化学学报 ›› 2017, Vol. 75 ›› Issue (2): 237-240.DOI: 10.6023/A16090460 上一篇    下一篇

所属专题: 先进电池材料

研究论文

Pt-Ni-P/Ti蜂窝状电极的制备及其催化甲醇氧化性能研究

陶熊新, 李莉, 齐学强, 魏子栋   

  1. 重庆大学化学化工学院 重庆 400044
  • 收稿日期:2016-09-01 修回日期:2016-12-19 出版日期:2017-02-15 发布日期:2016-12-20
  • 通讯作者: 魏子栋,E-mail:zdwei@cqu.edu.cn;Tel:023-65105161 E-mail:zdwei@cqu.edu.cn
  • 基金资助:

    项目受国家自然科学基金(Nos.21376283,21376284)资助.

Preparation and Electrochemical Properties of Honeycomb-like Pt-Ni-P/Ti Electrode for Methanol Oxidation

Tao Xiongxin, Li Li, Qi Xueqiang, Wei Zidong   

  1. College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044
  • Received:2016-09-01 Revised:2016-12-19 Online:2017-02-15 Published:2016-12-20
  • Contact: 10.6023/A16090460 E-mail:zdwei@cqu.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21376283 and 21376284).

Ti基体上,通过电沉积-置换的方法制备了具有蜂窝状结构的Pt-Ni-P/Ti催化电极.采用扫描电镜(SEM)、X射线衍射(XRD)对催化剂进行了表征.通过阳极线性伏安扫描法(LSV)、连续循环伏安法(CV)、预吸附单层CO溶出法研究了其甲醇氧化催化活性和抗CO中毒能力.SEM测试结果显示,非晶态Ni-P置换制备的Pt-Ni-P催化剂受“异地溶解-沉积”机理的影响而呈蜂窝状结构,而晶态Ni置换制备的Pt-Ni催化剂受“原位溶解-沉积”机理呈麦粒状.电化学测试结果表明,Pt-Ni-P/Ti电极在碱性介质中的甲醇氧化起始电位和CO氧化起始电位均比Pt-Ni/Ti电极更负,表明P掺杂可以增强Pt-Ni的甲醇氧化催化活性和抗CO中毒能力.

关键词: 直接甲醇燃料电池, 电沉积-置换, 电催化, 甲醇氧化

A honeycomb-like metallic catalyst (Pt-Ni-P/Ti) supported on a Ti sheet was prepared by electrodeposition-displacement method. The Ni-P amorphous alloy was first electrodeposited on the Ti substrate, and then replaced by displacement of Ni in amorphous Ni-P with H2PtCl6. The morphology and methanol oxidation performance of the prepared catalyst were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), anodic linear sweep voltammetry (LSV), cyclic voltammetry (CV), and the anodic stripping of a pre-adsorbed CO monolayer. The SEM results show that the Pt-Ni-P nanoparticles obtained by displacement of Ni in amorphous Ni-P with H2PtCl6 had a honeycomb-like porous structure, while the Pt-Ni nanoparticles had a wheat-like structure. The formation of the honeycomb-like porous structure can be explained by the so-called "out-situ dissolution-deposition mechanism", in which the metallic Ni in Ni-P/Ti electrode preferentially dissolve to form pore structure and release electron. The released electrons can be captured by the PtCl62- ion adsorbed on the surface of Ni-P and reduced on the surface of Ni-P to form Pt shell, thereby forming a honeycomb-like pore structure. For the Pt-Ni/Ti electrode, the formation of wheat-like structure Pt-Ni nanoparticles can be explained by a so-called "in-situ dissolution-deposition mechanism", in which the Pt replacement reaction can only occur at the surface of Ni, and the replacement Pt monolayer can prevent the further chemical substitution of Pt on Ni, thereby forming a wheat-like structure. The electrochemical test results show that the methanol oxidation and CO oxidation onset potential on Pt-Ni-P/Ti electrode in alkaline solution is more negative than that on Pt-Ni/Ti electrode, indicating that P incorporation can significantly enhance the methanol oxidation activity and CO-tolerance. Moreover, the unique honeycomb-like porous structure is beneficial to the fast mass transportation during the catalytic reaction. The combination of compositionally and geometrically favorable factors provides a new avenue to design new electrocatalysts with excellent methanol oxidation activity and CO-tolerance.

Key words: direct methanol fuel cell, electrodeposition-replacement, electrocatalysis, methanol oxidation