Fluoride sensing performance of fluorescent NH2-MIL-53(Al): 2D Nanosheets vs. 3D Bulk

2021 ◽  
Author(s):  
Zixuan Li ◽  
Deyi Zhan ◽  
Abdul Saeed ◽  
Nanjing Zhao ◽  
Junfeng Wang ◽  
...  

Due to the ultra-thin morphology, larger specific surface area and more exposed active sites, two-dimensional (2D) metal-organic frameworks (MOFs) nanosheets can break the limitations of three-dimensional (3D) MOFs in sensitivity,...

Author(s):  
Chenyu Liu ◽  
Haitong Wei ◽  
Yanhui Gao ◽  
Ning Wang ◽  
Xiaoying Yuan ◽  
...  

Abstract Metal-Organic Frameworks (MOFs) have unique properties and stable structure, which have been widely used as templates/precursors to prepare well-developed pore structure and high specific surface area materials. In this article, an innovative and facile method of crystal reorganization was designed by using MOFs as sacrificial templates to prepare LDH nano-layer sheet structure through a pseudomorphic conversion process under alkaline conditions. The obtained CoMn-LDH and CoFe-LDH catalysts broke the ligand of MOFs and reorganized the structure on the basis of retaining a high specific surface area and a large number of pores, which have higher specific surface area and well-developed pore structure than LDH catalysts prepared by traditional methods, and thus provide more active sites to activate PMS. Due to the unique framework structure of MOFs, the MOF derived CoMn-LDH and CoFe-LDH catalysts could provide more active sites to activate PMS, and achieve a 2, 4-dichlorophenol (2, 4-DCP) degradation of 99.3% and 99.2% within 20 min, respectively. Besides, the two LDH catalysts displayed excellent degradation performance for bisphenol A (BPA), ciprofloxacin (CIP) and 2, 4-dichlorophenoxyacetic acid (2, 4-D). XPS indicated that the valence state transformation of metal elements participated in PMS activation. EPR manifested sulfate radical () and singlet oxygen (1O2) were the main species for degrading pollutants. In addition, after the three-cycle experiment, the CoMn-LDH and CoFe-LDH catalysts also showed long-term stability with a slight activity decrease in the third cycle. The phytotoxicity assessment determined by the germination of mung beans proved that PMS activation by MOFs-derived LDH catalyst can basically eliminate the phytotoxicity of 2, 4-D solution. This research not only developed high-activity LDH catalysts for PMS activation, but also expanded the environmental applications of MOFs derivants.


CrystEngComm ◽  
2021 ◽  
Author(s):  
Qing Luo ◽  
Zhen Ding ◽  
Huamin Sun ◽  
Zhen Cheng ◽  
Naien SHI ◽  
...  

Ultrathin two-dimensional (2D) metal-organic framework (MOF) nanosheets are prosperous advanced materials due to their particularly thin thickness and exposed active sites. The difficulty in the controlled synthesis of 2D MOF...


2022 ◽  
Author(s):  
Kainan Li ◽  
Ke Zheng ◽  
Zhifang Zhang ◽  
Kuan Li ◽  
Ziyao Bian ◽  
...  

Abstract Construction of metal selenides with a large specific surface area and a hollow structure is one of the effective methods to improve the electrochemical performance of supercapacitors. However, the nano-material easily agglomerates due to the lack of support, resulting in the loss of electrochemical performance. Herein, we successfully design a three-dimensional graphene (3DG) encapsulation-protected hollow nanoboxes (CoSe2-SnSe2) composite aerogel (3DG/CoSe2-SnSe2) via a co-precipitation method coupled with self-assembly route, followed by a high temperature selenidation strategy. The obtained aerogel possesses porous 3DG conductive network, large specific surface area and plenty of reactive active sites. It could be used as a flexible and binder-free electrode after a facile mechanical compression process, which provided a high specific capacitance of 460 F g-1 at 0.5 A g-1, good rate capability of 212.7 F g-1 at 10 A g-1, and excellent cycle stability due to the fast electron/ion transfer and electrolyte diffusion. With the as-prepared 3DG/CoSe2-SnSe2 as positive electrodes and the AC (activated carbon) as negative electrodes, an asymmetric supercapacitor (3DG/CoSe2-SnSe2//AC) was fabricated, which delivered a high specific capacity of 38 F g-1 at 1A g-1 and an energy density of 11.89 W h kg-1 at 749.9 W kg-1, as well as a capacitance retention of 91.1% after 3000 cycles. This work provides a new method for preparing electrode material.


CrystEngComm ◽  
2021 ◽  
Author(s):  
Jiaqi Wang ◽  
Yiling Quan ◽  
Guoxiang Wang ◽  
Dazhi Wang ◽  
Jie Xiao ◽  
...  

Metal–organic frameworks (MOFs) attracted considerable attention through their large specific surface area and excellent adjustable voids. A one-step solvothermal method is proposed herein to fabricate the 3D hollow cage copper-cobalt...


2012 ◽  
Vol 427 ◽  
pp. 123-127
Author(s):  
Yuan Hui Ma ◽  
Lei Zhang ◽  
Cheng Chun Tang

The nanoporous metal-organic frameworks were synthesized under solvothermal conditions using organic solvent dimethylformamide. The samples were characterized by XRD, SEM, TGA, FT-IR and specific surface area for their properties difference. When the reaction temperature rises, the particle size becomes larger. All TGA curves are the basically same, the framework structure begins to be destroyed from 500°C up to around 600°C. The metal-organic frameworks accepted at reaction temperature 190°C have larger specific surface area and better structure stability.


2018 ◽  
Vol 6 (15) ◽  
pp. 6130-6154 ◽  
Author(s):  
Haolin Zhu ◽  
Dingxin Liu ◽  
Dianting Zou ◽  
Jianyong Zhang

Since the discovery of metal–organic frameworks (MOFs), covalent–organic frameworks (COFs) and zeolite–imidazole frameworks (ZIFs), many of their outstanding properties have been explored such as their large specific surface area, significant gas adsorption, and high catalytic activity.


2014 ◽  
Vol 70 (5) ◽  
pp. 502-507
Author(s):  
Hong-Jie Fan ◽  
Qian-Qian Xu ◽  
Tie-Zhen Ren ◽  
Xiang-Ying Xing ◽  
Kirsten E. Christensen

Two novel polymers exhibiting metal–organic frameworks (MOFs) have been synthesized by the combination of a metal ion with a benzene-1,3,5-tricarboxylate ligand (BTC) and 1,10-phenanthroline (phen) under hydrothermal conditions. The first compound, poly[[(μ4-benzene-1,3,5-tricarboxylato-κ4 O:O′:O′′:O′′′)(μ-hydroxido-κ2 O:O)bis(1,10-phenanthroline-κ2 N,N′)dizinc(II)] 0.32-hydrate], {[Zn2(C9H3O6)(OH)(C12H8N2)2]·0.32H2O} n , denoted Zn–MOF, forms a two-dimensional network in which a binuclear Zn2 cluster serves as a 3-connecting node; the BTC trianion also acts as a 3-connecting centre. The overall topology is that of a 63 net. The phen ligands serve as appendages to the network and interdigitate with phen ligands belonging to adjacent parallel sheets. The second compound, poly[[(μ6-benzene-1,3,5-tricarboxylato-κ7 O 1,O 1′:O 1:O 3:O 3′:O 5:O 5′)(μ3-hydroxido-κ2 O:O:O)(1,10-phenanthroline-κ2 N,N′)dimanganese(II)] 1.26-hydrate], {[Mn2(C9H3O6)(OH)(C12H8N2)]·1.26H2O} n , denoted Mn–MOF, exists as a three-dimensional network in which an Mn4 cluster serves as a 6-connecting unit, while the BTC trianion again plays the role of a 3-connecting centre. The overall topology is that of the rutile net. Phen ligands act as appendages to the network and form the `S-shaped' packing mode.


2019 ◽  
Vol 9 (12) ◽  
pp. 2427 ◽  
Author(s):  
Jun-Hong Li ◽  
Yi-Sen Wang ◽  
Yu-Chuan Chen ◽  
Chung-Wei Kung

Metal–organic frameworks (MOFs) are a class of porous materials constructed from metal-rich inorganic nodes and organic linkers. Because of their regular porosity in microporous or mesoporous scale and periodic intra-framework functionality, three-dimensional array of high-density and well-separated active sites can be built in various MOFs; such characteristics render MOFs attractive porous supports for a range of catalytic applications. Furthermore, the electrochemically addressable thin films of such MOF materials are reasonably considered as attractive candidates for electrocatalysis and relevant applications. Although it still constitutes an emerging subfield, the use of MOFs and relevant materials for electrocatalytic applications has attracted much attention in recent years. In this review, we aim to focus on the limitations and commonly seen issues for utilizing MOFs in electrocatalysis and the strategies to overcome these challenges. The research efforts on utilizing MOFs in a range of electrocatalytic applications are also highlighted.


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