More hydrogen and better fuel cells: A new look at the basics

When a water molecule releases a proton, it becomes hydroxide. However, such a proton likes to take an electron with it. And a proton together with an electron ultimately is hydrogen, the substance that is regarded as an important component of low-emission and environmentally friendly energy production.

This water electrolysis, the reaction that describes the splitting of water into oxygen and hydrogen, has now yielded some new findings.

The reaction rate at which protons and therefore also electrons are exchanged was investigated. These processes are just as crucial for the use of green electricity to produce hydrogen as they are for the conversion of hydrogen into electricity within a fuel cell.

Even batteries and accumulators function fundamentally according to this principle. Positively (protons) and negatively (electrons) charged particles are exchanged, each concentrating on one side and thus creating a potential or voltage difference. Current flows.

Contrary to expectations, the two particles that are formed from two water molecules behave quite differently. According to research at MIT, positively charged hydronium and negative hydroxide in equilibrium do not balance the reaction.

Instead, the exchange back and forth occurs at the same rate when the pH of the solution is 10. This means that hydroxide occurs a million times more frequently than hydronium. Only then does the exchange of protons and electrons take place in unison.

"Our finding is really eye-opening because it means that the assumption that people are using to analyze everything from fuel cell catalysis to hydrogen evolution may be something we need to revisit", says Yogesh Surendranath, lead author of the study.

So there is a good chance that many fundamental processes of power generation using chemical reactions in fuel cells, batteries or accumulators will undergo some exciting innovations in the near future.