The regulation of bubble dynamics on the photoelectrode surface through the application of external physical fields significantly influences the efficiency of photoelectrocatalytic reactions. This study investigates the evolution and detachment characteristics of bubbles on the photoelectrode surface under varying flow velocities and laser powers, focusing on the impact of shear flow on mass transfer and gas evolution efficiency. The results indicate that increasing flow velocities effectively enhance the reaction current within the system. Notably, for single bubbles, the effect of flow velocity on the reaction current is significantly more pronounced at high laser power than at low laser power. Shear flow promotes the detachment of bubbles from the photoelectrode surface, with the detachment diameter decreasing as the flow velocity increases. Additionally, applying a shear flow field enhances convective flow on the photoelectrode surface. Consequently, the combined mass transfer coefficient on the surface of the photoelectrode increases with increasing flow velocity, wherein the forced convection mass transfer plays a predominant role. However, higher mass transfer rates correspond to a decline in gas evolution efficiency for single-bubble electrodes. In addition to single bubbles, the results for multiple bubbles reveal that the number of bubbles on the photoelectrode surface initially increases and then decreases with increasing flow velocity. This study provides valuable guidance for the rational utilization of shear flow fields and the regulation of the bubble evolution process, thereby contributing to the enhancement of the photoelectrocatalytic system reaction efficiency.

中文翻译：

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剪切流场对光电化学水分解过程中气泡行为的影响


通过施加外部物理场对光电电极表面气泡动力学的调节显着影响光电催化反应的效率。本研究研究了不同流速和激光功率下光电电极表面气泡的演化和分离特性，重点研究了剪切流对传质和气体析出效率的影响。结果表明，增加流速可以有效地增强系统内的反应电流。值得注意的是，对于单个气泡，流速对反应电流的影响在高激光功率下明显比在低激光功率下更明显。剪切流促进气泡从光电电极表面分离，分离直径随着流速的增加而减小。此外，施加剪切流场增强了光电电极表面的对流。因此，光电电极表面的综合传质系数随着流速的增加而增加，其中强制对流传质起主要作用。然而，较高的传质速率对应于单气泡电极的气体析出效率下降。除了单个气泡外，多个气泡的结果表明，随着流速的增加，光电电极表面上的气泡数量最初增加，然后减少。本研究为合理利用剪切流场和调控气泡析出过程提供了有价值的指导，从而有助于提高光电催化体系的反应效率。