scholarly journals Hypergolic zeolitic imidazolate frameworks (ZIFs) as next-generation solid fuels: Unlocking the latent energetic behavior of ZIFs

2019 ◽  
Vol 5 (4) ◽  
pp. eaav9044 ◽  
Author(s):  
H. M. Titi ◽  
J. M. Marrett ◽  
G. Dayaker ◽  
M. Arhangelskis ◽  
C. Mottillo ◽  
...  

Hypergolic materials, capable of spontaneous ignition upon contact with an external oxidizer, are of critical importance as fuels and propellants in aerospace applications (e.g., rockets and spacecraft). Currently used hypergolic fuels are highly energetic, toxic, and carcinogenic hydrazine derivatives, inspiring the search for cleaner and safer hypergols. Here, we demonstrate the first strategy to design hypergolic behavior within a metal-organic framework (MOF) platform, by using simple “trigger” functionalities to unlock the latent and generally not recognized energetic properties of zeolitic imidazolate frameworks, a popular class of MOFs. The herein presented six hypergolic MOFs, based on zinc, cobalt, and cadmium, illustrate a uniquely modular platform to develop hypergols free of highly energetic or carcinogenic components, in which varying the metal and linker components enables the modulation of ignition and combustion properties, resulting in excellent hypergolic response evident by ultrashort ignition delays as low as 2 ms.

2018 ◽  
Author(s):  
Tomislav Friscic ◽  
Hatem M. Titi ◽  
Mihails Arhangelskis ◽  
Dayaker Gandrath ◽  
Cristina Mottillo ◽  
...  

We present the first strategy to induce hypergolic behavior, i.e. spontaneous ignition and combustion in contact with an external oxidizer, into metal-organic frameworks (MOFs). The strategy uses trigger acetylene or vinyl substituents to unlock the latent hypergolic properties of linkers in zeolitic imidazolate frameworks, illustrated here by six hypergolic MOFs of zinc, cobalt and cadmium. Varying the metal and linker enabled the modulation of ignition and combustion properties, leading to ultrashort ignition delays (down to 2 ms), on par with popular propellants, but without requiring highly energetic or carcinogenic hydrazine components found in conventional hypergols.<br>


2018 ◽  
Author(s):  
Tomislav Friscic ◽  
Hatem M. Titi ◽  
Mihails Arhangelskis ◽  
Dayaker Gandrath ◽  
Cristina Mottillo ◽  
...  

We present the first strategy to induce hypergolic behavior, i.e. spontaneous ignition and combustion in contact with an external oxidizer, into metal-organic frameworks (MOFs). The strategy uses trigger acetylene or vinyl substituents to unlock the latent hypergolic properties of linkers in zeolitic imidazolate frameworks, illustrated here by six hypergolic MOFs of zinc, cobalt and cadmium. Varying the metal and linker enabled the modulation of ignition and combustion properties, leading to ultrashort ignition delays (down to 2 ms), on par with popular propellants, but without requiring highly energetic or carcinogenic hydrazine components found in conventional hypergols.<br>


Pharmaceutics ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 463 ◽  
Author(s):  
Wu ◽  
Fu ◽  
Zhou ◽  
Wang ◽  
Feng ◽  
...  

Rapid increase of antimicrobial resistance has become an urgent threat to global public health. In this research, since photothermal therapy is a potential antibacterial strategy, which is less likely to cause resistance, a metal–organic framework-based chemo-photothermal combinational system was constructed. Zeolitic imidazolate frameworks-8 (ZIF-8), a porous carrier with unique features such as high loading and pH-sensitive degradation, was synthesized, and then encapsulated photothermal agent indocyanine green (ICG). First, ICG with improved stability in ZIF-8 (ZIF-8-ICG) can effectively produce heat in response to NIR laser irradiation for precise, rapid, and efficient photothermal bacterial ablation. Meanwhile, Zn2+ ions released from ZIF-8 can inhibit bacterial growth by increasing the permeability of bacterial cell membrane and further strengthen photothermal therapy efficacy by reducing the heat resistance of bacteria. Study showed that bacteria suffered from significant changes in morphology after treatment with ZIF-8-ICG under laser irradiation. The combinational chemo-hyperthermia therapy of ZIF-8-ICG could thoroughly ablate murine subcutaneous abscess induced by methicillin-resistant Staphylococcus aureus (MRSA), exhibiting a nearly 100% bactericidal ratio. Both in vitro and in vivo safety evaluation confirmed that ZIF-8-ICG was low toxic. Overall, our researches demonstrated that ZIF-8-ICG has great potential to be served as an alternative to antibiotics in combating multidrug-resistant bacterial pathogens.


2019 ◽  
Author(s):  
Mohamed. A. Ali ◽  
Jinjun Ren ◽  
Xiaofeng Liu ◽  
Youjie Hua ◽  
Yuanzheng Yue ◽  
...  

<p>Metal-organic framework (MOF) glasses are a newly discovered family of melt-quenched glasses. However, so far it is not known whether these glasses exhibit photonic functionalities. Here, we show the discovery of the luminescent behavior of a MOF glass, i.e., the cobalt doped zeolitic imidazolate frameworks-62 (ZIF-62) glass (Zn<sub>1-<i>x</i></sub> Co<i><sub>x</sub></i> (Im)<sub>1.9</sub> (bIm)<sub>0.1</sub>, <i>x</i> = 0, 0.1 and 0.5), which was obtained by melt-quenching its corresponding ZIF-62 crystal. The synthesized crystal was precipitated in the form of spherical nano/micro-crystalline structure, which collapses structurally to form laminated glass with ultrahigh glass forming ability and the same short range molecular structure of the parent crystalline MOF. We observed the super-broadband mid-infrared (Mid-IR) luminescence (in the wavelength range of 1.5 µm – 4.8 µm) both in the crystalline and amorphous phases. The observed Mid-IR emission originates from d-d transition of Co<sup>2+</sup> ions that is protected by the strong Co-N coordination. The discovery of the luminescent glasses may pave the way towards new photonic applications of bulk MOF glasses, such as Mid-IR lasers. </p>


2021 ◽  
Author(s):  
Louis Frentzel-Beyme ◽  
Pascal Kolodzeiski ◽  
Jan-Benedikt Weiß ◽  
Sebastian Henke

Metal-organic framework (MOF) glasses are a new class of microporous glass materials with immense potential for applications ranging from gas separation to optics and solid electrolytes. Due to the inherent difficulty to determine the atomistic structure of amorphous glasses, the intrinsic structural porosity of MOF glasses is only poorly understood. In this work, the porosity features of a series of prototypical MOF glass formers from the family of zeolitic imidazolate frameworks (ZIFs) and their corresponding glasses is investigated comprehensively. CO2 gas sorption at 195 K allows to follow the evolution of microporosity when transforming from the crystalline to the glassy state of these materials. Based on these data, the pore volume and the real density of the ZIF glasses is quantified for the first time. Additional hydrocarbon sorption data (n-butane, propane and propylene) together with X-ray total scattering experiments prove that the porosity features (in particular the pore size and the pore limiting diameter) of the ZIF glasses depend on the types of organic linkers present in the glass network. This allows formulating first design principles for a targeted tuning of the intrinsic microporosity of MOF glasses. Importantly, these principles are counterintuitive and contrary to established porosity design concepts for crystalline MOFs but show similarities to strategies previously developed for porous polymers.


2019 ◽  
Author(s):  
Malwina Stepniewska ◽  
Kacper Januchta ◽  
Chao Zhou ◽  
Ang Qiao ◽  
Morten M. Smedskjaer ◽  
...  

<p>Metal-organic framework (MOF) glasses is a newly discovered family of melt-quenched glasses. Recently, several intriguing features (e.g., ultrahigh glass forming ability and low liquid fragility) have been discovered in the glasses obtained from zeolitic imidazolate frameworks (ZIFs) that are a subset of MOFs. However, the fracture behavior of ZIF glasses remains elusive. Here, we report on the first important finding, namely, the anomalous crack behavior in a representative ZIF glass, i.e., ZIF-62 glass with the chemical composition of<a> ZnIm<sub>2-<i>x</i></sub>bIm<i><sub>x</sub></i></a>, where the central node – zinc - is coordinated to imidazolate (Im) and benzimidazole (bIm) ligands. By performing micro- and nano-indentation and atomic force microscopy (AFM) analysis, we observe a unique sub-surface cracking phenomenon with induced shear bands on the indent faces, in contrast to the cracking behavior of other types of network glasses. The occurrence of shear bands could be attributed to the breakage of coordinative bonds that are much weaker than ionic and covalent The observed anomalous cracking behavior accords with the high Poisson’s ratio (=0.34) of the ZIF-62 glass. </p>


RSC Advances ◽  
2016 ◽  
Vol 6 (71) ◽  
pp. 67308-67314 ◽  
Author(s):  
Yanjing Yang ◽  
Yang Bai ◽  
Fengqi Zhao ◽  
Ergang Yao ◽  
Jianhua Yi ◽  
...  

Fe-BTC effectively enhances the thermal decomposition of AP and improves the combustion properties of BAMO–THF propellant with AP as the oxidizer.


2019 ◽  
Author(s):  
Mohamed. A. Ali ◽  
Jinjun Ren ◽  
Xiaofeng Liu ◽  
Youjie Hua ◽  
Yuanzheng Yue ◽  
...  

<p>Metal-organic framework (MOF) glasses are a newly discovered family of melt-quenched glasses. However, so far it is not known whether these glasses exhibit photonic functionalities. Here, we show the discovery of the luminescent behavior of a MOF glass, i.e., the cobalt doped zeolitic imidazolate frameworks-62 (ZIF-62) glass (Zn<sub>1-<i>x</i></sub> Co<i><sub>x</sub></i> (Im)<sub>1.9</sub> (bIm)<sub>0.1</sub>, <i>x</i> = 0, 0.1 and 0.5), which was obtained by melt-quenching its corresponding ZIF-62 crystal. The synthesized crystal was precipitated in the form of spherical nano/micro-crystalline structure, which collapses structurally to form laminated glass with ultrahigh glass forming ability and the same short range molecular structure of the parent crystalline MOF. We observed the super-broadband mid-infrared (Mid-IR) luminescence (in the wavelength range of 1.5 µm – 4.8 µm) both in the crystalline and amorphous phases. The observed Mid-IR emission originates from d-d transition of Co<sup>2+</sup> ions that is protected by the strong Co-N coordination. The discovery of the luminescent glasses may pave the way towards new photonic applications of bulk MOF glasses, such as Mid-IR lasers. </p>


2019 ◽  
Author(s):  
Malwina Stepniewska ◽  
Kacper Januchta ◽  
Chao Zhou ◽  
Ang Qiao ◽  
Morten M. Smedskjaer ◽  
...  

<p>Metal-organic framework (MOF) glasses is a newly discovered family of melt-quenched glasses. Recently, several intriguing features (e.g., ultrahigh glass forming ability and low liquid fragility) have been discovered in the glasses obtained from zeolitic imidazolate frameworks (ZIFs) that are a subset of MOFs. However, the fracture behavior of ZIF glasses remains elusive. Here, we report on the first important finding, namely, the anomalous crack behavior in a representative ZIF glass, i.e., ZIF-62 glass with the chemical composition of<a> ZnIm<sub>2-<i>x</i></sub>bIm<i><sub>x</sub></i></a>, where the central node – zinc - is coordinated to imidazolate (Im) and benzimidazole (bIm) ligands. By performing micro- and nano-indentation and atomic force microscopy (AFM) analysis, we observe a unique sub-surface cracking phenomenon with induced shear bands on the indent faces, in contrast to the cracking behavior of other types of network glasses. The occurrence of shear bands could be attributed to the breakage of coordinative bonds that are much weaker than ionic and covalent The observed anomalous cracking behavior accords with the high Poisson’s ratio (=0.34) of the ZIF-62 glass. </p>


Biosensors ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 1
Author(s):  
Jina Ding ◽  
Dongwei Zhang ◽  
Yang Liu ◽  
Xuejia Zhan ◽  
Yitong Lu ◽  
...  

A new double-shelled carbon nanocages material was synthesized and developed an aptasensor for determining Pb2+ in aqueous solution. Herein, nanoporous carbon materials derived from core–shell zeolitic imidazolate frameworks (ZIFs) demonstrated excellent electrochemical activity, stability, and high specificity surface area, consequently resulting in the strong binding with aptamers. The aptamer strands would be induced to form G-quadruplex structure when Pb2+ was introduced. Under optimal conditions, the aptasensor exhibited a good linear relationship of Pb2+ concentration ranging from 0.1 to 10 μg L−1 with the detection limits of 0.096 μg L−1. The feasibility was proved by detecting Pb2+ in spiked water samples and polluted soil digestion solution. The proposed aptasensor showed excellent selectivity and reproducibility, indicating promising applications in environmental monitoring.


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