Reactivity adjustment from the contact extent between CuO and Al phases in nanothermites

Chen, Yajie; Ren, Wei; Zheng, Zilong; Wu, Ganggang; Hu, Bin; Chen, Junhong; Wang, Jiaxin; Yu, Chunpei; Ma, Kefeng; Zhou, Xinli; Zhang, Wenchao

doi:10.1016/j.cej.2020.126288

Cited by 35 publications

(20 citation statements)

References 37 publications

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“…Much research in nanothermites have focused on the Al/CuO systems due to their high energy density 4,5 , and because they allow fabricating thermite systems with varying shapes/geometries, i.e. multilayered 6,7 , core/shell 8,9 , 3D assembled particles 10,11 , and 3D porous nanostructures 12 . It has been observed that the formulation and deposition method greatly affect the energy transfer mechanisms and combustion behavior, which depend on several factors, such as reactant intimacy, material confinement or gas generation.…”

Section: Introductionmentioning

confidence: 99%

Engineered Porosity-Induced Burn Rate Enhancement in Dense Al/CuO Nanothermites

Julien

Wang

et al. 2022

ACS Appl. Energy Mater.

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This work investigates the combustion of porous Al/CuO thermites, i.e. nanolaminates fabricated with various densities of micron sized air-filled pores in the range of 0 -20 vol%.High-speed videography and pyrometry of the high-temperature propagating flame were used to analyze the effect of porosity on propagation velocity. Incorporating micron sized pores in Al/CuO nanolaminates results in a faster burn rate (burn rate enhancement of 18% for pores loading of 20 vol%) while the flame temperature remains the same. Microscopic observations of the flame front in porous nanolaminates show hot-spots around each pore in the upstream of the flame but no advection. Conduction remains the dominant heat transfer mechanism in dense thermite configuration (80 % TMD) and the causes of burn rate enhancement when pores are embedded into the nanolaminate are found to be the convection of the trapped air inside the pores upon heating together with a possible modification of the reaction chemistry leading to a lowering of the ignition threshold of thermite around each micron sized pores. Indeed, this hot gaseous O2 species trapped into the pores diffuse and react with solid Al on the inner wall of the pores to form Al2O3. This This gas phase mediated reaction mechanism in the pores occurs at a lower temperature than the diffusion-based mechanism of the aluminum cations and oxide anions across the alumina shell as in fully dense Al/CuO nanolaminates. The critical size of the pores beyond which their beneficial effect disappears is difficult to estimate, but, this study showed that 100 × 100 µm² pores has almost no effect on the combustion with an average burn rate increase of only ~4% compare to fully dense nanolaminate part.

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Section: Introductionmentioning

confidence: 99%

Engineered Porosity-Induced Burn Rate Enhancement in Dense Al/CuO Nanothermites

Julien

Wang

et al. 2022

ACS Appl. Energy Mater.

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“…48-1548) within 6 days (Figure S2b), which was verified by X-ray diffraction (XRD) (Figure S2c). Interestingly, the transferrin loaded on the CP NPs can obviously enhance the stability of CP NPs, and the CP@Tf NPs are very stable for at least a month (Figure S2d). It has been reported that some protein-coated nanomaterials can avoid the environmental impact because of the protein protective layer .…”

Section: Resultsmentioning

confidence: 99%

A Copper Peroxide Fenton Nanoagent-Hydrogel as an In Situ pH-Responsive Wound Dressing for Effectively Trapping and Eliminating Bacteria

Wang

Yao

et al. 2022

ACS Appl. Bio Mater.

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Bacterial infection has been a great threat to wounds due to the abuse of antibiotics and drug resistance. Elaborately constructing an efficient antibacterial strategy for accelerated healing of bacteria-infected wounds is of great importance. Herein, we develop a transferrin-conjugated copper peroxide nanoparticlehydrogel (denoted as CP@Tf-hy) wound dressing with no toxicity to mammalian cells at a test dosage. When exposed to an initial acidic wound environment, the CP@Tf-hy simultaneously displays in situ self-supplied H 2 O 2 and pH-responsive release of Fenton catalytic copper ions accompanied by highly toxic hydroxyl radical (•OH) generation against antibiotic-resistant bacteria. Meanwhile, the positively charged CP@Tf-hy can efficiently trap and restrain negatively charged bacteria to the range of •OH destruction to greatly overcome its intrinsic disadvantages of short life and diffusion distance. Importantly, the CP@Tf-hy consumes the bacterial overexpressed antioxidant glutathione while boosting Fenton catalytic copper(I) ions to generate more •OH. The synergistic effects of the enhanced Fenton reaction, responsive copper ion release, and bacterial trapping can achieve high bacterial elimination efficacy (7 log reduction). In vivo investigations demonstrate that the porous CP@Tf-hy significantly promotes hemostasis, cell proliferation, and migration of the wound, consequently accelerating bacteria-infected wound healing. The safe, low-cost, and all-in-one CP@Tf-hy holds great prospects as an antibacterial dressing for rapid resistant bacteria-infected purulent wound healing.

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“…A thermal reaction is a typical solid-state reaction having highly exothermic and self-propagating characteristics [ 13 ]. The interfacial diffusion generally determines the heat and mass transfer, which is a fundamental process affecting combustion efficiency and energy release [ 14 ]. In nanothermites, oxidizers and fuel contact each other at the nanoscale, the intimacy between oxidizers and fuel reduces, which in turn causes an extraordinary burning rate and an outstanding efficiency of energy release.…”

Section: Introductionmentioning

confidence: 99%

“…Due to the ease with which energetic nanothermites aggregate, it is difficult to considerably improve or accurately manage their performance. In this context, a variety of attempts such as the sol–gel method [ 15 ], electrophoretic deposition [ 16 ], electrostatic assembly [ 17 ], and magnetron sputtering [ 14 ] have been made to explore the strategies to prepare nanothermites. Although the methods described above can be implemented simply in a variety of domains, they are not suited for large-scale applications.…”

Section: Introductionmentioning

confidence: 99%

Peptide Assembly of Al/CuO Nanothermite for Enhanced Reactivity of Nanoaluminum Particles

Jin

Song²,

Liu³

et al. 2022

IJMS

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Biological self-assembly procedures, which are generally carried out in an aqueous solution, have been found to be the most promising method for directing the fabrication of diverse nanothermites, including Al/CuO nanothermite. However, the aqueous environment in which Al nanoparticles self-assemble has an impact on their stability. We show that using a peptide to self-assemble Al or CuO nanoparticles considerably improves their durability in phosphate buffer aqueous solution, with Al and CuO nanoparticles remaining intact in aqueous solution for over 2 weeks with minimal changes in the structure. When peptide-assembled Al/CuO nanothermite was compared with a physically mixed sample in phosphate buffer for 30 min, the energy release of the former was higher by 26%. Furthermore, the energy release of peptide-assembled Al/CuO nanocomposite in phosphate buffer showed a 6% reduction by Day 7, while that of the peptide-assembled Al/CuO nanocomposite in ultrapure water was reduced by 75%. Taken together, our study provides an easy method for keeping the thermal activity of Al/CuO nanothermite assembled in aqueous solution.

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Reactivity adjustment from the contact extent between CuO and Al phases in nanothermites

Cited by 35 publications

References 37 publications

Engineered Porosity-Induced Burn Rate Enhancement in Dense Al/CuO Nanothermites

Engineered Porosity-Induced Burn Rate Enhancement in Dense Al/CuO Nanothermites

A Copper Peroxide Fenton Nanoagent-Hydrogel as an In Situ pH-Responsive Wound Dressing for Effectively Trapping and Eliminating Bacteria

Peptide Assembly of Al/CuO Nanothermite for Enhanced Reactivity of Nanoaluminum Particles

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