Microwave\nSynthesis of Ultrathin Nickel Hydroxide\nNanosheets with Iron Incorporation for Electrocatalytic Water Oxidation

Abstract

Two-dimensional\nultrathin nickel hydroxide nanosheets with large\nsurface area and excellent electronic properties have been considered\nas promising electrocatalysts for the oxygen evolution reaction (OER).\nHerein, we report a facile microwave synthetic strategy to prepare\nultrathin nickel hydroxide nanosheets with thickness <1 nm. In\naddition, varying the iron incorporation into the parent nickel hydroxide\nnanosheets allows us to synthesize a series of Ni_1–<i>x</i>Fe_<i>x</i>(OH)₂ nanosheets\nwithout sacrificing the atomic thickness. Electrochemical studies\ndemonstrate that Fe_0.22Ni_0.78(OH)₂ nanosheets exhibit the best OER activity, requiring an overpotential\nof only 315 mV to achieve 10 mA/cm² plus strong robustness\nin 1.0 M KOH. The enhanced OER performance could be mainly attributed\nto the intrinsically more active sites in Fe_0.22Ni_0.78(OH)₂. Overall, our work presents a novel and\nfacile approach to obtain ultrathin nanosheets of nickel/iron hydroxides\nas competent OER electrocatalysts. The microwave synthetic approach\ncould be readily extended to prepare many other ultrathin oxides/hydroxides\nfor various applications.