified UIO-66 Photocatalyst after Calcination ». Nanomaterials 13, n^o 24 (11 décembre 2023) : 3116. http://dx.doi.org/10.3390/nano13243116.

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Sulfamethoxazole (SMX) is a widely used antibiotic to treat bacterial infections prevalent among humans and animals. SMX undergoes several transformation pathways in living organisms and external environments. Therefore, the development of efficient remediation methods for treating SMX and its metabolites is needed. We fabricated a photo-Fenton catalyst using an UIO-66 (Zr) metal–organic framework (MOF) dispersed in diatomite by a single-step solvothermal method for hydroxylation (HO-UIO-66). The HO-UIO-66-0/DE-assisted Fenton-like process degraded SMX with 94.7% efficiency; however, HO-UIO-66 (Zr) is not stable. We improved the stability of the catalyst by introducing a calcination step. The calcination temperature is critical to improving the catalytic efficiency of the composite (for example, designated as HO-UIO-66/DE-300 to denote hydroxylated UIO-66 dispersed in diatomite calcined at 300 °C). The degradation of SMX by HO-UIO-66/DE-300 was 93.8% in 120 min with 4 mmol/L H2O2 at pH 3 under visible light radiation. The O1s XPS signatures signify the stability of the catalyst after repeated use for SMX degradation. The electron spin resonance spectral data suggest the role of h+, •OH, •O2−, and 1O2 in SMX degradation routes. The HO-UIO-66/DE-300-assisted Fenton-like process shows potential in degrading pharmaceutical products present in water and wastewater.

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Musho, Terence, et Nianqiang Wu. « Ab initio calculation of electronic charge mobility in metal–organic frameworks ». Physical Chemistry Chemical Physics 17, n^o 39 (2015) : 26160–65. http://dx.doi.org/10.1039/c5cp03920g.

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The electron mobility of a Zr-UiO-66 benzenedicarboxylate (BDC) metal-organic framework (MOF) with three functional designs was investigated using a DFT method in combination with a Boltzmann relaxation time approximation. The results provide evidence of strong control of the charge carrier mobility in functionalized MOFs through manipulation of the majority carrier population.

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Chang, Ziyong, Xiaosha Gong, Liang Zeng, Junlian Wang et Yangge Zhu. « Magnetic Zr-Based Metal-Organic Frameworks : A Highly Efficient Au (III) Trapper for Gold Recycling ». Materials 15, n^o 19 (21 septembre 2022) : 6531. http://dx.doi.org/10.3390/ma15196531.

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In this work, the magnetic Zr-based MOF composites with excellent retrievability were prepared using Fe3O4@SiO2 as the core and UiO–66–NH2 as the shell. Fe3O4@SiO2 core could introduce mesopores and result in capillary condensation in MOF composites, which aggravated with the dosage of Fe3O4@SiO2. The as-synthesized MOF composites could be rapidly retrieved from aqueous solution via magnetic separation in 10 seconds. pH imposed an important effect on Au (III) adsorption by governing the ion exchange and electrostatic interaction between Au (III) anions and adsorbents, and the optimal adsorption happened at pH 7. The adsorption process fitted well with the pseudo-second order kinetics model and Langmuir adsorption model. The maximum adsorption capacity of Au (III) by FSUN–10 and FSUN–50 at 298 K were determined to be 611.18 mg∙g−1 and 463.85 mg∙g−1, respectively. Additionally, Au (III) uptakes increased with temperature. Beyond experiments, the adsorption mechanisms were thoroughly studied through systematic characterization, molecular dynamics simulation (MDS) and density functional theory (DFT) study. It was verified that Au (III) was adsorbed via coordination to hydroxyl and amino groups and was reduced to Au (I) and Au (0) by amino groups. The diffusion coefficient of Au (III) along UiO–66–NH2 was calculated to be 5.8 × 10−5 cm2∙s−1. Moreover, the magnetic Zr-based MOF composites exhibit great industrial value in gold recycling with high adsorption selectivity and good recyclability.

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Ruan, Bo, Huan-Li Liu, Xue-Qing Zhan, Hui Ding, Lei Xie et Fang-Chang Tsai. « Effect of transition metal ions on luminescence of MOFs ». MATEC Web of Conferences 238 (2018) : 05004. http://dx.doi.org/10.1051/matecconf/201823805004.

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Three kinds of metal-organic framework materials (MOF-5, MLI-101(Cr), UiO-66) are synthesized, which are based on transition metal (Zn, Cr, Zr) as the center ions, and terephthalic acid (H2BDC) as organic ligand. At the same time, three kinds of MOFs were characterized and analyzed with X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible absorption spectrometer (UV-Vis), and fluorescence spectrometer (PL). This article analyzes the fluorescence effects of these three MOFs and investigates the role of different transition metal ions in MOF luminescence. The results show that the ionic radii of Zn2 + and Zr4 + are similar, which are 0.074 nm and 0.072 nm, respectively. MOF-5 and UiO-66 have similar fluorescence effects, both of which emit blue-violet light. However, MIL-101 (Cr) fluorescence centers on Cr3 + with an ionic radius of 0.0651 nm emits yellow-green light, which is different from the foregoing MOFs. Therefore, the ionic radius of the transition metal has an important effect on the fluorescence effect of the MOF. For larger ionic radii, the fluorescence of MOF is generally in the blue-violet square region.

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Meng, Xiangshi, Bo Gui, Daqiang Yuan, Matthias Zeller et Cheng Wang. « Mechanized azobenzene-functionalized zirconium metal-organic framework for on-command cargo release ». Science Advances 2, n^o 8 (août 2016) : e1600480. http://dx.doi.org/10.1126/sciadv.1600480.

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Stimuli-responsive metal-organic frameworks (MOFs) have gained increasing attention recently for their potential applications in many areas. We report the design and synthesis of a water-stable zirconium MOF (Zr-MOF) that bears photoresponsive azobenzene groups. This particular MOF can be used as a reservoir for storage of cargo in water, and the cargo-loaded MOF can be further capped to construct a mechanized MOF through the binding of β-cyclodextrin with the azobenzene stalks on the MOF surface. The resulting mechanized MOF has shown on-command cargo release triggered by ultraviolet irradiation or addition of competitive agents without premature release. This study represents a simple approach to the construction of stimuli-responsive mechanized MOFs, and considering mechanized UiO-68-azo made from biocompatible components, this smart system may provide a unique MOF platform for on-command drug delivery in the future.

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Li, Changyun, He Zhang, Xuefei Wang, Qiu-Yan Li, Xinsheng Zhao et Xiao-Jun Wang. « A thiadiazolopyridine-functionalized Zr(iv)-based metal–organic framework for enhanced photocatalytic synthesis of tetrahydroquinolines under visible light ». RSC Advances 12, n^o 3 (2022) : 1638–44. http://dx.doi.org/10.1039/d1ra07363j.

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A photoactive thiadiazolopyridine moiety functionalized UiO-68 isoreticular MOF exhibited an enhanced photocatalytic activity for the synthesis of tetrahydroquinolines between N,N-dimethylanilines and maleimides under visible light.

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Liu, Yong-Liang, Yanqing Di, Fengying Chen, Chunsheng Zhou et Bo Liu. « A pyridyl-decorated Zr-organic framework for enhanced gas separation and CO2 transformation ». Dalton Transactions 50, n^o 11 (2021) : 3848–53. http://dx.doi.org/10.1039/d1dt00198a.

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A stable pyridyl-decorated zirconium MOF, Py-UiO-66, was easily synthesized, and shows selective capture of C₂H₂ and CO₂ rather than CH₄, and high catalytic efficiency in CO₂ cycloaddition.

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Yang, Fan, Weiyang Li et Bohejin Tang. « Facile synthesis of amorphous UiO-66 (Zr-MOF) for supercapacitor application ». Journal of Alloys and Compounds 733 (février 2018) : 8–14. http://dx.doi.org/10.1016/j.jallcom.2017.10.129.

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Huang, Lijin, Man He, Beibei Chen et Bin Hu. « A mercapto functionalized magnetic Zr-MOF by solvent-assisted ligand exchange for Hg2+ removal from water ». Journal of Materials Chemistry A 4, n^o 14 (2016) : 5159–66. http://dx.doi.org/10.1039/c6ta00343e.

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A facile preparation of magnetic MOF composites with flexible mercapto group pendants in their pores is realized through solvent-assisted ligand exchange (SALE) under mild conditions in water, and terephthalate in UIO-66 is replaced with mercaptoacetic acid (MAA).

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Wang, Aoning, Yingjie Zhou, Zhoulu Wang, Miao Chen, Luyi Sun et Xiang Liu. « Titanium incorporated with UiO-66(Zr)-type Metal–Organic Framework (MOF) for photocatalytic application ». RSC Advances 6, n^o 5 (2016) : 3671–79. http://dx.doi.org/10.1039/c5ra24135a.

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Al Amery, Naser, Hussein Rasool Abid, Shaobin Wang et Shaomin Liu. « Lifting removal of cationic dye (methylene blue) from wastewater by improving Zr-MOFs via second metal Al coordination ». Journal of Applied Materials and Technology 2, n^o 2 (8 juillet 2021) : 94–111. http://dx.doi.org/10.31258/jamt.2.2.94-111.

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Metal organic frameworks (MOFs) are frequently used as adsorbents in adsorption processes to remove dyes from effluent produced by the textile industry. Today, dye contaminants have become an important environmental problem. One of these dyes is methylene blue (MB) and its removal from wastewater is a priority because it is persistent and nondegradable. MB is used in many industries although it has potential harmful effects on human and aquatic life and can be considered a hazardous chemical when in wastewater. The present study shows the potential applications for enhanced forms of UiO-66 MOFs, such as UiO-66, UiO-66-10%Al and UiO-66-30%Al. These forms were prepared to remove MB from wastewater using batch experiments. Characterisation of adsorbents were accomplished successfully using Fourier transform infrared, X-ray powder diffraction, Brunauer–Emmett–Teller surface area and thermogravimetric analysis techniques. To investigate equilibrium adsorptive behaviour, Langmuir and Freundlich isotherm models were tested against the experimental data. Based on linear regression correlation coefficient (R2), the Freundlich model described the equilibrium isotherm of MOF/MB better than the Langmuir model. Of all forms of UiO-66 MOF, UiO-66-10%Al had the maximum Langmuir adsorption capacity at 49.26 mg/g. A kinetics study examined pseudo first-order, pseudo second order and Elovich models to determine which could explain the sorption mechanism. While the pseudo second order and Elovich models showed a good fit with the experimental data, the correlation coefficient of the pseudo second-order model was the highest. These results indicate that adsorption of MB is controlled by a chemisorption mechanism. Further, intraparticle diffusion was utilised to describe the adsorption mechanism and determine the rate-limiting steps in the adsorption process.

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Li, Ting, Tian Tian, Fangyuan Chen, Xiang Liu et Xiaohua Zhao. « Pd Nanoparticles Incorporated Within a Zr-Based Metal–Organic Framework/Reduced Graphene Oxide Multifunctional Composite for Efficient Visible-Light-Promoted Benzyl Alcohol Oxidation ». Australian Journal of Chemistry 72, n^o 5 (2019) : 334. http://dx.doi.org/10.1071/ch18387.

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Metal–organic frameworks (MOFs) in photocatalysis oxidation reactions have been arousing great interest because of their unique properties. Zr-based MOFs (mainly 1,4-dicarboxybenzene MOF (UiO-66)) appear to be very attractive candidates. In this study, a Pd@UiO-66/reduced graphene oxide (rGO) nanocomposite was successfully prepared via a facile solvothermal method and was characterised by several techniques, including field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), nitrogen adsorption–desorption isotherms, and photoluminescence (PL) spectroscopy. Subsequently, the as-obtained Pd@UiO-66/rGO composite was used as a photocatalyst for the selective oxidation of benzyl alcohol to benzaldehyde with O2 under visible light irradiation (>420nm); it exhibited superior photocatalytic activity due to the synergistic effect of coupling Pd nanoparticles (NPs) with UiO-66 and rGO. Importantly, the Pd@UiO-66/rGO composite showed high stability and considerable recyclability to preserve most of its initial photocatalytic activity after five cycles of the oxidation reaction.

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Mohamed, Alaa, Elvia P. Valadez Sanchez, Evgenia Bogdanova, Britta Bergfeldt, Ammar Mahmood, Roman V. Ostvald et Tawheed Hashem. « Efficient Fluoride Removal from Aqueous Solution Using Zirconium-Based Composite Nanofiber Membranes ». Membranes 11, n^o 2 (20 février 2021) : 147. http://dx.doi.org/10.3390/membranes11020147.

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Herein, composite nanofiber membranes (CNMs) derived from UiO-66 and UiO-66-NH2 Zr-metal-organic frameworks (MOFs) were successfully prepared, and they exhibited high performance in adsorptive fluoride removal from aqueous media. The resultant CNMs were confirmed using different techniques, such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Brunauer–Emmett–Teller (BET) in addition to Fourier-transform infrared spectroscopy (FTIR). The parameters that govern the fluoride adsorption were evaluated, including adsorbent dose, contact time, and pH value, in addition to initial concentration. The crystalline structures of CNMs exhibited high hydrothermal stability and remained intact after fluoride adsorption. It could also be observed that the adsorbent dose has a significant effect on fluoride removal at high alkaline values. The results show that UiO-66-NH2 CNM exhibited high fluoride removal due to electrostatic interactions that strongly existed between F− and metal sites in MOF in addition to hydrogen bonds formed with MOF amino groups. The fluoride removal efficiency reached 95% under optimal conditions of 20 mg L−1, pH of 8, and 40% adsorbent dose at 60 min. The results revealed that UiO-66-NH2 CNM possesses a high maximum adsorption capacity (95 mg L−1) over UiO-66 CNM (75 mg L−1), which exhibited better fitting with the pseudo-second-order model. Moreover, when the initial fluoride concentration increased from 20 to 100 mg/L, fluoride adsorption decreased by 57% (UiO-66 CNM) and 30% (UiO-66-NH2 CNM) after 60 min. After three cycles, CNM revealed the regeneration ability, demonstrating that UiO-66-NH2 CNMs are auspicious adsorbents for fluoride from an aqueous medium.

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Rowe, Jennifer M., Erin M. Soderstrom, Jie Zhu, Pavel M. Usov et Amanda J. Morris. « Synthesis, characterization, and luminescent properties of two new Zr(IV) metal–organic frameworks based on anthracene derivatives ». Canadian Journal of Chemistry 96, n^o 9 (septembre 2018) : 875–80. http://dx.doi.org/10.1139/cjc-2017-0445.

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Metal–organic frameworks (MOFs) are crystalline materials constructed from metal ions or clusters, connected by multidentate organic ligands. Herein, we describe the synthesis and photophysical properties of two Zr-based, anthracene-containing MOFs, assembled from 2,6-anthracenedicarboxylic acid (2,6-ADCA and 2,6-MOF) and 1,4-anthracenedicarboxylic acid (1,4-ADCA and 1,4-MOF). The 2,6-ADCA analogue formed a highly crystalline octahedral structure that is isostructural with the well-known UiO-67 frameworks. Incorporation of the 1,4-ADCA ligand, on the other hand, resulted in large rod-shaped crystals. Both MOFs exhibit linker-based luminescence. The excited-state properties of the 2,6-MOF and 1,4-MOF were examined using stead-state diffuse reflectance and emission spectroscopies and time-correlated single photon counting (TCSPC) spectroscopy. The photophysical properties of the MOFs are compared with those of the corresponding ligand in solution.

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Wang, Yong-Mei, Xinxin Zhang, Dingyi Yang, Liting Wu, Jiaojiao Zhang, Tianmin Lei et Rusen Yang. « Highly stable metal-organic framework UiO-66-NH₂ for high-performance triboelectric nanogenerators ». Nanotechnology 33, n^o 6 (15 novembre 2021) : 065402. http://dx.doi.org/10.1088/1361-6528/ac32f8.

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Abstract The high porosity, controllable size, high surface area, and chemical versatility of a metal-organic framework (MOF) enable it a good material for a triboelectric nanogenerator (TENG), and some MOFs have been incorporated in the fabrication of TENGs. However, the understanding of effects of MOFs on the energy conversion of a TENG is still lacking, which inhibits the improvement of the performance of MOF-based TENGs. Here, UiO-66-NH2 MOFs were found to significantly increase the power of a TENG and the mechanism was carefully examined. The electron-withdrawing (EW) ability of Zr-based UiO-66-family MOFs was enhanced by designing the amino functionalized 1,4-terephthalic acid (1,4-BDC) as ligand. The chemically modified UiO-66-NH2 was found to increase the surface roughness and surface potential of a composite film with MOFs embedded in polydimethylsiloxane (PDMS) matrix. Thus the total charges due to the contact electrification increased significantly. The composite-based TENG was found to be very durable and its output voltage and current were 4 times and 60 times higher than that of a PDMS-based TENG. This work revealed an effective strategy to design MOFs with excellent EW abilities for high-performance TENGs.

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Jin, Yuning, Danping Wu, Na Ma et Wei Dai. « Well-design and synthesis of a water- and heat-resistant UiO-67@CNTs composite for Congo red efficient capture ». Water Science and Technology 85, n^o 5 (16 février 2022) : 1636–47. http://dx.doi.org/10.2166/wst.2022.062.

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Abstract MOFs (metal-organic frameworks) significantly suffer from water- and heat instable issues, restricting their practical application, such as the capture of hazardous anionic dyes (e.g. Congo red, CR) from water. In the present contribution, a series of novel composites (UiO-67@CNTs) composed of microporous UiO-67 (Zr6O4(OH)4(CO2)12) and mesoporous CNTs (carbon nanotubes) have been innovatively synthesized by an in-situ hydrothermal reaction strategy. This UiO-67@CNT impressively retains structural integrity whether contacted with strong acid, distilled water, and strong alkali conditions even for 20 days. Due to the existence of CNT, its heat stability can reach up to 480 °C, which is superior to that of UiO-67. Open Zr(IV) sites, mesoporous, and high surface area in the structure of UiO-67@CNTs play associative effects for CR capture ability. CR uptakes over (5.0)UiO-67@CNTs can reach 1024 mg/g, exceeding some other previous adsorbents in literature. Importantly, UiO-67@CNTs could retain a remarkable CR capture ability even after the fifth cycle. This work expands views for water-heat resistant MOF-based composite with excellent ability of CR capture.

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