溴离子在铂电极上的电化学反应

ELECTROCHEMICAL REACTION OF BROMIDE IONS ON PLATINUMELECTRODE

用电位扫描和环盘电极等方法研究酸性介质中溴离子在铂电极上的多步氧化反应行为，证实在１．１Ｖ电位处发生的反应是：Ｂｒ－－ｅＢｒａｄ，（１）Ｂｒａｄ＋ＢｒａｄＢｒ２（ａｑ）．（２）在电位１．５Ｖ处发生的反应是：Ｂｒ２（ａｑ）Ｂｒａｄ＋Ｂｒａｄ，（２′）Ｂｒａｄ＋Ｈ２Ｏ－ｅ＝ＨＯＢｒ＋Ｈ＋．（３）其中反应（１）具有典型的可逆性．实验测得Ｂｒ－离子的扩散系数为１．８×１０－５ｃｍ２·ｓ－１，反应（１）的标准速率常数为２．０×１０－３ｃｍ·ｓ－１．

The electrochemical behaviour of bromide ions in sulphuric acid on a Pt electrode has been investigated by using potential sweep and rotating ring-disc electrode methods.The voltammograms show that bromide ions undergo a stepwise oxidation to hypobromous acid and the reactions areBr--eBrad,(1)Brad+BradBr2(aq). (2)at potential of 1.1V,andBr2(aq)Brad+Brad,(2′)Brad+H2O-e=HOBr+H+. (3)at potential of 1.5V respectively.The experimental results indicate that reaction (1) behaves reversibly.