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

LONG Ping, XU Li-Kun, CUI Xiu-Fang, JIN Guo
2015 Journal of Inorganic Materials  
摘 要: 通过热分解法制备了 Ti/RuO 2 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 Cl特 性吸附、La 对 RuO 2 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 NaCl 溶液中, 涂层表面存 在 Cl¯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 NaCl 溶液中析氯反应是由 rds 2 2 S OCl* 2 S O Cl º ⋅   º ⋅ + 过程控制的。 关 键 词: 特性吸附; 钌镧氧化物; 析氯反应; Volmer-Tafel 机理; RuO 2 中图分类号: TQ174 文献标识码: A Abstract: The Ti/RuO 2 and Ti/Ru-La-O oxide coatings were prepared by thermal decomposition of the metal
more » ... rides in the precursor solution. The specific adsorption of Cl¯ on coatings, the effect of La on the chlorine evolution reactions (ClER) 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 Cl¯ in NaCl 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/RuO 2 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 NaCl neutral solution is controlled by the process of rds 2 Fig. 9 Relationship between Tafel slope and coverage  (a), and reaction order p and  (b) for Volmer-Tafel mechanism at g= -2, 0, 5 涂层作为对比, 通过微分电容和极化曲线等实验技 术研究了电极涂层表面的特性吸附、La 对析氯反应 的影响及析氯反应的机理, 认为在 NaCl 的中性溶液 中, 电极表面存在 Cl¯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 使电极的过电位下降, 交换 电流密度增大, 这有利于析氯反应的进行。根据实验 数据对 Volmer-Heyrovsky 和 Volmer-Tafel 机理的比 较分析, 可以认为, 发生该氧化物涂层的析氯反应 符合 Volmer-Tafel 机理过程。 参考文献:
doi:10.15541/jim20140425 fatcat:qbwi5t7fizc7vgpyjdilfxhr3a