How hydrogen bubbles form and behave on electrodes seems to depend on the anions in your electrolyte, researchers explain from Leiden and Twente in Nature Chemistry.

The large-scale production of hydrogen by electrolysis is really starting to take off. But to use your electricity as efficiently as possible, it is important to know what is happening at your electrodes. Ideally, you would use high current densities, but that creates bubbles at your electrode and these create resistance. ’This is a very old topic in electrochemistry: how do bubbles behave in this context?’ says Marc Koper, Professor of Electrochemistry at Leiden University.

’In classical electrochemical research, we usually use a lower current density, with a lower overpotential’, explains Koper. ’In this case, you don’t see bubbles forming, although they could be there. But at higher current densities, you get big bubbles, and bubbles create more resistance on your electrode and therefore lower efficiency.’ A few years ago, Henry White of the University of Utah started researching bubbles using micro- and nanoelectrodes. The advantage of such tiny electrodes is that you can see how a single bubble forms. ’I found this research so attractive that I started doing it myself’, Copper says.