化学学报 ›› 2012, Vol. 70 ›› Issue (22): 2359-2364.DOI: 10.6023/A12050234 上一篇    下一篇

研究论文

Cu@Pt/MWCNTs-MnO2电催化剂的制备及电催化性能研究

于书平, 娄群, 刘润婷, 韩克飞, 汪中明, 朱红   

  1. 北京化工大学化工资源有效利用国家重点实验室 北京 100029
  • 投稿日期:2012-10-16 发布日期:2012-10-31
  • 通讯作者: 朱红 E-mail:zhuho128@126.com
  • 基金资助:
    项目受国家自然科学基金(No. 21176022)、国际合作(No. 2009DFA63120)和国防科学研究(No. A1420110023)资助.

Synthesis and Electrocatalytic Performance of Cu@Pt/MWCNTs-MnO2 Electrocatalyst

Yu Shuping, Lou Qun, Liu Runting, Han Kefei, Wang Zhongming, Zhu Hong   

  1. State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029
  • Received:2012-10-16 Published:2012-10-31
  • Supported by:
    Project supported by the National Natural Science Foundation of China (No. 21176022), the International S&T Cooperation Program of China (No. 2009DFA63120), and the National Defense Basic Scientific Research Program of China (No. A1420110023).

通过浸渍还原法, 以乙二醇作为还原剂, 以H2PtCl6·6H2O作为Pt的前驱体制备了Cu@Pt/MWCNTs核壳型电催化剂; 通过水热法, 以KMnO4和Mn(NO3)2作为锰源制备了α-MnO2β-MnO2, 并把Cu@Pt/MWCNTs核壳型电催化剂与二氧化锰进行掺杂制得Cu@Pt/MWCNTs-MnO2复合材料. 利用XRD, SEM, TEM对复合材料的结构和形貌进行表征, 利用循环伏安测试曲线和阴极极化曲线等电化学测试方法对电催化剂的性能进行测试. 结果表明, 电催化剂中Cu@Pt纳米颗粒为核壳型, 粒径为6~8 nm, MnO2的晶型为α-MnO2β-MnO2; 另外, Cu@Pt/MWCNTs-MnO2复合材料具有良好的催化性能, 其中Cu@Pt/MWCNTs-β-MnO2电催化剂的电化学性能较好, 具有较大的电化学活性面积, 为71.1 m2·g-1, 同时对MnO2促进氧还原的机理进行了初步探讨.

关键词: 质子交换膜燃料电池, 核壳型, 二氧化锰, 电催化剂, 电化学活性面积

The core-shell structure catalysts with reduced Pt loading and improved catalytic activity which are inter-metallic Pt electrocatalyst with a cheap transition metal core have become a critical issue in fuel cells. In this study, Cu@Pt/MWCNTs core-shell electrocatalyst was prepared through the impregnation chemical reduction method, by using ethylene glycol as the reducing agent, H2PtCl6 as a precursor of Pt and CuSO4 as a precursor of Cu. At the appropriate temperature and pH (adjusted by KOH/EG solution), Cu nanoparticles were reduced on the surface of MWCNTs (140 ℃, pH=10), and then Pt atoms were deposited on the surface of Cu nanoparticles (90 ℃, pH=7~8). α-MnO2 and β-MnO2 were prepared by hydrothermal method with KMnO4 and Mn(NO3)2 as the manganese source, the reaction time of α-MnO2 and β-MnO2 is 8 h and 72 h, respectively. The obtained manganese dioxide was doped onto Cu@Pt/MWCNT under ultrasound to make Cu@Pt/MWCNTs-MnO2 composite catalysts. The structure and morphology of Cu@Pt/MWCNTs and MnO2 were characterized by XRD, SEM and TEM, electrochemical performances were investigated by cyclic voltammetry, cathodic polarization and other electrochemical methods. In order to discuss the oxygen reduction method of Cu@Pt/MWCNTs-MnO2, RRDE (rotating ring-disk electrode) was further used to examine the catalytic oxygen reduction reactions of Cu@Pt/MWCNTs-MnO2. Our results demonstrated that the Cu@Pt nanoparticles have the core-shell structure. The diameter of the nanoparticles is about 6~8 nm. The crystal morphology of MnO2 is α-MnO2 and β-MnO2. It was also found that the Cu@Pt/MWCNTs-β-MnO2 composite catalysts have better catalytic performance and higher electrochemical activity surface (up to 71.1 m2·g-1). The RRDE results for the ORR indicate that, the main reaction of Cu@Pt/MWCNTs-β-MnO2 catalyst is the direct reduction of O2 to H2O which is same as the mechanism of Cu@Pt/MWCNTs catalyst, both with a four-electron charge transfer. Moreover, the mechanism of MnO2-promoting effects for the oxygen reduction was also discussed in this paper.

Key words: PEMFC core-shell, manganese dioxide, electrocatalyst, oxygen reduction, electrochemical active surface