Ottawa Hills High School

Toledo, OH, United States

Ottawa Hills High School

Toledo, OH, United States
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Gan Y.X.,University of Toledo | Zeng X.,University of Toledo | Su L.,University of Toledo | Yang L.,University of Toledo | And 2 more authors.
Materials Research Bulletin | Year: 2011

In this paper, multilayer oxide nanorods were deposited in the nanopores of anodic aluminum oxide (AAO) via solution infiltration followed by heat treatment. The nanorods have a core-shell structure. First, the shell (nanotube) with the thickness of about 40 nm was made of TiO2 through the hydrolysis of (NH4)2TiF6. Second, silver nanoparticles with the diameter of about 3 nm were added into the TiO 2 layer through thermal decomposition of AgNO3 at elevated temperatures. Then, cylindrical cores (nanorods) of CoO and ZnO with 200 nm diameter were prepared, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and composition of the nanorods. UV-vis light absorption measurements in the wavelength range from 350 to 1000 nm were performed to study the effect of nanorod and nanoparticle addition on the light absorption property of the alumina nanocomposites. It is found that CoO nanorods increase the light absorption of the alumina matrix composite in the wavelength range from 500 nm to 800 nm, but the TiO2 shell does not increase the light absorption much. The ZnO nanorods do not change the light absorption either. However, the addition of silver nanoparticles significantly enhances light absorption of both AAO/TiO2/Ag/CoO and AAO/TiO2/Ag/ZnO nanocomposites. This increase in the visible light absorption reveals that there exists surface plasmon around the fine silver nanoparticles in the nanorods. © 2011 Elsevier Ltd. All rights reserved.


Gan Y.X.,University of Toledo | Gan B.J.,Ottawa Hills High School | Zhang L.,Brookhaven National Laboratory
Materials Letters | Year: 2011

Iron as a catalyst has wide applications for hydrogen generation from ammonia, photodecomposition of organics, and carbon nanotube growth. Tuning the size and shape of iron is meaningful for improving the catalysis efficiency. It is the objective of this work to prepare nanostructured iron with high surface area via electrochemical deposition. Iron nanoneedles were successfully electrodeposited on Ti supported TiO2 nanotube arrays in a chlorine-based electrolyte containing 0.15 M FeCl2•4H 2O and 2.0 M HCl. Transmission electron microscopic analysis reveals that the average length of the nanoneedles is about 200 nm and the thickness is about 10 nm. It has been found that a high overpotential at the cathode made of Ti/TiO2 nanotube arrays is necessary for the formation of the nanoneedles. Cyclic voltammetry test indicates that the electrodeposition of iron nanoneedles is a concentration-limited process. © 2011 Elsevier B.V. All Rights Reserved.


Gan Y.X.,University of Toledo | Gan B.J.,Ottawa Hills High School | Clark E.,University of Toledo | Su L.,University of Toledo | Zhang L.,Brookhaven National Laboratory
Materials Research Bulletin | Year: 2012

In this work, a novel photoelectrochemical fuel cell consisting of a titanium dioxide nanotube array photosensitive anode and a platinum cathode was made for decomposing environmentally hazardous materials to produce electricity and clean fuel. Titanium dioxide nanotubes (TiO 2 NTs) were prepared via electrochemical oxidation of pure Ti in an ammonium fluoride and glycerol-containing solution. Scanning electron microscopy was used to analyze the morphology of the nanotubes. The average diameter, wall thickness and length of the as-prepared TiO 2 NTs were determined. The photosensitive anode made from the highly ordered TiO 2 NTs has good photo-catalytic property, as proven by the decomposition tests on urea, ammonia, sodium sulfide and automobile engine coolant under ultraviolet (UV) radiation. To improve the efficiency of the fuel cell, doping the TiO 2 NTs with a transition metal oxide, NiO, was performed and the photosensitivity of the doped anode was tested under visible light irradiation. It is found that the NiO-doped anode is sensitive to visible light. Also found is that polyaniline-doped photosensitive anode can harvest photon energy in the visible light spectrum range much more efficiently than the NiO-doped one. It is concluded that the nanostructured photoelectrochemical fuel cell can generate electricity and clean fuel by decomposing hazardous materials under sunlight. © 2012 Elsevier Ltd.


Gan Y.X.,University of Toledo | Shanmugam R.K.,University of Toledo | Gan B.J.,Ottawa Hills High School | Zhang B.,University of Toledo | Su L.,University of Toledo
Journal of Nanotechnology | Year: 2011

To increase the performance of photochemical fuel cells, nonequilibrium electrodeposition has been performed on Cu and Ni to make photosensitive anodes. Processing parameters including electrolyte concentration, and electrode potential were studied using cyclic voltammetry. Scanning electron microscopy (SEM) and X-ray Spectroscopy (EDS) were performed to understand the formation of the nanostructures during the nonequilibrium deposition of copper fractals. An increase in the deposition rate was observed with the increase in electrolyte concentration (from 0.05M to 1.0M). Similar trend was found when the cathode potential was decreased from -0.5V to -4.5V. The effect of substrate material was also examined. Porous fractal structures on copper were achieved, while the deposited material showed high density of surface cracks on nickel. The fractal structures deposited on copper electrode with the increased surface area were converted into copper oxide by oxidation in air. Such oxide samples were made into anodes for photochemical fuel cell application. We demonstrated that an increase in the magnitude of open circuit output voltage is associated with the increase in the fractal surface area under the ultraviolet irradiation test conditions. However, the electrodeposited fractals on nickel showed very limited increase in the magnitude of open circuit voltage. © 2011 Rajesh K. Shanmugam et al.


Gan Y.X.,University of Toledo | Gan B.J.,Ottawa Hills High School | Su L.,University of Toledo
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2011

We made a biophotofuel cell consisting of a titanium dioxide nanotube array photosensitive anode for biomass decomposition, and a low-hydrogen overpotential metal, Pt, as the cathode for hydrogen production. The titanium dioxide nanotubes (TiO2 NTs) were prepared via electrochemical oxidation of pure Ti in NaF solutions. Scanning electron microscopy was used to analyze the morphology of the nanotubes. The average diameter, wall thickness and length of the as-prepared TiO2 NTs were 88 ± 16 nm, 10 ± 2 nm and 491 ± 56 nm, respectively. Such dimensions are affected by the NaF concentration and the applied voltage during processing. Higher NaF concentrations result in the formation of longer and thicker nanotubes. The higher the voltage is, the thicker the nanotubes. The photosensitive anode made from the highly ordered TiO2 NTs has good photo-catalytic property, as can be seen from the test results of ethanol, apple vinegar, sugar and tissue paper decomposition under ultraviolet (UV) radiation. It is concluded that the biophotofuel cell with the TiO2 nanotube photoanode and a Pt cathode can generate electricity, hydrogen and clean water depending on the pH value and the oxygen presence in the solutions. © 2011 Elsevier B.V.

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