Introduction of Mn(iii) to regulate the electronic structure of fluorine-doped nickel hydroxide for efficient water oxidation

Abstract

OER is the key step to increase the rate of water-splitting reaction. Design and construction of appropriate defects is an effective strategy to enhance catalytic activity. Mn has stronger e⁻–e⁻ repulsion by the local influence of its 3d orbital electrons. When Mn(III) was successfully introduced into two dimensional F-doped Ni(OH)₂, it can tune the surface electronic structure of the F-doped Ni(OH)₂ to increase its oxygen deficiency content. In this work, the as-synthesized Mn and F co-doped Ni(OH)₂–NF on Ni foam (Mn–F/Ni(OH)₂–NF) shows remarkable oxygen evolution performance, exhibiting 233 mV overpotential at 20 mA cm⁻², and the Tafel slope is 56.9 mV dec⁻¹ in 1 M KOH. The performance is better than that of the same loading of IrO₂ on Ni foam. Density functional theory (DFT) calculations further show that the introduction of oxygen defects can significantly improve the OER catalytic performance of Mn–F/Ni(OH)₂–NF.