【作者】 陈菲；

【导师】 郭金学；

【作者基本信息】 青岛科技大学 ， 无机化学， 2010， 硕士

【摘要】 超声波作为一种新的合成方法与传统合成方法相比具有反应温度低、时间短以及条件温和等特点。本论文利用超声波合成法成功制备了MnWO4和CNT-CeO2两种纳米材料并分别研究了它们的性质。我们以钨酸盐为先驱物,采用不同的表面活性剂,在超声波条件下成功制备了不同形貌的纳米钨酸锰。本工作研究了在实验中采用不同的表面活性剂对于纳米钨酸锰最终形貌的影响。利用粉末XRD、SEM、EDS、FTIR以及UV-vis等表征技术对所制备的纳米钨酸锰样品进行了表征。基于其良好的光化学性能,本工作开展了纳米钨酸锰对于有机染料罗丹明B的光降解实验。实验结果发现,纳米钨酸锰对于有机染料罗丹明B的光降解具有较好的催化作用,有望在有机染料废水处理领域得到应用。本工作还研究了纳米钨酸锰的电化学性质。实验发现,经MnWO4和壳聚糖(CHIT)修饰的玻碳电极能够增强亚铁离子和铁离子氧化还原反应对之间的电子转移。将此修饰电极MnWO4/CHIT/GCE电极的表面吸附牛血红蛋白(Hb)后即可构成对于H2O2具有良好催化效果的传感器,可用于测定溶液中H2O2的浓度,其线性范围为5.0×10-6 - 4.5×10-4 M,检测限为1.0×10-6 M。CNT-CeO2复合纳米材料的合成是以硝酸铈铵为先驱物,以乙二醇作为表面活性剂,在超声波条件下合成纳米CeO2颗粒沉积在碳纳米管载体上得到的。利用粉末XRD、SEM、EDS以及FTIR等表征技术对所制备的CNT-CeO2复合纳米材料进行了表征。基于纳米CeO2的高比表面积和碳纳米管良好的导电性,本工作将其固定在玻碳电极的表面制成CNT-CeO2/CHIT/GCE修饰电极,并利用循环伏安(CV)以及电化学阻抗波谱分析(EIS)研究了此修饰电极的电化学性质。电化学实验结果表明,CNT-CeO2/CHIT/GCE修饰电极具有良好的电化学活性,能够增强亚铁离子和铁离子氧化还原反应对之间的电子转移,在其表面吸附牛血红蛋白后对溶液中H2O2的分解反应具有良好的催化性能,在H2O2浓度为5.0×10-6 - 5.0×10-4 M的范围内,Hb/CNT-CeO2/CHIT/GCE电极的电催化信号与溶液中H2O2浓度呈线性关系。因此,超声法合成的CNT-CeO2复合纳米材料可用于构建一种新型的H2O2传感器,其检测限为1.0×10-6 M。另外为促进两种纳米材料在燃料电池领域的应用,本工作采用循环伏安电沉积法将氯铂酸分别沉积在MnWO4/CHIT/GCE复合电极和CNT-CeO2/CHIT/GCE复合电极的表面,形成Pt/MnWO4/CHIT复合膜和Pt/CNT-CeO2/CHIT复合膜,应用线性扫描伏安法检测所制得Pt/MnWO4/CHIT复合膜和Pt/CNT-CeO2/CHIT复合膜对甲醇氧化的催化活性。初步的实验结果表明两种复合膜对甲醇均具有较高的电催化活性。更多还原

【Abstract】 Different from the routine methods, the new ultrasonic-induced synthesis approach has many advantages, such as low reaction temperature, short reaction time, and mild reaction conditions. In this thesis, MnWO4 nanocrystals and CNT-CeO2 nanocomposites have been successfully achieved by the ultrasonic technique. Their properties and applications have also been studied in our work.MnWO4 nanostructures with different morphologies have been prepared using inorganic salts as precursors via sonochemical process. In this work, the influence of the different surfactants on the morphology-control of MnWO4 nanostructures was investigated. The as-prepared MnWO4 nanocrystals were characterized by X-ray diffraction(XRD), scanning election microscopy(SEM), energy dispersive spectroscopy (EDS), fourier transform infrared(FT-IR), UV-vis spectroscopy and other techniques. Because of its good photocatalytic property, the as-synthesized MnWO4 had been introduced for the photodegradation of rhodamine B (RhB). The results indicated that MnWO4 had excellent photocatalytic property for the degradation of RhB and it had potential applications in the organic dyestuff and water treatment region. The electrochemical property of MnWO4 nanocrystals had also been studied. It is indicated that the glass carbon electrode (GCE) moditied with MnWO4 nanocrystals and CHIT could enhance electron transfer for its heme Fe(III) to Fe(II) redox couple. The MnWO4/CHIT/GCE electrode was further used as efficient supports for the immobilization of hemoglobin (Hb) to fabricate a novel biosensor. The biosensor showed an excellent bioelectrocatalytic activity towards H2O2 with a linear range from 5.0×10-6 to 4.5×10-4 M, and the detection limit of the sensor was 1.0×10-6 M at 3σ.CNT-CeO2 nanocomposites has been achieved by a cheap and simple ultrasonic technique using (NH4)2Ce(NO3)6 as precursors and the ethylene glycol (EG)-assisted. The as-prepared CNT-CeO2 nanocomposites were characterized by X-ray diffraction(XRD), scanning election microscopy(SEM), Energy Dispersive Spectroscopy (EDS), fourier transform infrared(FT-IR), and other techniques. Because of the high surface area of CeO2 and the good electrical conductivity of CNTs, they were immobilized on glass carbon electrode (GCE) to fabricate CNT-CeO2 /CHIT/GCE electrode. Then the electrochemical property of this modified electrode was studied by cyclic voltammetry and electrochemical impedance spectroscopy. The electrochemical results indicated that CNT-CeO2/CHIT/GCE electrode could enhanced electron transfer for its heme Fe(III) to Fe(II) redox couple. When Hb was cast on its surface, the modified electrode showed good electrocatalytic activity towards H2O2 reduction. The catalytic reduction peak current of Hb/CNT-CeO2/CHIT/GCE film increased linearly with the concentration of H2O2 in a linear range from 5.0×10-6 to 5.0×10-4 M. Hence, CNT-CeO2 nanocomposites achieved by ultrasonic technique can be fabricated a novel biosensor to H2O2. Its detection limit was 1.0×10-6 M at 3σ.Moreover, in order to study the potential applications of these materials in fuel cell, H2PtCl6 was electrodeposited on the MnWO4/CHIT/GCE electrode and CNT-CeO2 /CHIT/GCE electrode by cyclic voltammetry to form MnWO4/CHIT film and CNT-CeO2 /CHIT film. The electrochemical oxidation of methanol on the MnWO4/CHIT film and CNT-CeO2 /CHIT film was studied by cyclic voltammetry respectively. The primary results demonstrated that these two films had a good electorcatalytic activity for the methanol oxidation reaction.更多还原