欠电位沉积研究进展

Underpotential Deposition

欠电位沉积(underpotential deposition,UPD)是指一种金属可在比其热力学可逆电位正的电位下沉积在另一基体上的现象,是一个与电极/溶液结构密切相关的重要的电化学现象。从广义上讲,定义中的沉积元素与基体不仅仅局限于金属元素,还包括非金属元素、纳米粒子等其它物质。由于单原子厚度的异种金属能显著改变界面附近的电势分布和影响溶剂分子的取向,并改变基底金属表面的吸附行为和反应能力,使得UPD在电催化和金属与合金电沉积研究中颇受重视。迄今为止,已报道了大量UPD实验现象。本文在现有文献基础上,总结了UPD的若干理论模型及其行为特征,着重探讨了衬底、离子吸附、温度等因素对UPD过程的影响作用,介绍了UPD应用的主要成功实例,并对其研究前景提出了展望。

Underpotential deposition （UPD）, the phenomenon of metal monolayer（s） formation on a foreign metal substrate at a potential more positive than the equilibrium potential for bulk electro-deposition, has been the subject of considerable research in recent years because it yields model systems for investigation of the electrode/electrolyte interface. Broadly speaking, the defined sedimentary elements or substrates of UPD are not limited to metal elements, and also include other substances such as nonmetallic elements, nano-particles, and so forth. In virtue of the great potential that monolayer film of dissimilar metals can significantly change the potential distribution near the interface, the orientation of the solvent molecules and the adsorption behaviors and reaction ability of the base metal surface, UPD draws great academic attention to its applications in electro-catalysis as well as electro-deposition of metal and alloy. A large number of experimental reports about UPD have been published so far. Based on literature in existence, several theoretical models and the behavior characteristics of UPD were summarized. Moreover, some factors such as substrates, ionic adsorption and temperature on the UPD process were emphasized. Finally, its practical applications were highlighted and the future research directions were pointed out.