NANOTECHNOLOGY
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2020
·Vol. 31
·期 19
·194001
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IF 3.551
Bo Wang,Xin Huang,Xiao-Nan Zhou,Qiang Zhi,Liu-Cheng Hao,Zi-Xuan Li,Shan Zhao,Bao-Qiang Hou,Jian-Feng Yang,Kozo Ishizaki
One-dimensional Si3N4 nanostructures are desirable for constructing nanoscale electric and optoelectronic devices due to their peculiar morphologies. Herein, a facile and environmentally friendly catalyst-free method is proposed to synthesize ultra-long single crystal α-Si3N4 nanobelts via carbothermal nitridation of carbon nanotubes at 1750 °C. The obtained α-Si3N4 nanobelts with a flat surface (thickness of ∼150 nm, length of several millimeters) exhibited an extremely high aspect ratio, perfect crystal structure, and high specific surface area of 7.34–10.09 m2 g−1. In addition, the width was increased from approximately 80 nm to 8 μm by increasing the holding time from 1 to 3 h. The nanobelt formation was governed by the vapor–solid (VS) reaction between SiO vapor, N2 and carbon nanotubes, and the vapor–vapor reaction between SiO, CO and N2. The former was responsible for the initial nucleation and successive base-growth of α-Si3N4 nanotubes. The latter additionally contributed to the nanorod and subsequent proto-nanobelt formation and to the growth of the nanobelts. During high-temperature annealing at 1750 °C, the original Si3N4 nanotubes gradually transformed into nanorods, and, finally, nanobelts with stable shapes as a result of surface energy minimization.
研究领域:
材料科学
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纳米技术
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产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Shijiao Zhao,Jing Song,Rui Xu,Lei Nie,Jingtao Ma,Changsheng Deng,Xing Cheng,Xingyu Zhao,Shaochang Hao,Jianjun Li
In this study, zirconium nitride nanopowders with a high specific surface area were synthesized by carbothermal nitridation with fructose as a double-function additive. The precursor was prepared by an internal gelation process. The first function of fructose was to act as an organic carbon source for the nitridation reaction to decrease the apparent activation energy . The second function of fructose was to act as a microstructural controller of products to obtain a high specific surface area of 315.7 m 2 /g. The effects of temperature on the phase composition, chemical elements, morphology and specific surface area were investigated. The microstructure development upon heating was illustrated and the relationship between the structure evolution and variation in the specific surface area was elucidated. This method with fructose as a water-soluble organic additive could be expanded to prepare transition metal nitrides with a high specific surface area.
研究领域:
材料科学
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纳米技术
✓ 已验证
DOI
高影响因子
Scientific Reports
·
2019
·Vol. 9
·期 1
·1-9
·
IF 4.011
Zhao Shijiao,Ma Jingtao,Xu Rui,Lin Xuping,Cheng Xing,Hao Shaochang,Zhao Xingyu,Deng Changsheng,Liu Bing
Zirconium compounds has been widely attention over the last decades due to its excellent physical and chemical properties. Zirconium nitride nanopowders were synthesized via a simple direct carbothermic nitridation process of internal gel derived zirconia in the presence of nano-sized carbon black. The effects of reaction temperature, dwell time and molar ratio of carbon black to Zr (C/Zr) on the phase composition, grain size and crystal parameters of products were studied. Based upon the analysis of crystallite phase evolution and microstructure characterization, it was found that zirconium oxynitride is intermediate product and then O atoms in oxynitride were extracted by oxygen getter, carbon black. Anion sites were directly replaced by N atoms to form rock-salt type nitride in carbothermic nitridation process.
研究领域:
材料科学
·
化学工程
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产品关联
DOI
PubMed
高影响因子
Sustainable Energy & Fuels
·
2020
·Vol. 4
·期 4
·1674-1680
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IF 5.503
Yingchen Yang,Zirui Lou,Weisheng Lei,Yichen Wang,Rong Liang,Chao Qin,Liping Zhu
Perovskite SrNbO2N particles were directly synthesized using a one-step thermal nitridation method with chloride flux and subsequently annealed under an inert Ar flow. By suitable adjustment of the flux synthesis parameters, including the nitridation temperature and the composition of the molten salt, preferable experimental conditions were found to suppress the formation of surface Nb defects and obtain samples with high crystallinity. The different SrNbO2N photoanodes were fabricated using the electrophoretic deposition (EPD) method followed by necking treatment. The SrNbO2N photoanode prepared using the optimum experimental conditions (nitridation temperature: 850 °C, a molar ratio of flux SrCl2 : KCl = 2 : 1) exhibited the highest photocurrent density of 2.0 mA cm−2 at 1.23 VRHE under simulated sunlight (AM 1.5G 100 mW cm−2) in a 1 M NaOH electrolyte. In comparison, the other highly defective SrNbO2N photoanodes demonstrated an unsatisfactory water oxidation performance, which demonstrates the necessity to reduce the destructive effect of defects in order to achieve a higher photocurrent density.
研究领域:
材料科学
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光电化学
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能源材料
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表面科学
✓ 已验证
DOI
高影响因子
COMPOSITES COMMUNICATIONS
·
2020
·
IF 4.915
Zhiyang Jiang,Haoxu Si,Xin Chen,Huimin Liu,Lei Zhang,Yahong Zhang,Chunhong Gong,Jingwei Zhang
In this work, to meet the comprehensive demands for efficiency and lightweight electromagnetic wave absorption (EWA) material, boron nitride/reduced graphene oxide (BN/RGO) nanocomposites were prepared via a one-step thermal nitridation process. The insulative BN component in the obtained nano BN/RGO hybrids realized the regulation of conductivity and thus impedance matching, and the large interface area of the hybrids facilitated the high-frequency polarization effect and contributed to the enhanced EWA performance. Remarkably, the EWA performance of optimized BN/RGO hybrids reached a strong reflection loss ( RL ) of −48.9 dB in a broad effective absorption bandwidth of 4.2 GHz with a low filler content of 3.0 wt. % and at a thin thickness of 2.6 mm, which well outperforms that of most other reported dielectric absorption materials. Our results may light a new way on introducing light element component to produce high-efficiency RGO-based EWA materials with facile and low-cost production process.
研究领域:
材料科学
·
电磁学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）