A Novel Biomimetic Catalyst with Mn4‐xNixCaO5 Structure for Superior Oxygen Evolution Reaction

Abstract In natural plants, Mn 4 CaO 5 cluster with metal‐oxo “distorted chair”‐like structure exhibits excellent oxygen evolution activity. However, the performance of biomimetic oxygen evolution catalysts based on the Mn 4 CaO 5 ‐like structure is far inferior to expectations. Herein, Ca and Ni are first doped together into birnessite and constructed a “distorted chair”‐like structure unit Mn 4‐x Ni x CaO 5 in a birnessite‐like Ca‐Mn(Ni)‐O catalyst, the biomimetic Mn 4‐x Ni x CaO 5 unit efficiently activates lattice oxygen and boosts the O─O coupling in oxygen evolution reaction (OER), which allows the catalyst to perform superior OER activity with an outstanding overpotential of 184 mV at 300 mA cm −2 . Besides, the birnessite‐like Ca‐Mn(Ni)‐O catalyst is stabilized by coupling to NiMnO 3 nanoplate, thus forming a stable catalyst that can work for >500 h without attenuation. This work optimizes biomimetic structures by introducing new elements, which provides new insight into developing efficient biomimetic materials.