Boosting the Stability of RuO2 in the Acidic Oxygen Evolution Reaction by Tuning Oxygen-Vacancy Formation Energies: A Viable Approach Beyond Noble-Metal Catalysts?

RuO2 belongs to the most active electrode materials for the anodic oxygen evolution reaction (OER) within the electrochemical water splitting, such as those encountered in acidic proton-exchange membrane (PEM) electrolyzers. Despite its large activity, RuO2 faces severe stability issues under the harsh anodic operation conditions. Now, a new strategy has been reported to overcome this bottleneck by tuning the free-formation energy of oxygen vacancies, which can be achieved by the co-doping of W and Er into the RuO2 lattice. The resulting W0.2Er0.1Ru0.7O2-delta electrocatalyst is stable long term in acid and, additionally, reveals remarkable OER activity, about 30 times higher than that of commercial RuO2. The notion of tuning the oxygen-vacancy formation energy could be a valuable starting point for the development of non-noble electrocatalysts for the acidic OER with applications in PEM electrolyzers.

Automated summary

RuO2 is a highly active electrode material, but faces stability issues under acidic conditions. Co-doping W and Er can tune the free-formation energy of oxygen vacancies in the RuO2 lattice, resulting in the stable and significantly higher OER activity of W0.2Er0.1Ru0.7O2-delta electrocatalyst.