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电化学(中英文) ›› 1996, Vol. 2 ›› Issue (1): 23-23. 

• 研究论文 • 上一篇    下一篇

酸性溶液中Rh电极上CO孪生吸附态的FTIRS研究

林文锋,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
  • 收稿日期:1996-02-28 修回日期:1996-02-28 出版日期:1996-02-28 发布日期:1996-02-28

FTIS Observation of Twin Adsorbates of CO on Rh Electrode in Acid Solution

Lin Wenfeng; Sun Shigang   

  1. (State Key Laboratory for Physical Chemistry of the Soliu Sur face,Department of Chemistry, Xiamen University, Xiamen 361005
  • Received:1996-02-28 Revised:1996-02-28 Published:1996-02-28 Online:1996-02-28

摘要: 采用现场多步FTIR光谱技术结合CO吸附分子探针方法,研究了Rh电极表面分子过程。在电化学处理后的光滑Rh电极表面上首次检测到两种CO孪生吸附态及其随电位变化过程。使用电位循环扫描方法改变Rh电极表面状态,在0.05mol/LH2SO4酸性溶液中,选取-0.275至2.4V电位区间和1.5V/s扫描速率对Rh电极进行循环扫描处理2min,处理后的Rh电极表面积累一层氧化物,CO以孪生态吸附于表面Rh氧化物上,在2166和2112cm-1处给出一对宽的IR吸收峰;在负电位下,表面氧化物被还原生成表面Rh原子簇,CO仍以孪生态吸附于表面Rh原子簇上,在2102和2032cm-1处给出一对尖的IR吸收峰;表面Rh原子簇不稳定,随着电位正移分解和扩散形成平滑的Rh表面,此时CO则以线式和桥式吸附于平滑的Rh表面,分别在2048和1919cm-1处给出两个IR吸收峰。

关键词: 现场多步FTIR光谱, 表面过程, 孪生吸附态, 一氧化碳

Abstract: Because of its great importance both in electrocatalysis and C1 chemistry applications, the adsorption of CO on metallic electrodes such as Pt, Pd, Au, Ag, RhF ̄[1~2], etc. has been extensively studied by in situ infrared spectroscopy Since 1981. In all these studies only three types of CO adsorbates, i. e. , linear (2 090~2 000 cm ̄(-1)), bridgrd (2 000~1 900 cm ̄(-1)) or multi-bonded (1900~1 800 cm ̄(-1)) species, were identified. A different absorbate, twin CO on rhodium ((Rh (CO)2) , does exist on the solid/gas interface of highly dispersed Rh or Rhn clusters[3~4] on supports,this species originating a doublet at 2100 and 2030 cm ̄(-1) for its symmetrical and asymmetrical stretch modes, respectively. To our knowledge, this doublet has not been reported yet for the Rh/electrolyre interface.

Key words: In situ multi-step FTIRS, Surface processes, Twin adsorbates, Carbon References

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