聚苯胺在直接甲醇燃料电池中的应用及其电催化性能的研究

发布时间：2018-03-28 22:31

本文选题：聚苯胺　切入点：功能化　出处：《重庆大学》2015年硕士论文

【摘要】：直接甲醇燃料电池(DMFC)拥有高的能量转换效率,燃料廉价易得,环境污染少,操作简便等优点,使得其在小型的可移动电源和微型电源等方面具备不可想象的应用前景。然而,如何提高阳极催化剂的电催化性能是DMFC发展的一个挑战。当前,铂(Pt)催化剂是研究最多的一种DMFC阳极催化剂。但是,此种Pt催化剂存在一个非常致命的缺陷:在甲醇的电催化氧化过程当中,Pt催化剂的电催化氧化的活性以及稳定性均比较低。选取合适的催化剂载体是制备出高性能Pt催化剂的最重要途径。本论文发明了一种新型的Pt催化剂载体,并考察了其对Pt催化剂性能提高的影响。本文第一次用聚苯胺(PANI)修饰混合催化剂载体二氧化钛-炭黑(Ti O2-C)以进一步提高Pt/二氧化钛-炭黑(Pt/Ti O2-C)对甲醇的电催化氧化的活性以及稳定性。首先,我们采用原位聚合法,用过硫酸铵(APS)作为氧化剂、硫酸(H2SO4)作为掺杂剂使苯胺(An)单体聚合反应合成聚苯胺(PANI);然后通过浸渍-还原法,用甲酸(HCOOH)来还原氯铂酸(H2Pt Cl6·6H2O),使Pt纳米颗粒沉积在混合催化剂载体Ti O2-C上。循环伏安曲线(CV)和计时电流曲线表征了所制备的催化剂对于甲醇的电催化氧化的活性以及稳定性,结果表明,与Pt/Ti O2-C催化剂相比,Pt-PANI/Ti O2-C催化剂对于甲醇具有更高的电催化氧化的活性以及稳定性。红外光谱(FT-IR)、X-射线衍射(XRD)、能谱(EDS)以及透射电子显微镜(TEM)等测试方法对催化剂进行了物理表征,证实了PANI的存在能够显著地提高Pt纳米颗粒的分散性,使其具有更窄的粒径分布。X射线光电子能谱(XPS)表明了Pt纳米颗粒与PANI之间确实有电子效应的存在,此电子效应的存在使得Pt-PANI/Ti O2-C催化剂对于甲醇的电催化氧化具有更高的稳定性。与此同时,本文还优化了Pt-PANI/Ti O2-C催化剂的制备工艺,当Ti O2在混合催化剂载体Ti O2-C中的含量为40%,An的用量为30%,An与APS的摩尔比nAn:nAPS为1:1,H2SO4的浓度为1.0 mol L-1时,Pt-PANI/Ti O2-C催化剂对甲醇具备最好的电催化氧化的活性以及稳定性。此外,本文还对比研究了Pt-PANI/Ti O2催化剂和Pt-PANI/C催化剂对于甲醇的电催化氧化的活性以及稳定性,结果表明,当用Ti O2作为催化剂的载体时所制备的Pt-PANI/Ti O2催化剂,其对甲醇的电催化氧化的活性低于用C作为催化剂的载体时所制备出的Pt-PANI/C催化剂,但其稳定性却高于Pt-PANI/C催化剂。
[Abstract]:Direct methanol fuel cell (DMFC) has the advantages of high energy conversion efficiency, cheap fuel, low environmental pollution, easy operation and so on, which makes it have unimaginable application prospect in small movable power supply and micro power supply. How to improve the electrocatalytic performance of the anode catalyst is a challenge for the development of DMFC. At present, the platinum Ptcatalyst is one of the most studied DMFC anode catalysts. This kind of Pt catalyst has a very fatal defect: the activity and stability of Pt catalyst are low during the electrocatalytic oxidation of methanol. This paper presents a new type of Pt catalyst carrier. The effect on the performance of Pt catalyst was also investigated. In this paper, the electrocatalytic oxygen of methanol was further improved by using Polyaniline (pani) modified mixed catalyst carrier titania-carbon black TIO _ 2-C) to further improve the catalytic activity of Pt/ titanium dioxide / carbon black Pt- TIO _ 2-C for methanol. Chemical activity and stability. First, Polyaniline was synthesized by in situ polymerization with ammonium persulfate (APS) as oxidant and aniline anion (aniline) monomer as dopant, and then the Polyaniline was synthesized by impregnation-reduction method. HCOOH) was used to reduce H _ 2Pt Cl6 _ 6H _ 2O, Pt nanoparticles were deposited on TIO _ 2-C mixed catalyst carrier. Cyclic voltammetry curves and chronoelectric current curves were used to characterize the activity and stability of the catalysts for methanol oxidation. The results show that. Compared with Pt/Ti O2-C catalyst, Pt-PANIR / TiO2-C catalyst has higher activity and stability for methanol oxidation. The catalyst was characterized by FTIR, EDS-X ray diffraction and transmission electron microscopy (TEM), etc. The results show that the catalytic activity of Pt-PANIR / TiO2-C catalyst is better than that of Pt-PANIR / TiO2-C catalyst, and the catalytic activity is better than that of Pt-PANIR / TiO2-C catalyst. It is proved that the existence of PANI can significantly improve the dispersion of Pt nanoparticles and make them have a narrower particle size distribution. X-ray photoelectron spectroscopy (XPS) shows that there is an electron effect between Pt nanoparticles and PANI. The existence of this electron effect makes the Pt-PANI/Ti O 2-C catalyst more stable for the electrocatalytic oxidation of methanol. At the same time, the preparation process of Pt-PANI/Ti O 2-C catalyst is optimized. When the content of TIO _ 2 in TIO _ 2-C is 40 and the amount of an is 30, the molar ratio of an to APS is 1: 1, H _ 2SO _ 4 is 1.0 mol L ~ (-1), the Pt-PANI- / TIO _ 2-C catalyst has the best electrocatalytic activity and stability for methanol oxidation. The activity and stability of Pt-PANI/Ti O 2 catalyst and Pt-PANI/C catalyst for methanol oxidation were compared. The results showed that the Pt-PANI/Ti O 2 catalyst was prepared when TIO 2 was used as the support of the catalyst. The activity of electrocatalytic oxidation of methanol was lower than that of Pt-PANI/C catalyst prepared with C as catalyst, but its stability was higher than that of Pt-PANI/C catalyst.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O643.36;TM911.4

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