不同浸润性多孔电极表面的气泡行为

Behavior of Bubbles on Electrodes with Hierarchical Microporous Structures and Different Wettability

采用氢气模板法制备了具有多孔结构的电极;通过改变电镀电流密度和电镀时间实现了电极表面多孔结构孔径和分布的控制;通过改变表面化学组成有效调控了电极表面的浸润性质.比较了具有不同微观结构和表面化学组成的电极在给定条件下电解水过程中气泡的产生及行为机制.实验结果表明:相对于亲水的多孔电极,疏水的多孔电极表面能够黏附气泡,更易倾向于形成稳定的气膜;多孔结构对于亲水电极表面气泡行为的影响比对疏水电极表面气泡行为的影响更为显著;与没有多孔结构的亲水电极相比,具有多孔结构的亲水电极表面产生的气泡数量多,速率快;与较小孔径的多孔亲水电极相比,较大孔径的多孔亲水电极表面产生气泡速率快且黏附气泡数量少.该研究结果为微气泡减阻电极的设计提供了理论依据.

We have prepared copper electrodes by the hierarchical micropore hydrogen template method. By changing the plating current density and plating time, we can effectively control the size and distribution of the micropores. In addition, we altered the surface chemical composition to obtain electrodes with different wettability. The production and behavior of bubbles on the electrodes with different microstructures and wettability during the process of water electrolysis was investigated. The experimental results indicated that, compared with the hydrophilic porous electrode, the bubbles were able to pin onto the hydrophobic electrode more easily, and they tended to coalesce to form a stable gas film. The effect of the porous structure on the behavior of bubbles was more significant for hydrophilic electrodes than hydrophobic electrodes. The electrodes with hierarchical microporous structures preferred to produce more bubbles than those without microporous structures. The production rate of bubbles on the electrodes with hierarchical microporous structure was faster than that on the electrodes without. Furthermore, porous hydrophilic electrodes with large pore sizes could generate bubbles faster and pin smaller bubbles than electrodes with small pore sizes. We believe that these results can provide theoretical proof for the design of the electrodes with attached micro-bubbles to reduce drag resistance.