物理化学学报 >> 1998, Vol. 14 >> Issue (10): 919-926.doi: 10.3866/PKU.WHXB19981011

研究论文 上一篇    下一篇

铂单晶电极表面下不可逆反应动力学(III)

杨毅芸, 孙世刚   

  1. 厦门大学化学系,固体表面物理化学国家重点实验室,物理化学研究所,厦门 361005
  • 收稿日期:1998-01-21 修回日期:1998-05-11 发布日期:1998-10-15

Kinetics of Irreversible Reactions on Platinum Single Crystal Electrodes(III)

Yang Yi-Yun, Sun Shi-Gang   

  1. Department of Chemistry,State Key Laboratory for Physical Chemistry of Solid Surfaces,Institute of Physical Chemistry,Xiamen University,Xiamen 361005
  • Received:1998-01-21 Revised:1998-05-11 Published:1998-10-15

摘要:

在本系列研究论文Ⅰ[1]和Ⅱ[2]报导的结果基础上,进一步发展动力学数据解析方法.通过改变反应体系的温度,首次获得甲酸在Pt(100),Pt(110),Pt(111)电极上直接氧化反应的表观活化Gibbs自由能(△G≠0).在实验选定的标准状态下,即0.0V/SCE、298.15K和1.013×105Pa下,来算得到△G≠0Pt(100)=32.2±0.5kJ•mol-1, △G≠0Pt(111)=25.8±0.4kJ•mol-1, △G≠0Pt(110)=10.1±0.2kJ•mol-1. 还发现传递系数β在实验温度范围(283.15~303.15K)不随温度变化,但随电极表面原子排列结构变化,大小次序与△G≠0的变化一致.

关键词: Pt(100), Pt(111), Pt(110), 单晶电极, 甲酸直接氧化, 表观活化Gibbs自由能

Abstract:

Based on results of the lst and 2nd papers of the present studies, the procedure of data processing was developed further. Through the variation of the temperature of the reaction system the apparent Gibbs free energy of activation (△G≠0) for direct oxidation of HCOOH on Pt(100),Pt(111) and Pt(110) single crystal electrodes was obtained for the first time. Under the standard states defined in the present study i.e, at 0.0V/SCE.298.15K and 1.013×105Pa, the apparent Gibbs free energy of activatiou for HCOOH oxidation has been evaluated as 32.2±0.5 kJ.mol-1 on Pt(100), 25.8±0.4 kJ•mol-1 on Pt(111) and 10.1±0.2 kJ•mol-1 on Pt(110), respectively. It has been found that the transfer coefficient (β) of HCOOH oxidation is independent of temperature in the range between 283.15~303.15K, but varies with the surface atomic arrangement of Pt single crystal electrode and yields the same variation order as that of the apparent Gibbs free energy of activation.

Key words: Pt(100), Pt(111), Pt(110), Single erystal electrodes, Direct oxidation of HCOOH, Apparent Gibbs free energy of activation