Browsing by Author "Tung, Sze-Ping"

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(110)-Exposed Gold Nanocoral Electrode as Low Onset Potential Selective Glucose Sensor
(2010-10-01)
Cheng, Ta-Ming
;
Huang, Ting-Kai
;
Lin, Huang-Kai
;
Tung, Sze-Ping
;
Chen, Yu-Liang
A straightforward electrochemical deposition process was developed to grow gold nanostructures, including nanocoral, nanothorn, branched belt, and nanoparticle, on carbon electrodes by reducing HAuCl(4) under constant potentials in mixtures containing CTAC and/or NaNO(3). Among the nanostructures, the quasi-one-dimensional nanocoral electrode showed the highest surface area. Because of this, it provided excellent electrochemical performances in cyclic voltammetric (CV) studies for kinetic-controlled enzyme-free glucose oxidation reactions. In amperometric studies carried out at 0.200 V in PBS (pH 7.40, 0.100 M), the nanocoral electrode showed the highest anodic current response. It also offered the greatest sensitivity, 22.6 mu AmM(-1)cm(-2), an extended linear range, 5.00 x 10(-2) mM to 3.00 x 10(1) mM, and a low detection limit, 1.00 x 10(1) mu m among the electrodes investigated in this study. In addition, the glucose oxidation by the nanocoral electrode started at -0.280 V. more negative than the one of using a commercial Au electrode as the working electrode. This is attributed to the presence of exposed Au (110) surfaces on the electrode. The feature was applied to oxidize glucose selectively in the presence of ascorbic acid (AA) and uric acid (UA), common interferences found in physiological analytes. With an applied voltage at -0.100 V. the AA oxidation (started at -0.080 V) can be avoided while the glucose oxidation still provides a significant response.
(110)-Exposed Gold Nanocoral Electrode as Low Onset Potential Selective Glucose Sensor
(2010-10-01)
Cheng, Ta-Ming
;
Huang, Ting-Kai
;
Lin, Huang-Kai
;
Tung, Sze-Ping
;
Chen, Yu-Liang
A straightforward electrochemical deposition process was developed to grow gold nanostructures, including nanocoral, nanothorn, branched belt, and nanoparticle, on carbon electrodes by reducing HAuCl(4) under constant potentials in mixtures containing CTAC and/or NaNO(3). Among the nanostructures, the quasi-one-dimensional nanocoral electrode showed the highest surface area. Because of this, it provided excellent electrochemical performances in cyclic voltammetric (CV) studies for kinetic-controlled enzyme-free glucose oxidation reactions. In amperometric studies carried out at 0.200 V in PBS (pH 7.40, 0.100 M), the nanocoral electrode showed the highest anodic current response. It also offered the greatest sensitivity, 22.6 mu AmM(-1)cm(-2), an extended linear range, 5.00 x 10(-2) mM to 3.00 x 10(1) mM, and a low detection limit, 1.00 x 10(1) mu m among the electrodes investigated in this study. In addition, the glucose oxidation by the nanocoral electrode started at -0.280 V. more negative than the one of using a commercial Au electrode as the working electrode. This is attributed to the presence of exposed Au (110) surfaces on the electrode. The feature was applied to oxidize glucose selectively in the presence of ascorbic acid (AA) and uric acid (UA), common interferences found in physiological analytes. With an applied voltage at -0.100 V. the AA oxidation (started at -0.080 V) can be avoided while the glucose oxidation still provides a significant response.
Electrochemical growth of gold nanostructures on carbon paper for alkaline direct glucose fuel cell
(2012)
Tung, Sze-Ping
;
Huang, Ting-Kai
;
Lee, Chi-Young
;
Chiu, Hsin-Tien
;
應用化學系
Au nanocorals and nanoparticles were grown on carbon papers via a simple two-electrode electrochemical deposition process by reducing HAuCl(4) under constant potentials in mixtures containing cetyltrimethylammonium chloride (CTAC) and/or NaNO(3). Electrochemical characterizations showed that the nanocoral electrode exhibited high surface area and high electrocatalytic activity towards glucose oxidation in alkaline media. These Au nanostructures were employed as anodes and assembled with anion exchange membranes and Pt cathodes for alkaline direct glucose fuel cell (DGFC) investigations. Open-circuit voltages (OCVs) of the Au nanocoral and nanoparticle electrodes were 0.64 V and 0.61 V, and their maximum power densities were 0.847mWcm(-2) and 0.336mWcm(-2), respectively. The cells showed stable output over 5 h with a small decrease in OCV (6.9%). The electrodes could be refreshed after electrochemical reduction steps.
Glucose sensing by electrochemically grown copper nanobelt electrode
(2009-11-15)
Huang, Ting-Kai
;
Lin, Kuan-Wen
;
Tung, Sze-Ping
;
Cheng, Ta-Ming
;
Chang, I-Chun
A simple design of growing Cu nanobelt (NB) electrode for glucose sensing is presented. Cu NBs were grown directly on carbon electrodes by using electrochemical deposition. The average width, thickness and length of the NBs were about 50 nm, 20 nm and several tens of micrometers, respectively. Cyclic voltammetric (CV) experiments showed that a Cu NB electrode grown by a reduction charge of 0.5 C on a substrate of 0,018 cm(2) enhanced glucose oxidation ability. For glucose sensing, the electrode exhibited a high sensitivity of 79.8 mu A/mM and a measurable detection limit of 10 mu M in amperometric detection. (C) 2009 Elsevier B.V. All rights reserved.