阴离子膜燃料电池中Fe、Ni基氧还原催化剂的制备及性能

发布时间：2018-02-04 23:49

  本文关键词： 阴离子膜燃料电池 非贵金属阴极催化剂 氧还原反应　出处：《大连海事大学》2016年硕士论文　论文类型：学位论文

【摘要】：以碱性阴离子膜为电解质的阴离子膜燃料电池(AEMFC)不仅能提高氧还原反应(oxygen reduction reaction,ORR)动力学,而且可以使用非贵金属阴极催化剂,从而大大降低制造成本,在燃料电池的商业化进程中更具有竞争力。作为关键部件之一的ORR催化剂,其性能优劣直接关系电池输出性能的好坏,开发新型、低成本的ORR催化剂,对推动AEMFC的发展具有重要的理论和实际意义。本文以淀粉为碳源,纳米氧化铁和氧化镍为活性中心,通过高热解法制备了Fe/C、Ni/C、FeNi/C催化剂。高分辨率的透射电镜证实,三种催化剂均具有核壳结构,壳为片层石墨层,核为金属纳米颗粒。Fe纳米颗粒的粒径约为25 nm,而Ni颗粒与合金颗粒直径分别为几十纳米到几百纳米不等,三种催化剂均对02表现出催化活性。当热解温度为800℃、保温时间4 h时,控制淀粉与铁、镍的质量比分别为:100:5(淀粉/铁)、50:1(淀粉/镍)和100:2:3(淀粉/铁/镍)可分别制备出具有最优催化活性的Fe/C、Ni/C、FeNi/C催化剂。催化剂的最大比表面积为:373 m2·g-1。在最优条件下制备的三种催化剂在-0.6V时氧还原反应的极化电流密度分别达到0.799 mA,cm-2、0.89 mA·cm-2、1.266 mA·cm-2,对ORR的催化活性顺序为:FeNi/CNi/CFe/C。与Fe/C与Ni/C相比,FeNi/C的ORR催化活性分别提高了58.4%、42.2%。在三种催化剂上,ORR的电子转移数分别为:2.29、2.83、3.26,表明氧还原反应同时存在2电子和4电子过程。三种催化剂经过500次的循环伏安测试后,性能未出现衰减,均表现出良好的稳定性。
[Abstract]:The anion membrane fuel cell with alkaline anion membrane as electrolyte can not only increase oxygen reduction reaction, but also improve oxygen reduction reaction. ORR) kinetics, and the use of non-noble metal cathode catalysts can greatly reduce manufacturing costs and become more competitive in the commercialization process of fuel cells. As one of the key components, ORR catalyst. Its performance is directly related to the output performance of the battery. The development of new low-cost ORR catalyst has important theoretical and practical significance to promote the development of AEMFC. In this paper, starch is used as carbon source. Fe / C / Ni / Ni / Fe / Ni / C catalysts were prepared by high pyrolysis of nano-ferric oxide and nickel oxide as active centers. The results of high resolution transmission electron microscopy show that the three catalysts have core-shell structure. The shell is a lamellar graphite layer, the core is metal nanoparticles. Fe nanoparticles are about 25 nm in diameter, while Ni particles and alloy particles have diameters ranging from tens to hundreds of nanometers. When the pyrolysis temperature is 800 鈩，

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