【作者】 李靖；

【导师】 林祥钦；

【作者基本信息】 中国科学技术大学 ， 分析化学， 2008， 博士

【摘要】 本论文对导电聚合物在纳米材料领域的应用、聚吡咯纳米复合材料电化学生物传感器的研究进展进行了较为细致的综述，在此基础上，开展了以导电聚吡咯及过氧化聚吡咯和金属纳米复合材料为体系的系列纳米电极电化学传感器的研制、表征与应用研究。主要借助扫描电镜、X-射线光电子能谱及X-射线粉末衍射等表面分析技术以及各种电化学手段，对电极表面构筑的纳米结构及其传感性能进行了研究与表征，并应用于燃料电池（包括甲醇、乙醇、甲醛和O₂）、单胺类神经递质（包括多巴胺、肾上腺素和5-羟色胺）以及其它一些重要的生物活性物质（包括抗坏血酸、尿酸、葡萄糖、还原型辅酶烟酰胺腺嘌呤二核苷酸、肼、羟胺和NO₂^-）的电化学催化与传感测定。详细内容包括如下：以无模板直接电化学法在玻碳电极（GCE）表面制备聚吡咯（PPy）纳米线，得到PPy／GCE。在PPy／GCE上电化学沉积Pt，制备了100 nm大小的Pt纳米簇嵌入在PPy纳米线中的多孔结构复合膜修饰电极，PPy-Pt／GCE。研究发现，PPy-Pt／GCE对甲醇、乙醇、甲醛、O₂和NO₂^-都有很高的电化学催化性能，可望用于制作高灵敏的氧传感器、NO₂^-传感器和高效的氢-氧燃料电池电极。该电极对甲醇的催化氧化，最大电流密度达17．8 mA／cm²，比Pt／GCE提高50％，而且抗CO_ads中毒能力也大大提高。在H₂SO₄溶液中对O₂的催化还原，电流密度达1．3 mA／cm²，还原电位在0．518 V，与Pt／GCE相比，显著提高了催化性能。进而，以PPy-Pt／GCE为基底，利用循环伏安法聚合邻氨基苯酚（OAP）共沉积葡萄糖氧化酶（GOD），制备了葡萄糖传感器（POAP-GOD／PPy-Pt／GCE）。该传感器具有十分优异的生物响应特性，响应时间约7 s，检测限为4．5×10^-7mol／L，米氏常数为23．9 mmol／L，酶催化反应的表观活化能为25．9 kJ／mol，最大响应电流密度达378μA／cm²。由于采用PPy-Pt和POAP-GOD双层纳米复合膜结构，很好地保持了酶的活性，具有良好的灵敏度、重现性和稳定性，能够完全消除抗坏血酸、尿酸和对乙酰氨基酚的干扰。在PPy／GCE上，电化学沉积Au，得到了15 nm大小的Au纳米粒子均匀地分散在PPy纳米线上的Au／PPy纳米复合膜修饰电极，Au／PPy／GCE。该纳米电极对肼、羟胺和NO₂^-都有显著的电催化氧化作用，线性响应范围宽，灵敏度高，检测限低，可用于这三种物质的传感分析。将PPy／GCE在NaOH溶液中过氧化处理得到了过氧化聚吡咯膜修饰电极，PPyox／GCE。以PPyox膜为模板电化学沉积Au，得到了Au纳米阵列电极，nano-Au／PPyox／GCE。以肾上腺素（EP）、多巴胺（DA）、5-羟色胺（5-HT）和尿酸（UA）为分析对象，研究了修饰电极的伏安传感性能，发现纳米Au和PPyox膜的协同效应，使修饰电极对EP、DA、5-HT和UA有较高的电流灵敏度和选择性，对AA有极强的电流抑制作用，因而可以在大量AA存在下，进行选择性测定。最后，在PPyox／GCE上研究了邻苯二酚的电化学行为，并以邻苯二酚为电子媒介体，电催化氧化还原型辅酶烟酰胺腺嘌呤二核苷酸，UA的存在不干扰测定。更多还原

【Abstract】 A detailed review on the applications of conducting polymers in nanomaterials and on the development of polypyrrole （PPy） nanocomposite in electrochemical biosensors was carried out. The research work was focused on fabrication of electrochemical sensors by surface nano-construction using PPy and its overoxidized forms based on metal nanocomposites. Field emission scanning electron microscope, X-ray photoelectron spectroscopy, X-ray diffraction and electrochemical techniques were used to characterize structures and electrochemical sensing properties of these nanoelectrodes. The use of these electrodes in fuel cells （such as methanol, ethanol, formaldehyde and oxygen） and electrochemical sensing of substances involving of monoamine neurotransmitters （such as dopamine, epinephrine and serotonin） and other bioactive molecules （such as ascorbic acid, uric acid, glucose, nicotinamide adenine dinucleotide, hydrazine, hydroxylamine and nitrite） were investigated. The details are as follows:The PPy nanowires modified glassy carbon electrode （PPy/GCE） was directly electrodeposited without additional templates. Then, Pt nanoclusters were electrochemically deposited on PPy/GCE and PPy-Pt composite modified electrode （PPy-Pt/GCE） was obtained. The Pt nanoclusters with diameter of 100 nm were embedded in the PPy nanowires, forming a novel microporous structure nanocomposite. We found that the modified electrode has strongly electrocatalytic activity toward reactions of methanol, ethanol, formaldehyde, O₂ and NO₂^-. Thus, it can be effectively used as high sensitive oxygen sensor and NO₂^- sensor, as well as the anode and cathode in fuel cells. The maximum current density of methanol oxidation reaction was 17.8 mA/cm², which was 1.5 times of that at corresponding Pt/GCE. The CO poisoning effect on the electrode can be significantly reduced. The O₂ reduction reaction at the electrode gave a cathodic peak at 0.518 V in H₂SO₄ solution with current density of 1.3 mA/cm², which is much higher than that of the corresponding Pt/GCE.Then, a novel glucose biosensor （POAP-GOD/PPy-Pt/GCE） was fabricated by co-deposition of o-aminophenol and glucose oxidase on PPy-Pt/GCE. The sensor has superior sensing ability of amperometric response time of 7 s, the detection limit of 4.5×10^-7 mol/L, the maximum current density of 378μA/cm², the activation energy of 25.9 kJ/mol,and Michaelis-Menten constant of 23.9 mmol/L. It demonstrated that the PPy-Pt and POAP-GOD nanocomposite bilayer structure can completely eliminate the interference of ascorbic acid, uric acid and acetaminophen, and well maintain the enzyme activity and stability, enhancing both of the sensitivity and reproducibility.Alternatively, Au nanoparticles were electrochemically deposited on PPy/GCE, generating an Au/PPy nanocomposite modified GCE （Au/PPy/GCE）, on which Au nanoparticles of about 15 nm in diameter were uniformly dispersed on the surface of PPy nanowires. The Au/PPy/GCE exhibited strongly catalytic activity toward the oxidation of hydrazine, hydroxylamine and nitrite. The sensor showed wide linear ranges, high sensitivities and low detection limits in the electrochemical sensing of these species.On the other hand, the conducting PPy film has been overoxidized in NaOH solution, generating a non-conducting PPyox film modified electrode （PPyox/GCE）. Au nanoparticles were electrochemically deposited into the PPyox template and obtained a nano-Au array electrode （nano-Au/PPyox/GCE）. Due to the synergic effect of nano-Au and PPyox template, the nanoelectrode exhibited excellent selectivity and sensitivity toward dopamine （DA）, epinephrine （EP）, serotonin （5-HT） and uric acid （UA） oxidation, which could eliminate the interferences of AA. The sensor has been applied to detect EP, DA, 5-HT and UA in the presence of high concentrations of AA.Finally, the electrochemical behavior of catechol at PPyox/GCE was investigated. The electrocatalytic oxidation of nicotinamide adenine dinucleotide （NADH） mediated by catechol has been examined. The interference of UA with NADH oxidation was eliminated.更多还原