Acta Chimica Sinica ›› 2012, Vol. 70 ›› Issue (22): 2359-2364.DOI: 10.6023/A12050234 Previous Articles     Next Articles



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
  • 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).

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