【作者】 宋诗稳；

【导师】 齐广才；

【作者基本信息】 延安大学 ， 分析化学， 2010， 硕士

【摘要】 纳米材料具有独特的电学和化学性能,在电化学及电分析化学领域有着广阔的应用前景,而以普鲁士蓝为代表的多核金属铁氰化物一直是人们研究的热点。在制备化学修饰电极方面,通过改进制备方法来提高这类修饰电极的稳定性与电催化活性是该领域的研究热点之一。本论文采用电化学方法制备了Nano-CuHCF、Nano-NiHCF/PPyox、Nano-PB/PPyox、Nano-NiHCF/PB及HCF/PPy、MWNT/HCF/PPy六种金属铁氰化物修饰电极,采用电化学方法及扫描电镜技术研究了以上修饰电极的电化学性质及其对相关物质的电催化活性。其次,研究了纳米CeO₂以及多壁碳纳米管对违禁药物克伦特罗的电催化测试性能,建立了相应的电化学检测方法。本研究工作在改善修饰电极稳定性、拓宽其在电分析化学领域的实际应用方面具有潜在的应用价值。主要内容如下:1、采用循环伏安法,从含有EDTA和HAuCl4的沉积液中制备了Nano-CuHCF、Nano-PB/PPyox修饰的复合陶瓷碳电极;在EDTA存在下将Nano-NiHCF沉积于PPyox表面,制备了Nano-NiHCF/PPyox修饰的复合陶瓷碳电极,并研究了制备上述三种电极的实验条件及修饰电极的电催化性能。采用电化学与扫描电镜技术对可能的机理进行了研究,并优化了制备修饰电极的实验条件。结果表明:EDTA控制了金属铁氰化物的成核速率与沉积速率,而沉积于电极表面的金粒子为金属铁氰化物的生成提供了成核点,在EDTA与HAuCl₄的协同作用下,电极表面沉积了均匀致密的薄膜,而PPyox膜的存在进一步提高了PB在电极表面的沉积速率。Nano- CuHCF与Nano-NiHCF/PPyox对N₂H₄具有较强的电催化活性,Nano-PB/PPyox对H₂O₂的电化学还原也表现出了较强的催化活性,计时安培法测得Nano-CuHCF/ CCE、Nano-NiHCF/PPyox/CCE、Nano-PB/PPyox/CCE修饰电极对N₂H₄和H₂O₂的异相催化反应速率常数分别为1.4×10⁴、4.83×10⁴及7.73×10³ L·mol^-1·s^-1,灵敏度分别为194.0、110与220.0μA·(mmol·L^-1)^-1。2、在EDTA存在下,以复合陶瓷碳电极为基础电极在含有Ni²⁺、Fe³⁺、K₃Fe（CN）₆的混合溶液中采用循环伏安法制备了Nano-NiHCF/PB复合膜修饰电极,并研究了该电极的电化学性质及其对H₂O₂的电催化活性。结果表明,Nano-NiHCF/PB循环伏安图上的两对氧化还原峰与普鲁士蓝的两对特征氧化还原峰峰电位有所不同,这表明该修饰电极并不是铁氰化镍和普鲁士蓝的简单混合,而是生成了混合多核金属铁氰化物,Ni²⁺占据了PB格子中的某些点位。与单一PB修饰电极相比,该修饰电极在酸性、中性及弱碱性溶液中均具有很好的稳定性,且对H₂O₂的还原有较强的电催化活性。安培法检测的线性范围为7.94×10⁽-6 2.30×10⁽-2 mol·L^-1,检出限为2.50×10^-6 mol·L^-1,检测灵敏度为77.50μA·(mmol·L^-1)^-1。3、采用循环伏安法在裸复合陶瓷碳电极及多壁碳纳米管滴涂的复合陶瓷碳电极表面电沉积了HCF/PPy,制备了HCF/PPy和MWNT/HCF/PPy修饰电极,研究了这两种修饰电极的电化学和电催化性能。实验表明,上述两种修饰电极分别对H₂O₂和NO₂^-的还原具有较强的电催化活性。安培法检测这两种物质的线性范围分别为2.0×10^-6 2.4×10⁽-3 mol·L^-1和1.5×10^-6 1.8×10^-3 mol·L^-1,检出限分别为7.0×10⁽-7 mol·L^-1与3.0×10^-7 mol·L^-1,检测灵敏度为61.30与81.39μA·(mmol·L^-1)^-1,响应时间均小于5 s。4、制备了MWNT修饰的碳糊电极,并采用全固相法合成了纳米CeO2,制备了Nano-CeO2修饰的碳糊电极。研究了克伦特罗在以上两种修饰电极上的电化学行为。与裸碳糊电极相比,这两种修饰电极能显著提高测定克伦特罗的灵敏度,据此建立了测定克伦特罗的微分脉冲伏安法,该法已用于模拟尿样与模拟血样中克伦特罗含量的测定。微分脉冲伏安法检测克伦特罗的线性范围分别为5.0×10⁽-9 6.0×10-6 mol·L^-1和2.0×10⁽-9 1.0×10⁽-5 mol·L^-1,检出限分别为2.5×10⁽-9 mol·L^-1与7.0×10^-10 mol·L^-1。更多还原

【Abstract】 Nanoparticles provide unique electrical and chemical properties and have attracted much research interest, such as electrochemistry and electroanalytical chemistry. Among various electron transfer mediators, metal hexacyanoferrates （MHCF）, a class of polynuclear metal hexaeyanoferrate, have attracted much attention since the pioneering work of Prussian blue （PB）. To improve the stability and analytical performance of the modified electrodes, convenient methods were investigated in the preparation of chemically modified electrodes. Six kinds of hexacyanoferrates including Nano-CuHCF, Nano-NiHCF/PPyox, Nano-PB/PPyox, Nano-NiHCF/PB, HCF/PPy and MWNT/HCF/ PPy were electrochemical deposition on carbon ceramic composite electrodes （CCE）. The electrochemical and electrocatalytic activity of the above electrodes were investigated using electrochemical and scanning electron microscopy methods. Additionally, two kinds of carbon paste modified electrodes （CPE） including Nano- CeO2/CPE and multi-walled carbon nanotubes modified CPE were fabricated. These two kinds of nanoparticles modified CPE were used in the determination of clenbuterol and established the corresponding electrochemical detection methods. The research possessed potential applications in improving the stability and broaden the analytical chemistry of modified electrodes.This thesis carefully studied the preparation, characterization, electrochemical properties and electrocatalytic activity of the following modified electrodes. The main contents were as follows:1. Two kinds of metal hexacyanoferrates modified CCE, Nano-CuHCF/CCE and Nano-PB/PPyox/CCE, were fabricated using cyclic voltammetry from the solution containing HAuCl4 and EDTA. Additionally, Nano-NiHCF was deposited on the surface of PPyox modified CCE in the presence of EDTA. The possible mechanism was investigated by using electrochemical and SEM techniques and the electrodeposition conditions were optimized. The results showed that, EDTA controlled the efficient concentration of mental ions in solution, while the gold particles deposited on the electrode surface provided heterogeneous crystal seeds once they had been produced and thus speeded up the rate of MHCF deposition. Under the synergic action of EDTA and HAuCl4, uniform and compact films were formed. Additionally, the presence of PPyox film further enhanced the deposition rate of PB on the electrode surface. The Nano-CuHCF/CCE and Nano-NiHCF/PPyox/CCE had strong electrocatalytic activity toward the oxidation of hydrazine, while the Nano-PB/PPyox/CCE had electrocatalytic activity toward the reduction of H₂O₂. The heterogeneous catalytic reaction rate constants by chronoamperometry were 1.4×10⁽4 for Nano-CuHCF, 4.83×10⁽4 for Nano-NiHCF/ PPyox, and 7.73×10⁽3 L·mol^-1·s^-1 for Nano-PB/PPyox with the sensitivity of 194.0、110.0 and 220.0μA·(mmol·L^-1)^-1, respectively.2. A Nano-NiHCF/PB film modified CCE was typically fabricated in the presence of EDTA, Ni²⁺, Fe³⁺ and K₃Fe（CN）6 using cyclic voltammetry method. The electrochemical properties and electrocatalytic activity toward H₂O₂ was studied. The results showed that, the Nano-NiHCF/PB exhibited two pair of redox peaks, which were quite different from the redox peaks of PB, indicating that the mixed material wasn’t seems to be a simple mixture of hexacyanoferrates of nickel and iron, that Ni²⁺ occupies certain position of PB lattice. Compared with single metal hexacyanoferrates electrodes, the Nano-NiHCF/PB/ CCE exhibited perfect stability in acidic, neutral and weak alkaline solution and showed high electrocatalytic activity toward the reduction of H₂O₂. The calibration curve was over the range of 7.94×10^-6 to 2.30×10^-2 mol·L^-1 with a detection limit of 2.50×10^-6 mol·L^-1, and the sensitivity to H₂O₂ reduction was 77.50μA·(mmol·L^-1)^-1.3. Fe（CN）64- doped polypyrrole composite film modified electrode was electro- chemical deposited on bare CCE and multi-walled carbon nanotubes dropped CCE using cyclic voltammetry, and the HCF/PPy/CCE and MWNT/HCF/PPy/CCE were fabricated. The electrocatalytic properties of both modified electrode were studied. Experiments showed that the two kinds of modified electrodes had strong electrocatalytic activity toward the reduction of H₂O₂ and NO₂^-. Amperometric detection of H₂O₂ and NO₂^- were in the linear ranges of 2.0×10^-6 2.4×10⁽-3 mol·L^-1 and 1.5×10^-6 1.8×10^-3 mol·L^-1, the detection limits were 7.0×10^-7 and 3.0×10-7 mol·L^-1 with the sensitivity of 61.30 and 81.39μA·(mmol·L^-1)^-1, respectively, and both of the corresponding time were less than 5s.4. Nano-CeO2 was synthesized by all-solid-phase method and a Nano-CeO2/CPE was prepared. On the other hand, a MWNT/CPE was also prepared. Comparing with that of a bare electrode, the current of clenbuterol was greatly increased at above modified electrodes. Based on this, differential pulse voltammetric methods for the determination of clenbuterol were established. The methods were applied in the determination of clenbuterol in simulated urine and blood samples. Under the optimum conditions, linear dependences of the catalytic current versus the concentration of clenbuterol were obtained in the ranges of 5.0×10^-9 6.0×10⁽-6 and 2.0×10^-9 1.0×10^-5 mol·L^-1 with the detection limits of 2.5×10^-9 and 7.0×10^-10 mol·L^-1.更多还原