A nanosized metal–organic framework with small pores for kinetic xenon separation

2018 ◽  
Vol 6 (25) ◽  
pp. 11797-11803 ◽  
Author(s):  
Guangli Yu ◽  
Yueqiao Liu ◽  
Xiaoqin Zou ◽  
Nian Zhao ◽  
Huazhen Rong ◽  
...  
Keyword(s):  
Crystal Size ◽  
Metal Organic Framework ◽  
Prepared Material ◽  
Metal Organic ◽  
Organic Framework

The crystal size of CaSDB metal–organic framework has been engineered down to nanoscale by an additive-assisted method. The as-prepared material has exhibited superior xenon capture performance in terms of fast xenon uptake and good selectivity for xenon over krypton.

scholarly journals The impact of crystal size and temperature on the adsorption-induced flexibility of the Zr-based metal–organic framework DUT-98

2019 ◽  
Vol 10 ◽  
pp. 1737-1744 ◽  
Author(s):  
Simon Krause ◽  
Volodymyr Bon ◽  
Hongchu Du ◽  
Rafal E Dunin-Borkowski ◽  
Ulrich Stoeck ◽  
...  
Keyword(s):  
Crystal Size ◽  
Metal Organic Framework ◽  
Adsorption Behavior ◽  
Switching Behavior ◽  
Type I ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Organic ◽  
The Impact ◽  
Organic Framework

In this contribution we analyze the influence of adsorption cycling, crystal size, and temperature on the switching behavior of the flexible Zr-based metal–organic framework DUT-98. We observe a shift in the gate-opening pressure upon cycling of adsorption experiments for micrometer-sized crystals and assign this to a fragmentation of the crystals. In a series of samples, the average crystal size of DUT-98 crystals was varied from 120 µm to 50 nm and the obtained solids were characterized by X-ray diffraction, infrared spectroscopy, as well as scanning and transmission electron microscopy. We analyzed the adsorption behavior by nitrogen and water adsorption at 77 K and 298 K, respectively, and show that adsorption-induced flexibility is only observed for micrometer-sized crystals. Nanometer-sized crystals were found to exhibit reversible type I adsorption behavior 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 powder X-ray diffraction. At temperatures beyond 110 °C, the open-pore state of the nanometer-sized DUT-98 crystals is found to irreversibly transform to 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 in this field.

Fine tuning of the metal–organic framework Cu3(BTC)2 HKUST-1 crystal size in the 100 nm to 5 micron range

2012 ◽  
Vol 22 (27) ◽  
pp. 13742 ◽  
Author(s):  
Lik H. Wee ◽  
Martin R. Lohe ◽  
Nikki Janssens ◽  
Stefan Kaskel ◽  
Johan A. Martens
Keyword(s):  
Crystal Size ◽  
Metal Organic Framework ◽  
Fine Tuning ◽  
Metal Organic ◽  
Organic Framework

scholarly journals Hyperpolarized Xe NMR signal advancement by metal-organic framework entrapment in aqueous solution

2020 ◽  
Vol 117 (30) ◽  
pp. 17558-17563
Author(s):  
Qingbin Zeng ◽  
Binglin Bie ◽  
Qianni Guo ◽  
Yaping Yuan ◽  
Qi Han ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Crystal Size ◽  
Chemical Exchange ◽  
Metal Organic Framework ◽  
Chemical Exchange Saturation Transfer ◽  
Application Area ◽  
Saturation Transfer ◽  
Metal Organic ◽  
Organic Framework

We report hyperpolarized Xe signal advancement by metal-organic framework (MOF) entrapment (Hyper-SAME) in aqueous solution. The129Xe NMR signal is drastically promoted by entrapping the Xe into the pores of MOFs. The chemical shift of entrapped129Xe is clearly distinguishable from that of free129Xe in water, due to the surface and pore environment of MOFs. The influences from the crystal size of MOFs and their concentration in water are studied. A zinc imidazole MOF, zeolitic imidazole framework-8 (ZIF-8), with particle size of 110 nm at a concentration of 100 mg/mL, was used to give an NMR signal with intensity four times that of free129Xe in water. Additionally, Hyper-SAME is compatible with hyperpolarized129Xe chemical exchange saturation transfer. The129Xe NMR signal can be amplified further by combining the two techniques. More importantly, Hyper-SAME provides a way to make detection of hyperpolarized129Xe in aqueous solution convenient and broadens the application area of MOFs.

scholarly journals The impact of crystal size and temperature on the adsorption-induced flexibility of the Zr-based metal-organic framework DUT-98

2019 ◽  
Author(s):  
Simon Krause ◽  
Volodymyr Bon ◽  
Hongchu Du ◽  
Rafal E Dunin-Borkowski ◽  
Ulrich Stoeck ◽  
...  
Keyword(s):  
Crystal Size ◽  
Metal Organic Framework ◽  
Type I ◽  
Adsorption Behaviour ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Adsorption Of Nitrogen ◽  
Metal Organic ◽  
The Impact ◽  
Organic Framework

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.

scholarly journals Testing Metal–Organic Framework Catalysts in a Microreactor for Ethyl Paraoxon Hydrolysis

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1159
Author(s):  
Palani Elumalai ◽  
Nagat Elrefaei ◽  
Wenmiao Chen ◽  
Ma’moun Al-Rawashdeh ◽  
Sherzod T. Madrahimov
Keyword(s):  
Crystal Size ◽  
Metal Organic Framework ◽  
Catalyst Stability ◽  
Reaction Yield ◽  
Process Conditions ◽  
Chemical Agent ◽  
Testing Metal ◽  
Metal Organic ◽  
The Impact ◽  
Organic Framework

We explored the practical advantages and limitations of applying a UiO-66-based metal–organic framework (MOF) catalyst in a flow microreactor demonstrated by the catalytic hydrolysis of ethyl paraoxon, an organophosphorus chemical agent. The influences of the following factors on the reaction yield were investigated: a) catalyst properties such as crystal size (14, 200, and 540 nm), functionality (NH2 group), and particle size, and b) process conditions: temperature (20, 40, and 60 °C), space times, and concentration of the substrate. In addition, long-term catalyst stability was tested with an 18 h continuous run. We found that tableting and sieving is a viable method to obtain MOF particles of a suitable size to be successfully screened under flow conditions in a microreactor. This method was used successfully to study the effects of crystal size, functionality, temperature, reagent concentration, and residence time. Catalyst particles with a sieved fraction between 125 and 250 µm were found to be optimal. A smaller sieved fraction size showed a major limitation due to the very high pressure drop. The low apparent activation energy indicated that internal mass transfer may exist. A dedicated separate study is required to assess the impact of pore diffusion and site accessibility.

Selective CO2 adsorption and theoretical simulation of a stable Co(ii)-based metal–organic framework with tunable crystal size

CrystEngComm ◽  
2019 ◽  
Vol 21 (10) ◽  
pp. 1564-1569 ◽  
Author(s):  
Bo-Wen Qin ◽  
Bao-Lei Zhou ◽  
Zheng Cui ◽  
Lei Zhou ◽  
Xiao-Ying Zhang ◽  
...  
Keyword(s):  
Crystal Size ◽  
Co2 Adsorption ◽  
Metal Organic Framework ◽  
Design Approach ◽  
Theoretical Simulation ◽  
Metal Organic ◽  
Organic Framework

A stable Co(ii)-MOF shows selective CO2 adsorption and high H2 uptake. The simulations of sorption confirm this reasonable design approach.

Multifunctional metal–organic framework heterostructures for enhanced cancer therapy

2021 ◽  
Author(s):  
Jintong Liu ◽  
Jing Huang ◽  
Lei Zhang ◽  
Jianping Lei
Keyword(s):  
Cancer Therapy ◽  
General Principle ◽  
Biomedical Applications ◽  
Metal Organic Framework ◽  
Metal Organic ◽  
Functional Modulation ◽  
Organic Framework

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

Magnetic Ordering via Itinerant Ferromagnetism in a Metal-Organic Framework

2020 ◽  
Author(s):  
Jesse Park ◽  
Brianna Collins ◽  
Lucy Darago ◽  
Tomce Runcevski ◽  
Michael Aubrey ◽  
...  
Keyword(s):  
Charge Transport ◽  
Magnetic Order ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Magnetic Ordering ◽  
Double Exchange ◽  
Itinerant Ferromagnetism ◽  
Organic Solids ◽  
Metal Organic ◽  
Organic Framework

<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>

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