Recent Developments on Cr‐Based Electrocatalysts for the Oxygen Evolution Reaction in Alkaline Media

Abstract Among a plethora of transition‐metal catalysts explored for the oxygen evolution reaction (OER) in water electrolysis, the use of chromium (Cr) as a component, has only recently started to gain momentum. In this review, recent investigations where Cr has been utilised for alkaline OER has been summarised and evaluated. The Cr‐based electrocatalysts have been categorised and discussed according to their anion counterparts. From the majority of reviewed studies, Cr comes across as a beneficial co‐catalyst owing to its ability to act as either an electron acceptor or electron donor. This characteristic property stems from the many possible oxidation states of Cr, with Cr 3+ and Cr 6+ being the most pronounced states. This review emphasises on providing a holistic view of the role Cr plays in OER electrocatalysis, focussing mainly on the correlations of activity, structure, and electronic configuration.