Stability of electrocatalysts for water splitting
Iridium oxide is the state-of-the-art electrocatalyst for the oxygen evolution reaction in water electrolyzers, as it combines good activity with excellent stability. However, the crustal abundance of iridium is very low. Therefore, the large-scale use of water electrolyzers will be possible only if the iridium loading is significantly decreased and the intrinsic activity of IrO2 is maximized. The latter is possible by alloying IrO2 with RuO2, but the inferior stability of ruthenium is a problem for the use of iridium-ruthenium mixed oxides in a real system. We utilized the SFC-ICP-MS couple to determine whether there is a region of RuO2 compositions that allows activitiy enhancement without being detrimental for the catalyst stability. The SFC-ICP-MS couple allows the simultaneous detection of iridium and ruthenium when dissolved from Ir-Ru material libraries of gradient composition, under the oxygen evolution condtions. The gradients were prepared in-house, using physical vapor deposition (PVD) equipped with two sputtering targets.
- On the origin of the improved ruthenium stability in RuO2−IrO2 mixed oxides, Journal of The Electrochemical Society, 2016, 163, F3099-F3104.
- Oxygen and hydrogen evolution reactions on Ru, RuO2, Ir, and IrO2 thin film electrodes in acidic and alkaline electrolytes: A comparative study on activity and stability, Catalysis Today, 2016, 262, 170-180.