钌镧氧化物涂层析氯反应动力学比较研究

Comparative Study on Kinetics of Chlorine Evolution Reaction for Ru-La-O Oxide Coatings

通过热分解法制备了Ti/Ru O2和Ti/Ru-La-O氧化物涂层,利用微分电容和极化曲线等实验方法对涂层Clˉ特性吸附、La对Ru O2涂层析氯反应过程的影响及反应机理进行了研究。结果表明,在Na Cl溶液中,涂层表面存在Clˉ的特性吸附,这种特性吸附对析氯反应的动力学产生了影响,导致Tafel斜率上升,反应级数下降,加入La使氧化钌涂层的过电位下降,交换电流密度增大,有利于析氯反应的进行。本文对涂层存在的两种可能反应机理进行了比较分析,认为在中性Na Cl溶液中析氯反应是由2≡S·OCl*→rds2≡S·O+Cl2过程控制的。

The Ti/RuO2 and Ti/Ru-La-O oxide coatings were prepared by thermal decomposition of the metal chlorides in the precursor solution. The specific adsorption of Clˉ on coatings, the effect of La on the chlorine evolution reactions（Cl ER） and the kinetic mechanism were investigated by using differential capacity（DC） and polarization curves（PC）. Results show that the coating surface exhibits significantly specific adsorption of Clˉ in Na Cl neutral solution, which has an influence on the kinetics of the chlorine evolution process, resulting in an increase of the Tafel slope and a decrease of the reaction order. The addition of lanthanum reduces the overpotential of Ti/RuO2 coating and enhances the exchange current density, which improves the chlorine evolution reaction of the coatings. Both kinetic mechanisms of recombination and electrochemical desorption of adsorbed intermediate species for the coatings are comparatively studied. It is confirmed that the Chlorine evolution reaction on Ru-La-O oxide coatings in Na Cl neutral solution is controlled by the process of 2≡S·OCl＊→rds2≡S·O＋Cl2.