高等学校化学学报

高等学校化学学报 ›› 2000, Vol. 21 ›› Issue (8): 1288.

• 论文 • 上一篇    下一篇

碱性介质中甘氨酸在Pt电极上解离吸附和氧化反应的原位红外反射光谱研究

肖晓银, 孙世刚, 吴启辉, 周志有, 陈声培   

  1. 厦门大学固体表面物理化学国家重点实验室, 化学系, 物理化学研究所, 厦门 361005
  • 收稿日期:1999-08-26 出版日期:2000-08-24 发布日期:2000-08-24
  • 通讯作者: 孙世刚(1954年出生),男,博士,教授,博士生导师,从事表面电化学与电催化研究.
  • 基金资助:

    国家自然科学基金(批准号:29833060)

In situ FTIR Spectroscopic Investigations of Dissociative Adsorption and Electrooxidation of Glycine at the Pt Electrode in Alkaline Solutions

XIAO Xiao-Yin, SUN Shi-Gang, WU Qi-Hui, ZHOU Zhi-You, CHEN Sheng-Pei   

  1. State Key Laboratory for Physical Chemistry of Solid Surfaces, Department of Chemistry, Institute of Physical Chemistry, Xiamen University, Xiamen 361005, China
  • Received:1999-08-26 Online:2000-08-24 Published:2000-08-24

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被引次数

10

摘要： 运用原位红外反射光谱研究了碱性介质中甘氨酸在Pt电极上的解离吸附和氧化反应行为,并利用纳米Pt膜电极的异常红外效应鉴定反应过程中生成的表面吸附物种.结果表明:甘氨酸在Pt电极上极易发生解离,生成强吸附于电极表面上的氰基负离子,该吸附物种在低于0V电位下能稳定存在,并抑制甘氨酸的进一步反应.当电位高于0.2V时,氰基负离子被氧化为氰酸根离子进入溶液,使甘氨酸发生氧化反应,生成氰酸盐和碳酸盐等产物.

关键词: 甘氨酸, 解离吸附, 电氧化, Pt电极, 原位红外反射光谱

Abstract: The dissociative adsorption and electrooxidation of glycine on Pt electrode in 0.1 mol/L NaOHsolutions were studied using cyclic voltammetry and in situ FTIRspectroscopy. The results demonstrated that a strong interaction exists between glycine and Pt surface, leading to dissociate easily glycine on Pt surface at potentials below 0.2 Vto form cyanide and carboxylate ions. The strongly adsorbed cyanide species on the electrode surface can inhibit the oxidation of glycine, and are considered as poison species for the reaction. The oxidation of glycine at potentials above 0.2 Vyielded solution species of cyanate and carboxylate. The cyanide species derived from dissociative adsorption of glycine can be isolated on electrodes of smooth Pt and nanometer thin Pt film supported on glassy carbon(nm-Pt/GC), and has been determined by in situ FTIRSas showing a band at around 2100 cm-1 . The intensity of IRabsorption band of cyanide on nm-Pt/GCsurface is 14 times larger than that on a smooth Pt surface, and the IRband is in the opposite direction to that obtained on Pt surface, confirming the adsorption of cyanide species and the abnormal IReffects. The IRabsorption of cyanate and carboxylate produced in the oxidation of glycine yields infrared bands at around 2169 and 1390 cm-1 , respectively. The present study revealed the interaction between glycine and Pt electrode surface, and suggested the adsorption modes and oxidation mechanism of glycine on Pt electrode as well.

Key words: Glycine, Dissociative adsorption, Electrooxidation, Pt electrode, In situ FTIR spectra

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