不同电解质浓度下光电极上单个气泡的生长特性及传质机制,Physical Chemistry Chemical Physics

当前位置： X-MOL 学术 › Phys. Chem. Chem. Phys. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

不同电解质浓度下光电极上单个气泡的生长特性及传质机制
Physical Chemistry Chemical Physics ( IF 2.9 ) Pub Date : 2023-09-29 , DOI: 10.1039/d3cp03016d
Mengsha Wang ₁ , Qiang Xu ₁ , Tengfei Nie ₁ , Xinyi Luo ₁ , Yonglu She ₁ , Liejin Guo ₁

Affiliation

在光电化学水分解反应中，工作电极上附着的气泡是影响反应电阻、电流密度和气液传质的重要因素。提出了一种基于电化学工作站与高速显微相机同步耦合的实验测量系统，系统研究了不同电解质浓度（Na 2 SO 4 ，0.1~2.0 M）下单个氧气泡的生长动力学和_传质_机制。）在TiO ₂光电阳极表面上。在恒压恒流控制条件下，当电解液浓度增大时，气泡脱离直径和气泡脱离频率逐渐减小。提出了以气体逸出效率表示的气泡覆盖方程，并将其与光电流和气泡半径相关联。当电解质浓度增加时，平均气泡覆盖率和平均气体逸出效率降低。根据舍伍德无量纲数，计算了气泡生长过程中的各种传质系数。结果表明，平均总传质系数与电解质浓度的变化趋势呈正相关，单相自然对流的传质系数比气泡诱导对流的传质系数大1个数量级。最后得出气泡演化过程中瞬态传质过程的结论，即单相自然对流传质系数和总传质系数在第一个生长阶段保持较高水平，在生长阶段逐渐下降。第二个成长阶段。因此，调节电解质浓度可以有效促进光电化学分解水反应中的气液传质。

"点击查看英文标题和摘要"

Growth characteristics and the mass transfer mechanism of single bubble on a photoelectrode at different electrolyte concentrations

In the photoelectrochemical water splitting reaction, the bubble attached to the working electrode is an essential factor affecting the reaction resistance, current density and gas–liquid mass transfer. An experimental measurement system based on an electrochemical workstation synchronously coupled with a high-speed microscopic camera was proposed and used to systematically study the growth kinetics and mass transfer mechanism of single oxygen bubbles at different electrolyte concentrations (Na₂SO₄, 0.1–2.0 M) on the TiO₂ photoanode surface. Under constant voltage and constant current control conditions, when the electrolyte concentration increases, the bubble detachment diameter and the bubble detachment frequency gradually decrease. The bubble coverage equation expressed in terms of gas evolution efficiency is proposed and is associated with the photocurrent and bubble radius. The average bubble coverage and average gas evolution efficiency decrease when the electrolyte concentration is increased. According to the Sherwood dimensionless number, various mass transfer coefficients during bubble growth were calculated. The results show that the average total mass transfer coefficient is positively correlated with the change trend of the electrolyte concentration, and the mass transfer coefficient of single-phase natural convection is one order of magnitude larger than the mass transfer coefficient of bubble-induced convection. Finally, a conclusion on the transient mass transfer process in the bubble evolution process was obtained, that is, the mass transfer coefficient of single-phase natural convection and the total mass transfer coefficient remain high during the first growth stage, and gradually decrease during the second growth stage. Therefore, regulating the electrolyte concentration can effectively promote the gas–liquid mass transfer in the photoelectrochemical water splitting reaction.

更新日期：2023-09-29

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南