【作者】 曹延鑫；

【导师】 贾梦秋；

【作者基本信息】 北京化工大学 ， 材料学， 2008， 硕士

【摘要】 以有机小分子醇为燃料的直接醇类燃料电池(DAFC)是近年来新开发的一类燃料电池,对有机小分子的电催化研究无论是在基础研究还是在应用方面的都有重要的价值。开发出高性能的有机小分子电催化剂已成为直接醇类燃料电池的研究重点。实验研究表明,导电聚合物聚苯胺(PANi)具有比表面积高、环境稳定性良好以及较高的电导率等特征,将其作为载体材料,沉积、分散具有催化活性的Pt、Sn等金属,制备出的贵金属(Pt、Sn)修饰聚苯胺复合电极X-PANi/Pt(X=Pt、PtSn),对甲醇、乙醇等有机小分子呈现了很高的电催化活性。本实验研究了甲醇在PtSn-PANi/Pt电极上的氧化行为以及影响PtSn-PANi/Pt催化活性的制备因素;乙醇在Pt-PANi/Pt电极上的氧化行为以及影响Pt-PANi/Pt电极催化活性的制备因素。实验利用循环伏安法(CV)、交流阻抗(EIS)、扫描电镜(SEM)等表征手段,研究了脉冲电位法(PPM)制备高电化学活性纳米纤维聚苯膜电极的电化学参数对聚苯胺膜电极(PANi/Pt)电活性的影响,研究得到了最优化的电化学参数。SEM结果表明,采用脉冲极化方法制备的聚苯胺膜成纤维网状结构,膜层机械性能稳定不易脱落,比表面积高,适宜作为催化剂载体材料。采用脉冲电位法和恒电位法制备了PtSn-PANi/Pt电极,对甲醇的电氧化行为进行了研究,结果表明PtSn-PANi/Pt电极对甲醇具有较高的电催化活性,金属Sn的加入提高了复合电极的抗毒化能力,提高了电极的稳定性和使用寿命。同时论文还对Pt和Sn的沉积比例对PtSn-PANi/Pt电极催化活性的影响进行了研究。采用脉冲电位法制备了Pt微粒修饰聚苯胺膜电极,研究了乙醇在电极上的电氧化行为。通过比较聚苯胺膜电极(PANi/Pt)和Pt-PANi/Pt电极在乙醇的酸性溶液CV曲线,得出聚苯胺对乙醇没有催化作用。论文还研究了铂的沉积量、反应温度,以及金属铂的沉积方法对Pt-PANi/Pt电极催化氧化乙醇的影响。乙醇在酸性条件下电氧化,CV曲线有3个特征峰;实验温度在40℃以上时,Pt-PANi/Pt电极对乙醇具有较高的催化活性;Pt微粒的沉积方法对电极的催化活性有显著影响。更多还原

【Abstract】 Direct alcohols fuel cell (DAFC) has been intensively researched and developed in recent years. It is significant to study on electro-catalysis of micromolecule alcohols, not only of fundamental research but practical application. It is necessary to develop new catalysts with high performance for electrooxidation of micromolecule alcohols.Polyaniline, one kind of conducting polymers, with porous structure and high surface area, is usually used as matrix to incorporate matel particles possessing catalytic activity, such as Pt, Sn, to prepare X-modified polyaniline electrodes, X-PANi/Pt (X=Pt, PtSn). It is proved that X-PANi/Pt has a high efficiency in electrooxidation of small molecules such as methanol, ethanol and formic acid. In this paper, studies on oxidation phenomena of methanol on PtSn-PANi/Pt electrode, ethanol on Pt-PANi/Pt electrode, and effect of preparing process on electrocatalytic properties, were carried out. Effect of electrochemical parameters on electrocatalytic properties of PANi/Pt electrode prepared with pulsating potential method (PPM) was investigated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microcopy (SEM). The results of SEM indicated that the mesh structural PANi films prepared with PPM were provided with splendid mechanical character and high specific surface area, appropriate to be the matrix to load activators.PtSn-PANi/Pt electrodes were prepared with pulsating potential method and constant potential method respectively. The results of CV and EIS showed that the PtSn-PANi/Pt electrode possessed higher higher catalytic activity to methanol, as Sn improved antitoxic stability of the eletrode and prolong service life of the eletrode. And Effect of the load radio of Pt and Sn on electrocatalytic properties of PtSn-PANi/Pt electrode was also researched.Pt-modified PANi film electrode was prepared by PPM and electrooxidation of ethanol on PtSn-PANi/Pt electrode was investigated. The rusult was received that PANi had no catalytic activity on ethanol by comparing the curves of cyclic voltammetry tests of PANi/Pt and Pt-PANi/Pt electrode in the acid solution. Effect of load of Pt, temperature of reaction and deposition method on catalytic activity on ethanol was studied. Three characteristic peaks emerged in the curves of cyclic voltammetry when ethanol electrooxidized in the acid solution. When the temperature was 40℃, Pt-PANi/Pt electrode possessed high catalytic activity. The deposition method of Pt affected the catalytic activity of electrode distinctly.更多还原