化学学报 ›› 2013, Vol. 71 ›› Issue (02): 227-233.DOI: 10.6023/A12080553 上一篇    下一篇

研究论文

电化学合成PtCo/石墨烯复合催化剂及对甲醇的电催化氧化

史国玉a,b, 王宗花a,b, 夏建飞a,b, 张菲菲a,b, 夏延致a,b, 李延辉a   

  1. a 青岛大学 纤维新材料与现代纺织实验室 国家重点实验室培育基地 青岛 266071;
    b 青岛大学 化学化工与环境学院 青岛 266071
  • 收稿日期:2012-08-14 出版日期:2013-02-14 发布日期:2013-01-09
  • 通讯作者: 王宗花, 夏延致 E-mail:wangzonghua@qdu.edu.cn; qduxyzh@163.com
  • 基金资助:

    项目受国家自然科学基金(Nos. 20975056, 81102411, 21275082);山东省自然科学基金(Nos. ZR2011BZ004, ZR2011BQ005);NSFC-JSPS中日合作与交流项目(No. 21111140014);生命分析化学国家重点实验室开放基金(No. SKLACLS1110)和973计划的资助(No. 2012CB722705)资助.

Electrochemical Deposition of Graphene Supported PtCo Composite Catalysts for Electrocatalytic Methanol Oxidation

Shi Guoyua,b, Wang Zonghuaa,b, Xia Jianfeia,b, Zhang Feifeia,b, Xia Yanzhia,b, Li Yanhuia   

  1. a Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao 266071;
    b College of Chemical and Environment Engineering, Qingdao University, Qingdao 266071
  • Received:2012-08-14 Online:2013-02-14 Published:2013-01-09
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 20975056, 81102411, 21275082), Natural Science Foundation of Shandong (Nos. ZR2011BZ004, ZR2011BQ005), Japan Society for the Promotion of Science and National Natural Science Foundation of China under the Japan-China Scientific Cooperation Program (No. 21111140014), State Key Laboratory of Analytical Chemistry for Life Science (No. SKLACLS1110) and the National Key Basic Research Development Program of China (973 special preliminary study plan, Grant no.: 2012CB722705).

以ITO导电玻璃为基体, 采用恒电位沉积法制备了PtCo/石墨烯(GN)复合催化剂. 通过扫描电镜(SEM), X射线能量散射谱(EDX)及电化学方法对催化剂进行了表征. SEM结果表明, 石墨烯能够促进催化剂粒子的均匀分布, 降低催化剂粒径; 当Pt和Co物质的量之比为1:2.93时, 该催化剂粒径最小, 分布最为均匀. 电化学测试结果表明, 石墨烯作为载体能够提高催化剂抗CO中毒性能, 有利于对甲醇的催化氧化, 这主要是由石墨烯优异的电子导电性和表面含氧活性基团所决定的. 而且由于Co特殊的电子效应, 它的加入也能够影响该催化剂的催化活性. 结果证明, 当Pt和Co物质的量之比为1:2.93时, 该复合催化剂表现出对甲醇氧化最为优越的催化性能, 甲醇氧化峰电流密度可达到662 A·gpt-1, 正反扫电流(If/Ib)比为2.34, 是传统PtCo/C催化剂(If/Ib=1.32)的近1.8倍.

关键词: 石墨烯, 甲醇氧化, PtCo复合催化剂, 电沉积, 抗CO中毒

Direct methanol fuel cells are excellent power sources due to their high energy density, low pollutant emission and easy handling. However, commercial applications are limited by the high cost related to noble metal catalysts. Recent findings have proved that appropriate catalyst support, which improves the utilization of the noble metals in great depth, may be one breakthrough. Graphene nanosheet (GNS), a new two-dimensional carbon material with a single (or a few) atomic thickness, as the combination of its high surface area, high conductivity and unique graphitized basal plane structure, has recently attracted an enormous amount of interest from both theoretical and experimental scientists. It has been proved that catalysts supported on GNSs show improved activity than those supported on carbon black. Furthermore, alloying Pt with other metal is widely approved as a practical method to relieve the CO-poisoning of the catalyst, which can be ascribed to both a bi-functional mechanism and a ligand (electronic) effect. In this experiment, PtCo/graphene (GN) composite catalysts were synthesized on an indium tin oxide (ITO) substrate by the potentiostatic method. Catalyst samples were characterized by scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDX) and electrochemical methods. SEM results showed that the addition of graphene could enhance the dispersion of the catalytic particles and reduce the particle size, especially when the molar ratio of Pt and Co is 1:2.93, the particles had the smallest size and the best dispersion. Electrochemical tests demonstrated that graphene as the catalytic support could improve the CO-tolerance of the catalysts, which was determined by the outstanding electric conductivity and rich oxygen-containing species of graphene, resulting in good performance for electrocatalytic methanol oxidation. Furthermore, owing to the special electronic effect of Co, its addition also influenced the catalytic activity. It was found that when the molar ratio of Pt and Co was 1:2.93, the composite catalyst exhibited the most excellent catalytic performance for electrocatalytic methanol oxidation with the forward anodic peak current density of 662 A·gpt-1and the If/Ib of 2.34 which was nearly 1.8 times that of the traditional PtCo/C catalyst (If/Ib=1.32).

Key words: graphene, methanol oxidation, PtCo composite catalyst, electrodeposition, CO-tolerance