In a novel study, researchers of the University of Twente have made significant strides in understanding the behaviour of micro- and nanobubbles on electrodes during water electrolysis. This process is crucial for (green) hydrogen production. These tiny bubbles form on the electrodes, blocking the flow of electricity and reducing the efficiency of the reaction.
A renewable hydrogen economy significantly reduces the impact of global warming compared to a fossil fuel economy. However, the production of hydrogen is significantly impeded by bubbles at the micro- and nanoscale. Therefore, researchers at the University of Twente try to precisely understand how these tiny bubbles form on and stick to the electrodes, to finally get rid of them.
Prediction bubble behaviour
Supported by advanced molecular simulations, Detlef Lohse and his team developed a theory which can successfully predict the electrical current density needed to let the nanobubbles grow uncontrollably and detach, thus freeing the electrode for further hydrogen production. This finding is pivotal as it allows for the prediction and control of bubble behaviour, ensuring that electrolysis can proceed with minimal disruption. The research builds upon the established stability theory for surface nanobubbles (Lohse-Zhang model) and extends it to include the electrolytic current density to predict the bubble behaviour.
With the improved knowledge, scientists and engineers can now work towards enhancing the detachment of bubbles. Besides improving the overall efficiency of water electrolysis, this work can be used also for other systems where gas bubbles are formed, such as in catalysis.
More information
This research was performed by Dr Yixin Zhang (Physics of Fluids Group; Faculty of S&T) Dr Xiaojue Zhu (Max Planck Institute for Solar System Research Göttingen Germany), Jeffery A. Wood (Membrane Science and Technology Cluster; MESA+ Institute for Nanotechnology) and Detlef Lohse (Physics of Fluids Group). They recently published their work in an article, entitled ‘Threshold Current Density for Diffusion-controlled Stability of Surface Electrolytic Nanobubbles’, in the scientific journal PNAS (Proceeding of the National Academy of Science).
