三乙醇胺在金属电沉积中的基本效应  

The Fundamental Effects of Triethanolamine in the Electrodeposition of Metals

作　　者：蔡加勒[1] 周绍民[1] 

机构地区：[1]厦门大学化学系

出　　处：《高等学校化学学报》1994年第1期79-84,共6页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金

摘　　要：用微分电容法、极谱法、原位表面增强拉曼光谱法和微盘电极法研究了碱性溶液中存在和不存在Ｚｎ^（２＋）、Ｃｄ^（２＋）、Ｃｕ^（２＋）、Ｎｉ^（２＋）、Ｆｅ^（３＋）和Ｓｎ^（４＋）等离子时三乙醇胺（ＴＥＬＡ）在电极／溶液界面上的电化学行为。结果表明，ＴＥＬＡ以平卧方式吸附，符合Ｆｒｕｍｋｉｎ吸附等温线。在碱性溶液中ＴＥＬＡ与Ｚｎ^（２＋）、Ｃｄ^（２＋）、Ｃｕ^（２＋）、Ｎｉ^（２＋）和Ｆｅ^（３＋）等离子生成具有表面活性的混合配体配合物，其吸附性较ＴＥＬＡ的强。ＴＥＬＡ不同程度地影响上述金属离子的电还原过程，根据实验结果提出ＴＥＬＡ对锌电沉积的阻化作用机制及其基本效应。The behaviour of triethanolamine(TELA) at electrode/solution interface in alkaline solution with and without Zn2+、Cd2+、Cu2+、Fe3+ and Sn4+ ions has been studied by means of differential capacity,polarography,in-situ surface-enhanced Raman spectroscopy(SERS)and microdisc electrodes.The influence of TELA on the discharging process of above ions and the inhibition of TELA on the electrodeposition of zinc have been studied.The results are summarized as follows:TELA has a stronger adsorptivity at the Hg(or Ag)/solution interface and adsorbs with·lat' orientation on Ag electrode at the potential of maximum adsorption(～-0. 60 V).TELA adsorption on Hg electrode obeys the Frumkin isotherm and possesses a linear relationship between(Ep-Em)2 and lgCTELA.Mixed ligand coordination compounds of metallic ions(such as Zn2+,Cd2+,Cu2+,Ni2+ and Fe3+) with TELA and OH- ions are formed,and these coordination compounds are surface-active. Their adsoption activities on Hg electrode are Ni(Ⅱ)>Fe(Ⅲ),Cu(Ⅱ)>Zn(Ⅱ)>Cd(Ⅱ).TELA affects the electroreduction of t he above metallic ions in different degree.The influences of TELA are the same in the sequence as adsoption activities corresponding to mixed ligand coordination compounds,The free energy of TELA adsorption in the presence of zinc ion has a more negative value than that in the absence of zinc ion.The interaction of adsorbed TELA molecular changes from weak repellant to weak attraction in the presence of zinc ion.The observed rate constants for zinc electrodepositon(at-1.400 V)reduce according to the increase of TELA concentration,and its inhibitive mechanism can be expressed by ks=k0(1-θ)+k1θ

关 键 词：三乙醇胺 吸附 金属电沉积 络合物 

分 类 号：O623.42[理学—有机化学]