High Voltage
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2022
·Vol. 8
·期 4
·760-771
·
IF 4.967
Haoou Ruan,Qing Xie,Jingxuan Song,Shenghui Wang,Xiaobin Chang,Yuqin Xu,Fangcheng Lü
Organophilic groups of coupling agents can be the key factor for the electrical performance of Boron Nitride (BN)/meta-aramid composite paper. In this article, four types of triethoxy-silane coupling agents with different organophilic groups, including mercapto-propyl (MP), glycidylether-propyl (GP), amino-propyl (AP) and trideca-fluoro-octyl (TFO) were studied. The structural and electrical properties of modified papers were compared, and the molecular simulation was conducted to reveal the interface interaction of modified BN and aramid. The results show that AP, GP and MP follow the same mechanism, improving the electrical performance by modifying the interface stability and paper structure, and the ranks of improving effects are AP, MP and GP. While, TFO mainly relies on the fluorine components to implement the electrical reinforcement, which compensates for the shortcoming in the paper structure. By choosing TFO and filler content of 15 wt%, the optimal breakdown strength of the paper can be increased to 28.17 kV/mm, 1.8 times that of the paper doped with the hydroxylated BN.
研究领域:
材料科学
·
电气工程
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DOI
高影响因子
Frontiers in Energy Research
·
2023
·
IF 3.4
Jia Pingshan,Sun Jing,Wang Wenlong,Song Zhanlong,Zhao Xiqiang,Mao Yanpeng
Microwave-induced metal arc discharge provides an intriguing solution for the synthesis of carbon-coated metal nanoparticles (M@CNPs) due to its fast formation and improved quality of products, however, the underpinning reaction mechanism is not comprehensively revealed. In this work, the effect of arc discharge intensity on the product morphology is firstly investigated by adjusting microwave power. And then, the effects of the organic groups (i.e. cyclopentadienyl v. s Acetylacetonate groups) and metal catalysis on the product morphology are also investigated by selecting ferrocene, iron acetylacetonate, nickelocene, and nickel acetylacetonate as precursors. Specifically, moderate microwave power can not only destroy the precursor to form carbon nanosheets by inducing intense discharge heat release but also provide sufficient intermittency to allow the carbon nanosheets to deposit on the surface of the metal core, which is an important precondition in fabricating M@CNPs. The structure of organic groups in the precursor also plays a predominant role in adjusting product morphology. Cyclopentadienyl groups tend to encapsulate the metal core to form graphitized carbon shells as the coordination bond between cyclopentadienyl and metal is recognized as a very strong covalent bond that confines the cyclopentadienyl collapse to metal core, and the cyclic structure facilitates the formation of graphite. In contrast, the acetylacetonate groups intend to combine randomly due to their open-loop structure. Moreover, for open-loop structures such as acetylacetonate groups, metal catalysis also affects the growth trend, of which Ni is more likely to induce the formation of carbon nanotubes relative to Fe. This work can provide a good reference for the synthesis of M@CNPs with controllable morphology.
研究领域:
材料科学
·
化学
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产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Yan Liang,Huacheng Zhang,Jin Zhang,Xuan Cheng,Yinlong Zhu,Laiming Luo,Shanfu Lu,Jing Wei,Huanting Wang
The synthesis of two-dimensional (2D) porous carbon materials has attracted much attention due to their widespread applications. In this work, Fe/N doped hierarchical porous carbon nanosheets are developed through thermal activation step based on organic groups triggered polymer particles exfoliation. Polymer nanoparticles are exfoliated by the reaction between the phenolic hydroxyl groups and the amino groups. The gas produced from dicyandiamide then blows polymer fragments into ultrathin flexible carbon nanosheets under pyrolysis process , along with nitrogen doping. The Fe–N–C catalyst exhibits half-wave potential (E 1/2 ) at 0.852 V (vs. RHE) in 0.1 M KOH and at 0.686 V (vs. RHE) in 0.5 M H 2 SO 4 for oxygen reduction reaction . Additionally, the polymer electrolyte membrane fuel cell that employs the catalyst at the cathode exhibits good durability without showing significant degradation after 96 h continuous operation. Furthermore, this method can be generalized to synthesize carbon nanosheets by using various polymer precursors. This work provides a new and general strategy for preparing porous carbon or metal/carbon nanosheets, which paves the way for the mass production of effective 2D carbon materials in many important applications.
研究领域:
材料科学
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化学工程
·
能源科学
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2015
·Vol. 40
·期 1
·825-831
·
IF 3.086
Zhenhui Liu,Lianxi Chen,Xinshan Ye,Huogen Yu,Jie Li,Fanlong Zeng
Hollow mesoporous silica nanospheres with high-density functional groups were successfully prepared based on an effective basic selective etching strategy. In this work, thiol-functionalized hollow mesoporous silica nanospheres were synthesized by the etching of cyano-SiO2@thiol-SiO2 and vinyl-SiO2@thiol-SiO2 core–shell composite particles. The composite particles were fabricated, respectively, via a two-step sol–gel reaction of different organosilanes. The different alkali resistance between the inner core and the outer shell of the composite particles is the key to fabricating hollow silica nanospheres in this paper. When the core–shell composite particles were treated with Na2CO3 and NaOH, the thiol functionalized outer shell showed higher stability than the cyano and vinyl functionalized inner core. The inner core, which is less stable under alkaline conditions, will be etched off in base, resulting in a hollow structure. Transmission electron microscopy (TEM) results demonstrate that large-scale hollow mesoporous silica nanospheres can be obtained through this method. In addition, it is also found that the morphology of samples may be regularly changed by manipulating the concentration of alkali in the etching process. Fourier transform infrared (FT-IR) and energy dispersive spectrometry (EDS) confirm that the thiol groups exist in the organic functionalized hollow mesoporous silica nanospheres obtained. We expect that this facile strategy can be extended to fabricate organic functionalized hollow mesoporous silica nanospheres with more other valuable functional groups.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Xiang Li,Wei Liu,Yan Wang,Linze Lv,Huaiwei Feng,Weibo Huang,Yu Sun,Weixing Xiong,Honghe Zheng
Covalent organic frameworks (COFs) have been widely used in various fields due to their abundant elemental resources, easy structure control, and abundant tunable porous structures. COFs containing electroactive organic groups with reversible redox behavior are potential electrode materials for next-generation high-performance lithium-ion batteries (LIBs). However, the aromatic conjugated structure of the backbone moiety in most reported COFs cannot participate in redox reactions, resulting in low capacity of COFs. At the same time, the synthesis processes of COFs are usually complicated and generally requires high temperature and high pressure. On this basis, an imine bond-rich COF (TAACOF) with reversible Li-ion bonding is developed, which has the advantages of facile preparation and low energy consumption. In particular, the lone pair electrons of the N atom in the imine bond can induce lithium ions to combine with the aromatic conjugated structure, which greatly improves the capacity of the TAACOF electrode. After 800 cycles, the active sites of the TAACOF are fully activated, and after a 14-electron redox reaction, the specific capacity can reach as high as 1035.7 mAh/g.
研究领域:
材料科学
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电化学
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储能
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有机化学
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纳米技术
✓ 已验证
DOI
高影响因子
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