Experimental investigation on bubble growth and detachment characteristics on vertical microelectrode surface under electrode-normal magnetic field in water electrolysis

The effects of current density and electrode-normal magnetic fields on the growth and detachment characteristics of a single bubble on vertical microelectrode surface have been investigated. A high-speed camera was used to capture the bubble evolution behavior and the bubble contact characteristic parameters were extracted and analyzed with OpenCVPython program. The results reveal that an apparent bubble coalescence behavior occurs at low current densities and can be gradually inhibited with increasing current density. With the increase of current density, the bubble growth rate, departure diameter, working electrode potential and potential fluctuations increase, while the bubble growth time first increases and then decreases continuously. The upper microelectrode surface is more easily covered than the lower microelectrode surface. The whole microelectrode can be completely covered when the current density exceeds a certain limit with and without magnetic fields. The external magnetic fields can obviously promote the bubble detachment behavior within a relatively large current density range. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The effects of current density and electrode-normal magnetic fields on the growth and detachment characteristics of a single bubble on vertical microelectrode surface have been investigated. The results reveal that bubble coalescence behavior occurs at low current densities and can be gradually inhibited with increasing current density; external magnetic fields promote the bubble detachment behavior within a relatively large current density range.