scholarly journals Adsorption of Nitrogen on Mn(II) Metal-organic Framework Nanoparticles

Author(s):  
Idongesıt MBONU
Author(s):  
Idongesit Justina Mbonu ◽  
Olusegun Kehinde Abiola

Adsorption of N2 on mixed ligand benzoic acid and 1, 10-phenanthroline ligands of Mn(II) metal-organic framework (MOF)–nanoparticles were demonstrated. The adsorption capacity and pore size distribution of the synthesized MOF were conducted experimentally by measuring the N2 adsorption isotherm at 77.3 K. The resulting data were fitted to Brunauer-Emmett-Teller (BET), de Boer, Dubinin-Redusbkevich (DR), Banet-Joyner-Halenda (BJH), Horvath-Kawazoe (HK) and Density Functional Theory (DFT) models to describe the adsorptive behaviour of the synthesized nanoparticles. The DSC analysis shows the high chemical stability of this compound. The FT-IR measurement reports present the abundant of highly coordinated functional groups. And the adsorption properties evaluated by different adsorption models compared with existing adsorbent materials suggest Mn-MOF with good thermal stability, high surface area and pore openings, is a promising material for storing gases and energy because at low or high pressures, it can adsorb nitrogen gas due to its large openings.


2019 ◽  
Author(s):  
Simon Krause ◽  
Volodymyr Bon ◽  
Hongchu Du ◽  
Rafal E Dunin-Borkowski ◽  
Ulrich Stoeck ◽  
...  

In this contribution we analyse the influence of adsorption cycling, crystal size, and temperature on the switching behaviour of the flexible Zr-based metal-organic framework DUT-98. We observe a shift in the gate opening pressure upon cycling of adsorption experiments of micro meter-sized crystals and assign this to a fragmentation of the crystals. In a series of modulated syntheses we downsize the average crystal size of DUT-98 crystals from 120 µm to 50 nm and characterize the obtained solids by X-ray diffraction, infrared spectroscopy, as well as scanning and transmission electron microscopy. We analyse the adsorption behaviour by nitrogen and water adsorption at 77 K and 298 K, respectively and show that adsorption-induced flexibility is only observed for micro meter-sized crystals. Nanometer-sized crystals were found to exhibit reversible type I adsorption behaviour upon adsorption of nitrogen and exhibit a crystal-size dependent steep water uptake of up to 20 mmol g-1 at 0.5 p/p 0 with potential for water harvesting and heat pump applications. We furthermore investigate the temperature-induced structural transition by in situ PXRD. At temperatures beyond 110 °C the open pore state of nano meter-sized DUT-98 crystals are found to irreversibly transform in a closed pore state. The connection of crystal fragmentation upon adsorption cycling and the crystal size-dependence of the adsorption-induced flexibility is an important finding for evaluation of these materials in future adsorption-based applications. This work thus extends the limited amount of studies on crystal size effects in flexible MOFs and hopefully motivates further investigations into this field.


2020 ◽  
Vol 142 (36) ◽  
pp. 15235-15239
Author(s):  
Xue Han ◽  
Yuexian Hong ◽  
Yujie Ma ◽  
Wanpeng Lu ◽  
Jiangnan Li ◽  
...  

2018 ◽  
Vol 17 (8) ◽  
pp. 691-696 ◽  
Author(s):  
Xue Han ◽  
Harry G. W. Godfrey ◽  
Lydia Briggs ◽  
Andrew J. Davies ◽  
Yongqiang Cheng ◽  
...  

2021 ◽  
Author(s):  
Jintong Liu ◽  
Jing Huang ◽  
Lei Zhang ◽  
Jianping Lei

We review the general principle of the design and functional modulation of nanoscaled MOF heterostructures, and biomedical applications in enhanced therapy.


2020 ◽  
Author(s):  
Jesse Park ◽  
Brianna Collins ◽  
Lucy Darago ◽  
Tomce Runcevski ◽  
Michael Aubrey ◽  
...  

<b>Materials that combine magnetic order with other desirable physical attributes offer to revolutionize our energy landscape. Indeed, such materials could find transformative applications in spintronics, quantum sensing, low-density magnets, and gas separations. As a result, efforts to design multifunctional magnetic materials have recently moved beyond traditional solid-state materials to metal–organic solids. Among these, metal–organic frameworks in particular bear structures that offer intrinsic porosity, vast chemical and structural programmability, and tunability of electronic properties. Nevertheless, magnetic order within metal–organic frameworks has generally been limited to low temperatures, owing largely to challenges in creating strong magnetic exchange in extended metal–organic solids. Here, we employ the phenomenon of itinerant ferromagnetism to realize magnetic ordering at <i>T</i><sub>C</sub> = 225 K in a mixed-valence chromium(II/III) triazolate compound, representing the highest ferromagnetic ordering temperature yet observed in a metal–organic framework. The itinerant ferromagnetism is shown to proceed via a double-exchange mechanism, the first such observation in any metal–organic material. Critically, this mechanism results in variable-temperature conductivity with barrierless charge transport below <i>T</i><sub>C</sub> and a large negative magnetoresistance of 23% at 5 K. These observations suggest applications for double-exchange-based coordination solids in the emergent fields of magnetoelectrics and spintronics. Taken together, the insights gleaned from these results are expected to provide a blueprint for the design and synthesis of porous materials with synergistic high-temperature magnetic and charge transport properties. </b>


2019 ◽  
Author(s):  
Timothée Stassin ◽  
Ivo Stassen ◽  
Joao Marreiros ◽  
Alexander John Cruz ◽  
Rhea Verbeke ◽  
...  

A simple solvent- and catalyst-free method is presented for the synthesis of the mesoporous metal-organic framework (MOF) MAF-6 (RHO-Zn(eIm)2) based on the reaction of ZnO with 2-ethylimidazole vapor at temperatures ≤ 100 °C. By translating this method to a chemical vapor deposition (CVD) protocol, mesoporous crystalline films could be deposited for the first time entirely from the vapor phase. A combination of PALS and Kr physisorption measurements confirmed the porosity of these MOF-CVD films and the size of the MAF-6 supercages (diam. ~2 nm), in close agreement with powder data and calculations. MAF-6 powders and films were further characterized by XRD, TGA, SEM, FTIR, PDF and EXAFS. The exceptional uptake capacity of the mesoporous MAF-6 in comparison to the microporous ZIF-8 is demonstrated by vapor-phase loading of a molecule larger than the ZIF-8 windows.


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