Stable and oxidative charged Ru enhance the acidic oxygen evolution reaction activity in two-dimensional ruthenium-iridium oxide

The oxygen evolution reactions in acid play an important role in multiple energy storage devices. The practical promising Ru-Ir based catalysts need both the stable high oxidation state of the Ru centers and the high stability of these Ru species. Here, we report stable and oxidative charged Ru in two-dimensional ruthenium-iridium oxide enhances the activity. The Ru0.5Ir0.5O2 catalyst shows high activity in acid with a low overpotential of 151 mV at 10 mA cm-2, a high turnover frequency of 6.84 s-1 at 1.44 V versus reversible hydrogen electrode and good stability (618.3 h operation). Ru0.5Ir0.5O2 catalysts can form more Ru active sites with high oxidation states at lower applied voltages after Ir incorporation, which is confirmed by the pulse voltage induced current method. Also, The X-ray absorption spectroscopy data shows that the Ru-O-Ir local structure in two-dimensional Ru0.5Ir0.5O2 solid solution improved the stability of these Ru centers. Stabilizing high oxidation state of Ru centers is important to achieve stable performance for acidic oxygen evolution reaction. Here the authors report two-dimensional ruthenium-iridium oxide for enhanced stability and activity for acidic water oxidation in proton exchange membrane electrolyzer.

Automated summary

The stability and activity of two-dimensional ruthenium-iridium oxide in acidic oxygen evolution reactions are enhanced. The Ru0.5Ir0.5O2 catalyst exhibits good activity and stability under acidic conditions, forming more high oxidation state Ru active sites.