Ag@SnO2 core–shell material for use in fast-response ethanol sensor at room operating temperature

2013 ◽  
Vol 178 ◽  
pp. 185-191 ◽  
Author(s):  
Ren-Jang Wu ◽  
Da-Jun Lin ◽  
Ming-Ru Yu ◽  
Ming Hun Chen ◽  
Hsiao-Fang Lai
2015 ◽  
Vol 13 (10) ◽  
pp. 872-877 ◽  
Author(s):  
Bin Jiang ◽  
Yong Zhang ◽  
Xuejun Zheng ◽  
Peiwen Li ◽  
Mengjiao Yuan ◽  
...  

2013 ◽  
Vol 734-737 ◽  
pp. 2191-2194
Author(s):  
Li Li Wu ◽  
Yuan Lian ◽  
Dan Liu ◽  
Hua Zheng ◽  
Dian Wu Huang

In this study, flame retardant microcapsules were synthesized using magnesium hydroxide as core materials, melamine resin as the shell material. The structure, diameters and thermal properties of prepared microcapsules were investigated by using FTIR, ELS, DSC and TGA. The effects of core/shell ratio on the properties of microcapsules were studied.Flame retardant materials of low-density polyethylene/magnesium hydroxide microcapsules were prepared.The tensile strength and elongation at break tests were performed to determine its mechanical property.Inflammability of the materials was also studied.The results showed the prepared magnesium hydroxide microcapsule shows good thermal stability and it has free compatibility with the polymer.The composites of HDPE/MH microcapsules have good performance.


2005 ◽  
Vol 486-487 ◽  
pp. 485-488 ◽  
Author(s):  
Hong Quang Nguyen ◽  
Mai Van Trinh ◽  
Jeung Soo Huh

The effect of operating temperature on characteristics of single-walled carbon nanotubes (SWNT) based gas sensor was investigated. SWNT-based sensor was fabricated from SWNT powder (Iljin Nanotech, Korea) by screen-printing method. SWNT powder (30 mg, AP grade) was dispersed into 0.78 gram a-terpineol (Aldrich) by ultrasonic vibration for 1 hour then stirred manually for 1 hour to increase adhesion. From this condensed solution, a thick film of SWNT was printed onto alumina substrates. The film then was sintered at 300oC for 2 hours to remove residual impurities. Upon exposure to some gases such as nitrogen, ammonia or nitric oxide, resistance of the sensor dramatically changes due to gas adsorption. In our experiments, SWNT-based sensor was employed to detect NH3 gas in N2 ambience. After saturated of N2, the sensor exposes to NH3 with various concentrations (from 5 ppm to 100 ppm, diluted by N2 as carrier gas). This sensor exhibits a fast response, high sensitivity but slow recovery at room temperature. By heating at high temperature and increasing the flow-rate of carrier gas, NH3 gas desorbs easily and recovery of the sensor improved. The heating also influenced the characteristics of sensors such as response and reproducibility. Other special changes in electric property of SWNT-based sensor caused by heating are also discussed.


Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2084 ◽  
Author(s):  
Xiuru Xu ◽  
Wei Wang ◽  
Bolun Sun ◽  
Xue Zhang ◽  
Rui Zhao ◽  
...  

In this work poly(3,4-ethylenedioxythiophene) (PEDOT) coated SnO2-Fe2O3 continuous nanotubes with a uniform core–shell structure have been demonstrated for rapid sensitive detection of iodide ions. The SnO2-Fe2O3 nanotubes were firstly fabricated via an electrospinning technique and following calcination process. An in situ polymerization approach was then performed to coat a uniform PEDOT shell on the surface of as-prepared SnO2-Fe2O3 nanotubes by vapor phase polymerization, using Fe2O3 on the surface of nanotubes as an oxidant in an acidic condition. The resultant PEDOT@SnO2-Fe2O3 core-shell nanotubes exhibit a fast response time (~4 s) toward iodide ion detection and a linear current response ranging from 10 to 100 μM, with a detection limit of 1.5 μM and sensitivity of 70 μA/mM/cm2. The facile fabrication process and high sensing performance of this study can promote a wide range of potential applications in human health monitoring and biosensing systems.


2018 ◽  
Vol 33 (3) ◽  
pp. 589-597 ◽  
Author(s):  
Millicent Appiah ◽  
Hua Hao ◽  
Wenjin Chen ◽  
Cheng Chen ◽  
Zhonghua Yao ◽  
...  

2007 ◽  
Vol 60 (7) ◽  
pp. 457 ◽  
Author(s):  
Joel van Embden ◽  
Jacek Jasieniak ◽  
Daniel E. Gómez ◽  
Paul Mulvaney ◽  
Michael Giersig

Passivation of CdSe semiconductor nanocrystals can be achieved by overcoating the particles with a homogeneous shell of a second semiconductor. Shell layers are grown in monolayer steps to ensure homogeneous growth of the shell. The relative band edges of the two materials determine the photoreactiveity of the resultant core-shell nanocrystals. The critical role of ligands in minimizing nucleation of the shell material during the growth of the passivating layer is emphasized. The delocalization of charge carriers into the shell layers can be followed spectroscopically during the growth processes. The relative spectral shifts are directly correlated to the relative energies of the band edges.


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