Browsing by Author "Yoshitake, Masuda"

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ELECTRODEPOSITION OF WO3 NANOSTRUCTURED THIN FILMS FOR ELECTROCHROMIC AND H2S GAS SENSOR APPLICATIONS
(Elsevier, 2017-09-30) Poongodi, S; Palaniswamy, Suresh Kumar; Mangalaraj, D; Ponpandian, N; Meena, P; Yoshitake, Masuda; Chongmu, Lee
In this work, Vertically oriented WO3 nanoflakes array films was synthesized via the template free facile electrodeposition method at room temperature. WO3 nanoflakes arrays was adopted as an effective cathode electrode material in the electrochemical devices structure. The WO3 material exhibits superior electrochromic performance shows a larger optical modulation (68.89% at 550 nm), faster response time (tb = 1.93 s, tc = 2.87 s), a higher coloration efficiency of about 154.93 cm2 C−1 and with excellent cyclic stability over 2000 cycles without any degradation. Futhermore, WO3 nanoflakes array film was used for the detection of H2S gas that showed excellent response. A considerable increase in porosity and high surface roughness could be conducive for such an excellent and superior electrochromic characteristic as well as gas sensing performances. These results indicates that fabricated WO3 nanoflakes array film by a simple strategy holds a great promise for potential multifunctional applications such as smart windows, gas sensors and optical sensors.
ENHANCED PHOTOCATALYTIC ACTIVITY OF COBALT-DOPED CEO2 NANORODS (Article)
(Springer Link, 2012-09-28) Sabari Arul, N; Mangalaraj, D; Pao Chi, Chen; Ponpandian, N; Meena, P; Yoshitake, Masuda
In this paper, CeO2 and cobalt-doped CeO2 nanorods synthesized by surfactant free co-precipitation method. The microstructures of the synthesized products were characterized by XRD, FESEM and TEM. The structural properties of the grown nanorods have been investigated using electron diffraction and X-ray diffraction. High resolution transmission electron microscopy studies show the polycrystalline nature of the Co-doped cerium oxide nanorods with a length of about 300 nm and a diameter of about 10 nm were produced. The X-ray Photoelectron spectrum confirms the presence of cobalt in cerium oxide nanorods. From BET, the specific surface area of the CeO2 (Co-doped) nanostructures (131 m2 g−1) is found to be significantly higher than that of pure CeO2 (52 m2 g−1). The Co-doped cerium nanorods exhibit an excellent photocatalytic performance in rapidly degrading azodyes acid orange 7 (AO7) in aqueous solution under UV illumination.
SYNTHESIS OF CEO2 NANORODS WITH IMPROVED PHOTOCATALYTIC ACTIVITY: COMPARISON BETWEEN PRECIPITATION AND HYDROTHERMAL PROCESS (Article)
(Springer Link, 2013) Sabari Arul, N; Mangalaraj, D; Tae Whan, Kim; Pao Chi, Chen; Ponpandian, N; Meena, P; Yoshitake, Masuda
The main purpose of this article is to examine the surface free cerium oxide (CeO2) nanostructures prepared by different methods. CeO2 nanoparticles and nanorods were prepared by two different methods including precipitation and hydrothermal process. In precipitation process the nanoparticles were prepared at room temperature, while in hydrothermal process nanorods were prepared at high temperature. X-ray and electron diffraction analysis show the presence of CeO2. X-ray photoelectron spectroscopy (XPS) confirms the presence of CeO2 in both nanostructures. From BET, the specific surface area of nanorods (110 m2g−1) is found to be higher than nanoparticles (52 m2g−1). Also, the effect of morphology on their photodegradation of azo dye acid orange 7 (AO7) under UV–Visible light has been successfully investigated. The results show that the CeO2 nanorods synthesized by hydrothermal method have high surface area and exhibit improved performance in the photocatalytic activity.
SYNTHESIS OF INDIUM OXIDE CUBIC CRYSTALS BY MODIFIED HYDROTHERMAL ROUTE FOR APPLICATION IN ROOM TEMPERATURE FLEXIBLE ETHANOL SENSORS (Article)
(Elsevier, 2012-03-15) Seetha, M; Meena, P; Mangalaraj, D; Yoshitake, Masuda; Senthil, K
Indium oxide cubic crystals were prepared by using hexamethylenetetramine and indium chloride without the addition of any structure directing agents. The chemical route followed in the present work was a modified hydrothermal synthesis. The average crystallite size of the prepared cubes was found to be 40 nm. A blue emission at 418 nm was observed at room temperature when the sample was excited with a 380 nm Xenon lamp. This emission due to oxygen vacancies made the material suitable for gas sensing applications. The synthesized material was made as a composite film with polyvinyl alcohol which was more flexible than the films prepared on glass substrates. This flexible film was used as a sensing element and tested with ethanol vapours at room temperature. The film showed fast response as well as recovery to ethanol vapours with a sensor response of about 1.4 for 100 ppm of the gas.