scholarly journals An in Situ Crystal Growth of Metal Organic Frameworks-5 on Electrospun PVA Nanofibers

2018 ◽  
Vol 18 (3) ◽  
pp. 308-313 ◽  
Author(s):  
Hanen Talmoudi ◽  
Nabyl Khenoussi ◽  
Dominique Adolphe ◽  
Ayoub Haj Said ◽  
Laurence Schacher

Abstract In this study, a simple, general and straightforward method for growing metal-organic frameworks (MOFs) crystals directly on nanofibers is presented. A chelating polymer was first blent with metal cation and then electrospun. The obtained nanofibers were immersed in a linker solution. Metal cations were released and the metal-organic frameworks crystals were grown on the fibers’ surface. In this work, this method was tested with polyvinyl alcohol as chelating polymer, Zn2+ as metal cation and Terephthalic acid as linker. The pair cation/linker corresponds to the MOF-5. The latter is a robust metal organic framework formed from Zn4O nodes with 1,4-benzodicarboxylic acid struts between the nodes. SEM images revealed that the MOF-5 nanocrystals have grown along the PVA/Zn2+ nanofibers that served as the crystals’ growth template by providing the Zn2+ ions. This result was also confirmed by infrared spectroscopy, which indicates the presence of characteristic bands of MOF-5 in the modified nanofibers spectrum. Moreover, the X-ray diffraction showed that MOF-5 material was well crystallized on the nanofibers surface according to a cubic symmetry with a space group Fm-3m and a lattice constant a = 25.8849 Å.

2020 ◽  
Vol 75 (8) ◽  
pp. 727-732
Author(s):  
Chen Zhang ◽  
Jian-Qing Tao

AbstractA new Cu(II) metal-organic framework, [Cu(L)(OBA)·H2O]n (1) [H2OBA = 4,4′-oxybis(benzoic acid), L = 3,5-di(1H-benzimidazol-1-yl)pyridine] was hydrothermally synthesized and characterized through IR spectroscopy, elemental and thermal analysis and single-crystal X-ray diffraction. Complex 1 is a four-connected uni-nodal 2D net with a (44·62) topology which shows an emission centered at λ ∼393 nm upon excitation at λ = 245 nm. Moreover, complex 1 possesses high photocatalytic activities for the decomposition of Rhodamine B (RhB) under UV light irradiation.


Author(s):  
Stephen J. I. Shearan ◽  
Jannick Jacobsen ◽  
Ferdinando Costantino ◽  
Roberto D’Amato ◽  
Dmitri Novikov ◽  
...  

2015 ◽  
Vol 17 (26) ◽  
pp. 17471-17479 ◽  
Author(s):  
Volodymyr Bon ◽  
Nicole Klein ◽  
Irena Senkovska ◽  
Andreas Heerwig ◽  
Jürgen Getzschmann ◽  
...  

The “gate opening” mechanism in flexible MOF Ni2(2,6-ndc)2dabco was elucidated in detail.


2020 ◽  
Author(s):  
Bikash Garai ◽  
Volodymyr Bon ◽  
Francesco Walenszus ◽  
Azat Khadiev ◽  
Dmitri Novikov ◽  
...  

Variation in the metal centres of M-M paddle-wheel SBU results in the formation of isostructural DUT-49(M) frameworks. However, the porosity of the framework was found to be different for each of the structures. While a high and moderate porosity was obtained for DUT-49(Cu) and DUT-49(Ni), respectively, other members of the series [DUT-49(M); M= Mn, Fe, Co, Zn, Cd] show very low porosity and shapes of the adsorption isotherms which is not expected for op phases of these MOFs. Investigation on those MOFs revealed that those frameworks undergo structural collapse during the solvent removal at the activation step. Thus, herein, we aimed to study the detailed structural transformations that are possibly occurring during the removal of the subcritical fluid from the framework.


2020 ◽  
Author(s):  
Stephen Shearan ◽  
Jannick Jacobsen ◽  
Ferdinando Costantino ◽  
Roberto D’Amato ◽  
Dmitri Novikov ◽  
...  

We report on the results of a thorough <i>in situ</i> synchrotron powder X-ray diffraction study of the crystallisation in aqueous medium of two recently discovered perfluorinated Ce(IV)-based metal-organic frameworks (MOFs), analogues of the already well investigated Zr(IV)-based UiO-66 and MIL-140A, namely, F4_UiO-66(Ce) and F4_MIL-140A(Ce). The two MOFs were originally obtained in pure form in similar conditions, using ammonium cerium nitrate and tetrafluoroterephthalic acid as building blocks, and small variations of the reaction parameters were found to yield mixed phases. Here, we investigate the crystallisation of these compounds <i>in situ</i> in a wide range of conditions, varying parameters such as temperature, amount of the protonation modulator nitric acid (HNO<sub>3</sub>) and amount of the coordination modulator acetic acid (AcOH). When only HNO<sub>3</sub> is present in the reaction environment, F4_MIL-140A(Ce) is obtained as a pure phase. Heating preferentially accelerates nucleation, which becomes rate determining below 57 °C, whereas the modulator influences nucleation and crystal growth to a similar extent. Upon addition of AcOH to the system, alongside HNO<sub>3</sub>, mixed-phased products, consisting of F4_MIL-140A(Ce) and F4_UiO-66(Ce), are obtained. In these conditions, F4_UiO-66(Ce) is always formed faster and no interconversion between the two phases occurs. In the case of F4_UiO-66(Ce), crystal growth is always the rate determining step. An increase in the amount of HNO<sub>3</sub> slows down both nucleation and growth rates for F4_MIL-140A(Ce), whereas nucleation is mainly affected for F4_UiO-66(Ce). In addition, a higher amount HNO<sub>3</sub> favours the formation of F4_MIL-140A(Ce). Similarly, increasing the amount of AcOH leads to slowing down of the nucleation and growth rate, but favours the formation of F4_UiO-66(Ce). The pure F4_UiO-66(Ce) phase could also be obtained when using larger amounts of AcOH in the presence of minimal HNO<sub>3</sub>. Based on these <i>in situ</i> results, a new optimised route to achieving a pure, high quality F4_MIL-140A(Ce) phase in mild conditions (60 °C, 1 h) is also identified.


2020 ◽  
Vol 8 (12) ◽  
pp. 6034-6040 ◽  
Author(s):  
Yanan Wang ◽  
Wenlong Zhen ◽  
Yiqing Zeng ◽  
Shipeng Wan ◽  
Haiwei Guo ◽  
...  

A series of Zr-porphyrin metal–organic framework (Zr-PMOF)/ultrathin g-C3N4 (UCN) heterostructure photocatalysts, as stable and efficient catalysts for the photoreduction of CO2, have been fabricated via a facile in situ hydrothermal self-assembly method.


Nanoscale ◽  
2019 ◽  
Vol 11 (15) ◽  
pp. 7347-7357 ◽  
Author(s):  
Lei Wang ◽  
Zhennan Huang ◽  
Bo Wang ◽  
Hao Luo ◽  
Meng Cheng ◽  
...  

Titanium-based metal–organic frameworks have been used as an in situ etching template for the self-assembly of graphene oxide to construct NaTi2(PO4)3-rGO composite.


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