【作者】 尹晓娟；

【导师】 褚道葆；

【作者基本信息】 安徽师范大学 ， 有机化学， 2006， 硕士

【摘要】 直接甲醇燃料电池（DMFC）由于其燃料来源丰富、价格便宜、运输和储存较安全等优点而受到广泛重视。然而甲醇有相当高的毒性。因此,要想实现DMFC在诸如手机、笔记本电脑等可移动电源领域的应用,必须探索寻找新的液体燃料以替代有毒性的甲醇。其中乙醇很易从农作物中大量生产,来源广泛,又无毒,因此乙醇燃料电池的研究具有很大的应用潜力。但乙醇完全电化学氧化需要C-C键断裂,其氧化过程涉及到更多的中间产物,致使DEFC的实际应用发展速度一直很缓慢。因此,研制和发展高催化活性、抗中毒能力强的新型的催化剂已成为当前DEFC发展的关键技术。本文采用电合成前驱体Ti（OEt）₄直接水解法和电化学扫描电沉积制备活性高的nanoTiO₂-CNT/Pt、nanoTiO₂-CNT-PAn/Pt多组分复合纳米催化剂,并利用TEM、XRD和SEM技术表征了催化剂晶型、晶粒大小及表面形貌,采用电化学方法评价了多组分复合纳米催化剂对乙醇氧化的电催化活性和稳定性。主要研究结果如下:第一部分:采用循环伏安（CV）扫描电沉积方法制备出高分散的nanoTiO₂-CNT/Pt催化剂,利用电化学方法评价了该催化剂对乙醇氧化的电催化活性和稳定性。TEM、XRD和SEM技术表征了修饰在nanoTiO₂-CNT膜上的Pt催化剂颗粒的大小、分散状态。研究结果表明,纳米Pt粒子分散在nanoTiO₂-CNT复合膜表面,电化学活性表面积达到51.8 m²·g^-1。nanoTiO₂-CNT/Pt催化剂对乙醇的电催化氧化呈现出很好的活性和稳定性,Pt载量为0.32 mg·cm^-2时,常温常压下乙醇氧化起始电位为90 mV,在正扫方向的两个氧化峰和负扫方向的一个氧化峰的峰电流分别达到115 mA·cm^-2、113 mA·cm^-2和75 mA·cm^-2。这主要是由于Pt和nanoTiO₂、CNT之间的协同催化作用使乙醇氧化中间产物的毒化物种易氧化成最终产物。第二部分:采用电氧化聚合和扫描电沉积方法制备nanoTiO₂-CNT -PAn膜载Pt（nanoTiO₂-CNT-PAn/Pt）四组分复合纳米催化剂,探讨了复合纳米催化剂对乙醇直接电氧化的催化活性和稳定性。通过CV、线性扫描伏安和计时电流法实验结果比较表明,正扫时乙醇氧化峰电位分别为0.65 V和0.96 V,氧化峰电流密度分别为173 mA·cm^-2和190 mA·cm^-2。在25℃～55℃温度范围更多还原

【Abstract】 Recently developed direct methanol fuel cell has been received widespread attention due to the abundant source, the low price, the safety of the storage and transportation of the fuel. However, the question of the toxicity of methanol remains crucial, such as portable electronic devices（laptop computers, cellular phones）. Another alternative is to use other alcohols presenting negligible or very low chemical toxicity which is essential, at least for some applications. On the other hand, certain countries with abundant biomass resources are producing significant amounts of ethanol, which is a convenient, cheap and relatively nontoxic liquid fuel. As an alternative fuel, ethanol is safer and exhibits higher energy density than methanol. Thus, it is possible to be applied for the fuel in the fuel cell. But, one of the problems is that the oxidation of ethanol is not as easy as the oxidation of methanol, mainly because of the presence of the C-C bond. It is clear that ethanol electro-oxidation involves more intermediates and products than that of methanol, and thus the actual performance obtained are slightly lower than those observed with methanol. It is key techniques in DEFC to find with the composite catalysts have good electrocatalytic activity and resistant ability to poisoning for the ethanol oxidation. The good electrocatalytic active nanoTiO₂-CNT/Pt, nanoTiO₂-CNT-PAn/Pt composite nanostructural catalysts were prepared by the precursor Ti（OEt）₄ directly hydrolyzed and cyclic voltammetry electrodepositing method. TEM, XRD and SEM results show the size, crystallinity and surface character of the catalysts. The electrocatalytic activitics and stability for the ethanol oxidation were evaluated with the electrochemical techniques. The main result obtained are as follows:Part one: electrochemical deposition method by cyclic voltammetry（CV） to prepare the nanoTiO₂-CNT/Pt, and the composite electrocatalysts were characterized to study those composition and those electrochemical behavior by CV. The electrocatalytic activitics and stability for the ethanol electrooxidation更多还原