Alkali Containing Layered Metal Oxides as Catalysts for the Oxygen Evolution Reaction

Improving the efficiency of the oxygen evolution reaction (OER) is essential to realise energy systems based on water electrolysis. Many catalysts have been developed for the OER to date, with iridium-based oxides being the most promising due to their relative stability towards corrosion in acidic electrolytes under oxidising potentials. In recent years, examples of catalysts adopting layered structures have been shown to have promising characteristics such as higher conductivity and higher electrochemically active surface area compared to highly crystalline metal oxides. Furthermore, such materials possess additional tuneable properties such as interlayer spacing, identity and concentration of the interlayer species, edge and interlayer active sites, and higher active surface area. Recent attention has focused on mono- and polymetallic lithium-containing layered materials, where the presence of interlayer lithium cations, in situ delithiation processes and combinations of transition metal oxides result in enhanced catalytic properties towards OER. This review aims to provide a summary of the recent developments of such layered materials, in which lithium or other alkali metal ions occupy interlayer sites in oxides.