物理化学学报 >> 2014, Vol. 30 >> Issue (2): 318-324.doi: 10.3866/PKU.WHXB201312121

电化学和新能源 上一篇    下一篇

Fe-N/C-TsOH催化剂应用碱性介质催化氧还原的电催化活性

徐莉1,2, 潘国顺1,2, 梁晓璐1,2, 罗桂海1,2, 邹春莉1,2, 罗海梅1,2   

  1. 1 清华大学摩擦学国家重点实验室, 北京100084;
    2 深圳清华大学研究院深圳市微纳制造重点实验室, 广东深圳518057
  • 收稿日期:2013-10-14 修回日期:2013-12-11 发布日期:2014-01-23
  • 通讯作者: 潘国顺 E-mail:pangs@tsinghua.edu.cn
  • 基金资助:

    国家自然科学基金(91223202),国家国际科技合作专项项目(2011DFA73410),清华大学自主科研计划(20101081907)及国家重点基础研究发展规划项目(973) (2011CB013102)资助

Electrocatalytic Activity of Fe-N/C-TsOH Catalyst for the Oxygen Reduction Reaction in Alkaline Media

XU Li1,2, PAN Guo-Shun1,2, LIANG Xiao-Lu1,2, LUO Gui-Hai1,2, ZOU Chun-Li1,2, LUO Hai-Mei1,2   

  1. 1 The State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, P. R. China;
    2 Shenzhen Key Laboratory of Micro/nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, Guangdong Province, P. R. China
  • Received:2013-10-14 Revised:2013-12-11 Published:2014-01-23
  • Contact: PAN Guo-Shun E-mail:pangs@tsinghua.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (91223202), International Science & Technology Cooperation Program of China (2011DFA73410), Tsinghua University Initiative Scientific Research Program, China (20101081907), and National Key Basic Research Program of China (973) (2011CB013102).

摘要:

通过溶剂分散热处理方法制备了一种吡咯和对甲苯磺酸(TsOH)共同修饰的碳载非贵金属复合催化剂(Fe-N/C-TsOH),并采用扫描电子显微镜(SEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)对催化剂的形貌和组成成分进行表征. 借助循环伏安法(CV)和旋转圆盘技术研究了TsOH对催化剂在0.1 mol·L-1 KOH介质中催化氧还原性能的影响. 结果表明:TsOH的存在对催化剂催化氧还原反应(ORR)的活性影响很大. 以其制备的气体扩散电极在碱性电解质溶液中催化氧还原过程时转移的电子数为3.899,远比不含TsOH修饰的催化剂催化氧还原的电子数(3.098)高. 此外,研究发现600 ℃热处理过的Fe-N/C-TsOH催化剂表现出最佳的氧还原催化性能. 相比未经热处理过的Fe-N/C-TsOH催化剂,起峰电位和-1.5 mA·cm-2电流密度对应的电压分别向正方向移动30 和170 mV. XPS研究结果表明吡咯氮是催化剂主要活性中心,提供氧还原活性位,而TsOH加入形成的C―Sn―C和―SOn―有利于催化剂催化氧还原活性的提高,从而使该催化剂对氧还原表现出很好的电催化性能和选择性.

关键词: 非贵金属催化剂, 双杂化, 热处理, 碱性燃料电池, 氧还原反应

Abstract:

Pyrolyzed carbon supported ferrum polypyrrole (Fe-N/C) catalysts were synthesized with and without the dopant p-toluenesulfonic acid (TsOH) through a solvent-grinding method followed by heattreatment at the desire temperature. Both the catalysts were characterized using electrochemical techniques, such as cyclic voltammetry (CV), as well as the rotating disk electrode (RDE) technique. It was found that the catalysts doped with TsOH showed significantly better oxygen reduction reaction (ORR) activity than the undoped catalysts. The average electron transfer numbers for the catalyzed ORR were 3.899 and 3.098 for the TsOH-doped and undoped catalysts, respectively. Thermal treatment was found to be a necessary step for catalyst activity improvement. The catalyst pyrolyzed at 600 ℃ showed the best ORR activity: the onset potential and the potential at the current density of -1.5 mA·cm-2 for the TsOHdoped catalyst were 30 and 170 mV more positive than those for the un-pyrolyzed TsOH-doped catalyst, respectively. To clarify the effects of TsOH doping and pyrolyzation, scanning electron microscopy (SEM), X- ray diffraction (XRD), and X- ray photoelectron spectroscopy (XPS) were used to analyze the morphology, structure, and composition of the catalysts. The XPS results suggest that the pyrrolic-N groups are the most active sites and sulfur species are structurally bound to carbon in the form of C―Sn―C and oxidized ―SOn― bonds, which is an additional beneficial factor for the ORR.

Key words: Non-noble metal catalyst, Dual-dopant, Heat-treatment, Alkaline fuel cell, Oxygen reduction reaction

MSC2000: 

  • O646