Iodide salts make biocatalysts stable for fuel cells

In Germany, oxygen inactivates biocatalysts for energy conversion even under a protective film within a short time and researchers at the Ruhr University Bochum discovered that the addition of iodide salts to the electrolyte can prevent this and considerably extend the life of the catalysts.

Biological and bio-inspired catalysts abound, and their catalytic performance is close to that of precious metal catalysts. Nevertheless, they are not used across the board for energy conversion processes. The reason for this is their instability. “Some of the most active catalysts for converting small molecules, which are relevant for sustainable energy systems, are so sensitive to oxygen that they are completely deactivated within seconds when they come into contact with them,” explains Nicolas Plumeré.

The research team was able to demonstrate that the breakdown of hydrogen peroxide using iodide salts increases the half-life of a hydrogenase for hydrogen oxidation with constant conversion to up to a week, even if constantly high oxygen concentrations act on it. “Overall, our data confirm the theory that redox films make oxygen-sensitive catalysts completely immune to direct deactivation by oxygen,” Plumeré summarizes. “But it is very important to suppress hydrogen peroxide production in order to achieve complete protection against oxidative stress.”