温度对PbO2电沉积形核生长过程的影响研究

为了探讨温度对PbO₂电沉积形核生长过程的影响，在25℃、35℃、45℃、55℃、65℃使用电化学工作站测试了PbO₂在玻碳电极上沉积过程的循环伏安曲线、计时电位曲线及计时电流曲线，并对不同温度下电沉积的PbO₂镀层进行了SEM和XRD分析. 结果表明，在不同温度下PbO₂都经历了成核和核生长过程. 温度的升高没有改变PbO₂电沉积三维连续成核的模式，降低了沉积过程溶液阻力，对成核和晶体生长速率均有促进作用，在晶核密度达到饱和晶核密度以前，是以促进成核速率为主，减小PbO₂颗粒尺寸. 达到饱和晶核密度后，电沉积后期以促进晶体生长速率为主，不利于形成细小PbO₂颗粒.高温使得析氧速率提高，能耗增大.由实验结果得出，在55℃时得到的PbO₂镀层粒径最小.

Effects of Temperature on the Nucleation and Growth Mechanism of PbO2 Electrodeposition

In order to investigate the effects of temperature on the nucleation and growth of lead dioxide (PbO₂)， the in situ electrochemical depositions of PbO₂ were carried out on the glassy carbon electrode at different temperatures, namely, 25℃,35℃, 45℃, 55℃, and 65℃.The cyclic voltammetric curves, the time-current and the time-potential curves，SEM images and XRD patterns of the PbO₂ coatings deposited at different temperatures were obtained. The results showed that the PbO₂ underwent nucleation and grew at different temperatures. The 3D continuous nucleation mode of PbO₂ electrodeposition remained unchanged with the increase of temperature. However, the solution resistance during the deposition process was decreased. The nucleation rate and the crystal growth rate were both promoted by the increase of temperature. Before reaching the saturated nucleation density, the nucleation rate was accelerated，and the size of PbO₂ particles was reduced. During the later stage of the deposition, once the saturated nucleation density was attained, the nucleation rate became prodimnant, which adversely influenced the crystal growth rate，and the coating was not conductive to the formation of small PbO₂ particles. High temperature enhanced the oxygen evolution rate and increased the energy consumption. The average particle size of PbO₂ obtained at 55 ℃ was the smallest one among the five temperatures tested.