Will they wiggle? Determining hydrogen bubble movements during water electrolysis

Electrolysis uses electric current through a cathode and an anode to split water into its hydrogen and oxygen components, allowing the hydrogen to be captured and used as a clean energy source. During this process, little bubbles of hydrogen often stick to the cathode, wiggling and jiggling until they break away.

The micron-scale hydrogen bubbles cause a major problem, however. When they remain on the cathode, they reduce the surface area available for electrochemical reactions and increase the resistance of the system, diminishing its overall efficiency. To mitigate this issue, Duan et al. studied the electrochemistry, fluid physics, and interfacial science of the hydrogen bubble dynamics.

“These effects give rise to substantial additional overpotentials, resulting in a diminished overall energy efficiency of the electrolysis system,” said author Qiang Xu. “Therefore, gaining a comprehensive understanding of bubble evolution and conducting in-depth investigations into bubble evolution and movement are essential for the optimization of water electrolysis techniques.”

The researchers carefully tuned the voltages applied to an electrolysis system and used cameras to monitor the bubbles’ behavior. They found a critical time that determines whether the bubble will stick around and oscillate before being released, which depends on the voltage, electrolyte concentration, and the bubble’s radius. If the bubble’s evolution period — how long it takes to grow — is longer than this critical time, it oscillates.

The authors hope their work determining hydrogen bubble oscillation parameters will lead to a wider focus on the microscale phenomena involved in energy conversion processes, “where seemingly minute bubbles may represent a critical leverage point for advancing high-efficiency hydrogen production systems,” said Xu.

Source: “Dynamics of hydrogen bubble movement and oscillation on platinum microelectrodes during water electrolysis,” by Zeyuan Duan, Xuanxiang Zhao, Jinfeng Li, Yonglu She, Liejin Guo, and Qiang Xu, Applied Physics Letters (2026). The article can be accessed at https://doi.org/10.1063/5.0314697 .