Zeolite Imidazolate Frameworks-67 Precursor to Fabricate a Highly Active Cobalt-Embedded N-Doped Porous Graphitized Carbon Catalyst for the Thermal Decomposition of Ammonium Perchlorate.
24 Sep 2021-Vol. 6, Iss: 39, pp 25440-25446
TL;DR: In this paper, a well-designed cobalt-embedded N-doped porous graphitized carbon (Co@NC) catalyst is obtained by high-temperature calcination of a zeolite imidazolate frameworks-67 precursor, in which the cobalt catalytic active center realizes effective nanoscale dispersion.
Abstract: The more apparent specific heat release at a lower high-temperature decomposition (HTD) temperature of ammonium perchlorate (AP) poses a challenge for the development of highly active catalysts. In this work, a well-designed cobalt-embedded N-doped porous graphitized carbon (Co@NC) catalyst is obtained by high-temperature calcination of a zeolite imidazolate frameworks-67 precursor, in which the cobalt catalytic active center realizes effective nanoscale dispersion; meanwhile, the cobalt and N-doped porous graphitized carbon can release considerable heat after oxidation, and the cobalt oxides have an excellent catalytic effect on reducing the HTD temperature of AP. The catalytic activity of Co@NC was tested by a differential thermal analytical method. The results indicated that the HTD peak of AP was significantly decreased by 100.5 °C, the apparent activation energy of the HTD reaction of AP was reduced by 82.0 kJ mol-1, and the heat release compared with pure AP increased 2.9 times. On teh basis of these findings, Co@NC is expected to be one of the best candidate materials for AP thermal decomposition.
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TL;DR: DC@ZIF8-MEMC exhibited outstanding photothermal conversion properties and excellent antitumor effect in vitro and in vivo, and the hypoxia relief by CAT was proved to have good sensitization effect on chemo-photothermal combined therapy.
Abstract: Tumor hypoxic microenvironment can reduce the therapeutic effects of chemotherapy, radiotherapy, photodynamic therapy, immunotherapy, etc. It is also a potential source of tumor recurrence and metastasis. A biomimetic nanosystem based on zeolitic imidazolate framework 8 (ZIF8), which had multifunctions of hypoxia relief, chemotherapy, and photothermal therapy, was established to improve tumor hypoxic microenvironment and overcome the corresponding therapeutic resistance. ZIF8 enveloped with DOX and CuS nanoparticles (DC@ZIF8) was synthesized by a sedimentation method. Red blood cell membrane and catalase (CAT) were coated onto DC@ZIF8 and biomimetic nanosystem (DC@ZIF8-MEMC) was formed. The designed DC@ZIF8-MEMC had a shape of polyhedron with an average particle size around 254 nm. The loading content of DOX, CAT, and CuS was 4.9%, 6.2%, and 2.5%, separately. The release of DOX from DC@ZIF8-MEMC was pH dependent and significantly faster at pH 5 due to the degradation of ZIF8. DC@ZIF8-MEMC exhibited outstanding photothermal conversion properties and excellent antitumor effect in vitro and in vivo. Moreover, the hypoxia relief by CAT was proved to have good sensitization effect on chemo-photothermal combined therapy. DC@ZIF8-MEMC is a prospective nanosystem, which can realize great chemo-photothermal synergistic antitumor effect under the sensitization of CAT. The biomimetic multifunctional nanoplatform provides a potential strategy of chemo-photothermal synergistic antitumor effect under the sensitization of CAT.
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TL;DR: The ammonium perchlorate (AP) as an oxidizer is widely employed in composite solid propellants (CSPs) and the thermal decomposition kinetics of AP can significantly affect the combustion behavior of CSPs as discussed by the authors .
Abstract: The ammonium perchlorate (AP) as an oxidizer is widely employed in composite solid propellants (CSPs), and the thermal decomposition kinetics of AP can significantly affect the combustion behavior of CSPs....
TL;DR: In this paper , six ferrocenyl glycidyl ethers were designed and synthesized to improve the anti-migration properties, and the related spectra characterization techniques were adopted to confirm their molecular structures.
References
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7,498 citations
TL;DR: Electrochemical data strongly demonstrate that this nanoporous hybrid carbon material integrates the advantageous properties of the individual NC and GC, exhibiting a distinguished specific capacitance calculated from the galvanostatic charge-discharge curves at a current density of 2 A·g(-1).
Abstract: Core–shell structured ZIF-8@ZIF-67 crystals are well-designed and prepared through a seed-mediated growth method. After thermal treatment of ZIF-8@ZIF-67 crystals, we obtain selectively functionalized nanoporous hybrid carbon materials consisting of nitrogen-doped carbon (NC) as the cores and highly graphitic carbon (GC) as the shells. This is the first example of the integration of NC and GC in one particle at the nanometer level. Electrochemical data strongly demonstrate that this nanoporous hybrid carbon material integrates the advantageous properties of the individual NC and GC, exhibiting a distinguished specific capacitance (270 F·g–1) calculated from the galvanostatic charge–discharge curves at a current density of 2 A·g–1. Our study not only bridges diverse carbon-based materials with infinite metal–organic frameworks but also opens a new avenue for artificially designed nanoarchitectures with target functionalities.
1,233 citations
TL;DR: This work adopts metal-organic frameworks (MOFs) to assist the preparation of a catalyst containing single Ni sites for efficient electroreduction of CO2 and presents some guidelines for the rational design and accurate modulation of nanostructured catalysts at the atomic scale.
Abstract: Single-atom catalysts often exhibit unexpected catalytic activity for many important chemical reactions because of their unique electronic and geometric structures with respect to their bulk counterparts. Herein we adopt metal–organic frameworks (MOFs) to assist the preparation of a catalyst containing single Ni sites for efficient electroreduction of CO2. The synthesis is based on ionic exchange between Zn nodes and adsorbed Ni ions within the cavities of the MOF. This single-atom catalyst exhibited an excellent turnover frequency for electroreduction of CO2 (5273 h–1), with a Faradaic efficiency for CO production of over 71.9% and a current density of 10.48 mA cm–2 at an overpotential of 0.89 V. Our findings present some guidelines for the rational design and accurate modulation of nanostructured catalysts at the atomic scale.
1,005 citations
TL;DR: In this article, the authors provide a sketch about the critical roles of single-atom catalysts and some key issues that have to be contended while considering their energy applications, and some foresighted ideas and predictions on the future directions of MOF-based SACs are pointed out.
496 citations
TL;DR: In this article, a novel Zn/Co zeolitic imidazolate framework (ZIF) has been constructed by an easy and straightforward room temperature technique Several characterization techniques such as SEM, TEM-EDX, single-crystal XRD and ICP have been applied to confirm that the structure formed is a sodalite (SOD) cage type structure.
Abstract: A novel Zn/Co zeolitic imidazolate framework (ZIF) has been constructed by an easy and straightforward room temperature technique Several characterization techniques such as SEM, TEM-EDX, single-crystal XRD and ICP have been applied to confirm that the structure formed is a sodalite (SOD) cage type structure The Zn/Co-ZIF possesses a high nano-crystallinity and porosity with a large surface area By tuning the amount of Co and Zn in the Zn/Co zeolitic imidazolate framework, the physical and chemical properties have been improved compared with those of the single metal frameworks (ZIF-8 and ZIF-67) Consequently, the Zn/Co-ZIF was investigated for two different applications; gas adsorption (CO2, CH4 and N2) and catalysis (CO2 conversion to cyclic carbonates) and the obtained results were compared with the performance of previously reported single metal frameworks (ZIF-8 and ZIF-67) Additionally, hydrolytic stability tests under ambient conditions and immersed in water at 75 °C were performed and pointed out that Zn/Co-ZIF exhibits a higher stability Moreover, based on these results, the Zn/Co-ZIF demonstrates better properties compared with ZIF-8 and ZIF-67
453 citations