One-step electrosynthesis of NiFe-NF electrodes for highly efficient overall water splitting

Abstract As a promising hydrogen production method, alkaline water electrolysis has the main disadvantage of high energy consumption. Although some electrodes prepared by hydrothermal synthesis have excellent performance, the cumbersome preparation process cannot meet the future application. Here, we fabricated the electrode with schistose stacked hemispherical structure by DC electroplating at high current density for a long time, subsequently, the composition of the electrode was changed by continuous redox reaction. The electrode combine the excellent hydrogen and oxygen evolution characteristics of Ni and Fe elements, and has a large specific surface area, which means that it can provide more active site in HER and OER, thus, the overpotential can be greatly reduced. The electrode has excellent performance of HER, with overpotential of 41 mV and 132 mV at current density of 10 and 100 mA cm−2, respectively, in 1 M potassium hydroxide solution. In OER, the overpotential is 270 mV at current density of 100 mA cm−2. In overall water splitting test, the electrode only needs 1.54 V to reach 10 mA cm−2. At the same time, the prepared electrodes have good stability, and the cell voltage increases by only 1.4% even at 300 mA cm−2 current density for 40 h.