Optimizing Perovskites for the Water-Splitting Reaction

The electron occupation of orbitals in transition metal oxides guided the identification of an efficient oxygen evolution catalyst based on Earth-abundant elements. Electrochemical splitting of water into molecular oxygen (O2), protons, and electrons could provide a way to store the electricity generated from sustainable but intermittent energy sources, such as wind and solar power, as fuels (1). Hydrogen would be the simplest fuel to make, but the protons and electrons could be used to produce hydrocarbons and alcohols from CO2 or ammonia from N2. A major challenge is that efficient catalysts for water electrolysis are expensive and contain rare noble metals, so cost-effective approaches will require the discovery of efficient electrocatalysts that contain only Earth-abundant elements. On page 1383 of this issue, Suntivich et al. (2) describe a method for rational design of metal oxide catalysts for the oxygen evolution reaction. They discovered perovskite-structure catalysts based on non-noble metals that work with a higher efficiency than one of the state-of-the-art catalysts, iridium oxide.