A Review of Nanostructured Transition Metal Phosphide-Driven Electrocatalytic Oxygen Evolution Reaction

The H₂-mediated energy transduction strategy emerged as one of the best options in our journey toward a carbon-neutral energy infrastructure where the water-splitting reaction remains a key component. Oxygen evolution reaction (OER) is one of the principal segments of water electrolysis as well as hydrogen production. However, the OER is a slow reaction in nature and demands the intervention of a catalyst to drive it at a commendable rate and efficiency, ensuring its practical application. In recent years, phosphide-based materials have emerged as unique electrocatalysts triggering oxygen evolution from water. In this Review, the potential role of transition metal phosphides (TMPs) as the anodic material in electrocatalytic water splitting has been depicted in detail. The remarkable reactivity of bimetallic nickel-iron phosphide (NiFeP), which deploys multiple redox sites leading to electrochemical bidirectionality and extensive stability, is highlighted. We have also outlined the rationale for heterostructure design with varying elemental combinations and nanocomposite morphologies to upgrade the OER activity. Furthermore, we have also highlighted upcoming challenges lying ahead of these materials before they can be inducted as next-generation catalytic materials for large-scale applications.