Preparation and electrochemical applications of tellurium-based nanomaterials
Date Issued
2012
Date
2012
Author(s)
Tsai, Hsiang-Yu
Abstract
The thesis consisted two parts: the first part focused on the electrochemical detection of dopamine using tellurium-nanowire-coated glassy carbon electrode; the second part is about the growth of 3D, Te/Pt nanonetworks on carbon fiber microelectrode as the catalyst on miniaturized direct methanol fuel cells (DMFCs). For the dopamine detection part, tellurium-nanowire-coated glassy carbon electrodes (TNGCEs) were prepared by direct deposition of tellurium nanowires, 600 ± 150 nm in length and 16 ± 3 nm in diameter, onto glassy carbon electrodes, which were further coated with Nafion to improve their selectivity and stability. Compared to the GCE, the TNGCE is more electroactive for DA, and its selectivity toward DA over ascorbic acid (AA) and uric acid (UA) is also greater. By applying differential pulse voltammetry, the TNGCE provides a limit of detection of 1.0 nM for DA in the presence of 0.5 mM AA and UA and gives good linearity of the oxidation current against the concentration of DA (5.0 nM to 1.0 uM). TNGCEs have been applied to determine the concentration of dopamine to be 0.59 ± 0.07 uM in PC12 cells. For the miniaturized DMFC part, Te/Pt nanonetworks decorated carbon fiber microelectrodes (Te/PtCFMEs) have been fabricated by galvanic replacement reaction between Te nanonetworks and PtCl62- ion and employed for catalysis of methanol oxidation in direct methanol fuel cells (DMFCs). As anodic catalyst in DMFC, Te/PtCFMEs provide high electrochemical active surface area (129.2 cm2 g-1), good catalytic activity (1.2 A mg-1), great current density (20.0 mA cm-2), long durability and acceptable tolerance toward the poisoning species (If/Ib > 1.3) for methanol oxidation in 0.5 M sulfuric acid containing 1 M methanol. By applying multiple carbon fibers, the CFME can generate even higher electrooxidative current.
Subjects
Te nanowires
Pt nanomaterials
electrochemistry
dopamine
fuel cells
Type
thesis
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