A Molecular Approach to Manganese Nitride Acting as a High Performance Electrocatalyst in the Oxygen Evolution...

The scalable synthesis of phase-pure crystalline manganese nitride (Mn₃ N₂ ) from a molecular precursor is reported. It acts as a superiorly active and durable electrocatalyst in the oxygen evolution reaction (OER) from water under alkaline conditions. While electrophoretically deposited Mn₃ N₂ on fluorine tin oxide (FTO) requires an overpotential of 390 mV, the latter is substantially decreased to merely 270 mV on nickel foam (NF) at a current density of 10 mA cm^-2 with a durability of weeks. The high performance of this material is due to the rapid transformation of manganese sites at the surface of Mn₃ N₂ into an amorphous active MnO_x overlayer under operation conditions intimately connected with metallic Mn₃ N₂ , which increases the charge transfer from the active catalyst surface to the electrode substrates and thus outperforms the electrocatalytic activity in comparison to solely MnO_x -based OER catalysts.