Microwave Synthesis of Ultrathin Nickel Hydroxide Nanosheets with Iron Incorporation for Electrocatalytic Water Oxidation

Two-dimensional ultrathin nickel hydroxide nanosheets with large surface area and excellent electronic properties have been considered as promising electrocatalysts for the oxygen evolution reaction (OER). Herein, we report a facile microwave synthetic strategy to prepare ultrathin nickel hydroxide nanosheets with thickness <1 nm. In addition, varying the iron incorporation into the parent nickel hydroxide nanosheets allows us to synthesize a series of Ni1–xFex(OH)2 nanosheets without sacrificing the atomic thickness. Electrochemical studies demonstrate that Fe0.22Ni0.78(OH)2 nanosheets exhibit the best OER activity, requiring an overpotential of only 315 mV to achieve 10 mA/cm2 plus strong robustness in 1.0 M KOH. The enhanced OER performance could be mainly attributed to the intrinsically more active sites in Fe0.22Ni0.78(OH)2. Overall, our work presents a novel and facile approach to obtain ultrathin nanosheets of nickel/iron hydroxides as competent OER electrocatalysts. The microwave synthetic approach could be readily extended to prepare many other ultrathin oxides/hydroxides for various applications.