Hydrolysis of NiSO4 and FeSO4 Mixture in Microdrops of Their Aqueous Solution Deposited at the Surface of an Alkali Solution and Obtaining Vase-Like Microcapsules with Walls of Ni(II) and Fe(III) Double Hydroxide

The application of microdrops of an aqueous solution of a mixture of NiSO4 (c 0.4 mol/L) and FeSO4 (c 0.1 mol/L) salts at the surface of a solution of a mixture of NaOH (c 1 mol/L) and NaBH4 (c 0.5 mol/L) has led to rapid hydrolysis of nickel(II) and iron(II) salts and the formation of open vase-like microcapsules with diameter of 1–10 μm and 20–40 nm thick walls of Ni(II) and Fe(III) double hydroxide the microdroplet–solution interface. These microcapsules can be transferred from the solution surface to the surface of the nickel electrode using the vertical elevator technique. The study of the electrochemical properties of such electrodes has shown that they are active electrocatalysts in the oxygen evolution reaction during water electrolysis in an alkaline medium and they are characterized by the overpotential value of 280 mV and Tafel slope of 69.1 mV/dec.