物理化学学报 >> 1999, Vol. 15 >> Issue (11): 1023-1029.doi: 10.3866/PKU.WHXB19991113

研究论文 上一篇    下一篇

纳米钯膜电极的制备、结构表征和特殊反应性能

蔡丽蓉, 孙世刚, 夏盛清, 陈芳, 郑明森, 陈声培, 卢国强   

  1. 厦门大学固体表面物理化学国家重点实验室,化学系,物化所,厦门 361005
  • 收稿日期:1999-02-22 修回日期:1999-06-24 发布日期:1999-11-15
  • 通讯作者: 孙世刚

Particular Properties and Structure of Electrochemically Prepared Pd Film Nano-materials

Cai Li-Rong, Sun  Shi-Gang, Xia Sheng-Qing, Chen Fang, Zheng Ming-Sen, Chen Sheng-Pei, Lu Guo-Qiang   

  1. State Key Laboratory for Physical Chemistry of the Solid Surface,Department of Chemistry,Institute of Physical Chemistry,Xiamen University,Xiamen 361005
  • Received:1999-02-22 Revised:1999-06-24 Published:1999-11-15
  • Contact: Sun Shi-Gang

摘要:

用循环伏安方法制备纳米钯膜电极, 运用扫描隧道显微镜和原位红外光谱等方法研究其结构和反应性能. STM图像表明, 制备的纳米钯膜具有特殊的层状结构, 纳米级厚度的层状晶体由直径6nm左右的Pd微晶聚集而成. 发现当钯膜厚度为几个纳米时, CO的吸附表现出异常红外效应, 即红外谱峰反向和红外吸收显著增强(增强因子可达42.6). 纳米钯膜电极对氢的反应也具有特殊的性能, 与氢向钯晶格扩散吸收过程相比较, 氢吸脱附的表面过程成为主要反应. 研究结果还指出, 纳米钯膜电极的异常红外效应和对氢反应的特殊性能与钯膜厚度密切关联,并可归结为钯膜材料的纳米尺度效应.

关键词: 纳米钯膜电极, 异常红外效应, 氢吸脱附性能, STM, 原位FTIRS

Abstract:

The Pd film nano-materials supported on glassy carbon (nm Pd/GC) were prepared under conditions of electrochemical voltammetry. STM images illustrated that the Pd film consists of crystallites which are composed of nano-particles of Pd with average size at around 6nm,and are of layer shapes. CO adsorption on nm-Pd/GC electrodes manifested abnormal infrared effects (AIREs), i.e., the inversion of IR band direction and the enhancement of IR absorption. In comparison with CO adsorption on massive Pd electrode, an enhancement factor at 42.6 was measured on a nm-Pd/GC electrode of film thickness at 12.2nm.The nm-Pd/GC electrode possesses particular properties for hydrogen reaction. It was revealed that, in contrast to hydrogen absorption by massive Pd electrode, the surface processes of hydrogen adsorption desorption become the dominant reaction on nm-Pd/GC electrodes. The results demonstrated also that both the AIREs for CO adsorption and the particular properties for hydrogen reaction depend strongly on the thickness of Pd film, and can be consequently assigned to the nanometer size effect of Pd film materials. The present study has introduced important significance for further studies on surface electrochemistry and electrocatalysis. 

Key words: nm-Pd/GC electrode, Abnormal infrared effects(AIREs), Hydrogen adsorption-desorption, STM, in situ FTIRS