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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/71377

    Title: Adsorption and Electrochemical Polymerization of Pyrrole on Au (100) Electrode as Examine by In Situ Scanning Tunneling Microscopy;Adsorption and Electrochemical Polymerization of Pyrrole on Au (100) Electrode as Examine by In Situ Scanning Tunneling Microscopy
    Authors: 柯艾妲;Khairunnisa,Alda
    Contributors: 化學學系
    Keywords: Polypyrrole;Pyrrole;Scanning Tunneling Microscopy;Au(100);Polymerization;Polypyrrole;Pyrrole;Scanning Tunneling Microscopy;Au(100);Polymerization
    Date: 2016-08-26
    Issue Date: 2016-10-13 12:47:40 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 摘要
    吸附及其聚合過程。由 STM的結果顯示,吡咯與硫酸氫根會在 0.55V(vs. RHE)於金(100)上呈現
    共吸附的結構( 4√2 x 4 √2 ),其覆蓋度為 0.125。當電位在大於 0.8V 時進行掃描則會使聚吡咯
    呈現彎曲結構。循環伏安法(CV)顯示在 0.1M硫酸中加入 30mM吡咯會在 0.42V得到一對可逆
    的吡咯吸脫附峰,而於 0.8V 則有一個氧化電流出現,此為吡咯開始聚合的特徵。此外,在金
    高解像得到其結構。根據 STM 顯示,在硫酸下由電位掃描聚合的聚吡咯會同時具有 α-α 耦合
    以及少量 α-β 耦合的情況。當聚吡咯氧化後,硫酸氫根會以陰離子的形式圍繞在聚吡咯鏈旁和
    CV 和 STM 中,在 pH4,0.1M 硫酸鉀(以硫酸調節 pH)中形成之聚吡咯,其寡聚物和聚吡咯之
    結構與 0.1M硫酸環境下聚合之結果相似,但高 pH值下聚吡咯之形成較緩慢。而從 FTIR結果
    顯示其兩種電解質皆有相同吸收帶於1586、1280、900和820 cm-1,此為C=C和C-N鍵之伸縮
    ;Studies the molecular structures and conformation of polypyrrole (Ppy) are important to the understanding of their electrochemical properties as a conducting polymer. This thesis describes, for the first time, in situ scanning tunneling microscopy (STM) imaging the molecular adsorption and polymerization of pyrrole on Au (100) single crystal electrode. Obtained results reveal highly ordered Au(100) – (4 √2 x 4 √ 2 x pyrrole + bisulfate (HSO4- ) at 0.55 V vs. reversible hydrogen electrode (RHE) with 0.125 coverage. Continuous STM scanning at E > 0.8V discerns Ppy polymers assuming winding structures. Meanwhile, voltammetric results recorded in 0.1 M H2SO4 containing 30 mM pyrrole show a pair of reversible peak at 0.42 V, attributed to pyrrole adsorption. The oxidation current increases notably at 0.8 V, as pyrrole molecule is oxidized and polymerized. By contrast, STM reveals a disordered pyrrole adlayer on Au(111) electrode and the voltammetry result shows mostly featureless profile.
    Modification of Au (100) with an iodine adlayer can strengthen interaction between Ppy and Au(100), which helps in achieving high-resolution STM images. Aided by molecular resolution STM images, one recognizes that the as-prepared Ppy can have linkages of not only α-α, but also α-β coupling, although the latter is relatively unimportant. After Ppy is oxidized, HSO4- anions are drawn into the film by positively charged Ppy. This interaction generates Ppy with crooked molecular structure in syn or anti conformations. CV and STM results are also obtained with Ppy formed in pH 4 0.1 M K2SO4 (adjusted by adding H2SO4), revealing oligomer pyrrole and Ppy molecules structurally similar to those seen in 0.1 M H2SO4,
    although the rate of polymerization was slow in the higher pH medium. FTIR results obtained with the as-prepared Ppy have same absorption bands at 1586, 1280, 900, and 820 cm-1, which are ascribed to stretching of C=C and C-N bonds and bending of C-H bond
    without presence C=O functional group. Thus, these IR results suggest that both electrolytes can have the ideal molecular structure of Ppy.
    Appears in Collections:[化學研究所] 博碩士論文

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