Efficiently Electrocatalytic Overall Water Splitting over Ni 0.85 Se‐Ni Foam Electrode Modified with Nanoneedle‐Like Ni 3 Fe Alloy

Abstract Electrocatalytic splitting of H 2 O into H 2 and O 2 is one of the potential ways to develop clean and storable energy. In this study, the self‐supported Ni 0.85 Se‐Ni foam (Ni 0.85 Se‐NF) hybrid electrode was modified with Ni 3 Fe (Ni 3 Fe/Ni 0.85 Se‐NF) via a facile selenization and electrochemical deposition method. The Ni 3 Fe/Ni 0.85 Se‐NF hybrid electrode exhibited excellent performance of electrocatalytic overall water splitting in an alkaline solution (1  m KOH, pH = 13.9), which is much more active than the individual Ni 0.85 Se‐NF and Ni 3 Fe/NF. In particular, the Ni 3 Fe/Ni 0.85 Se‐NF hybrid electrode generated 10 mA cm −2 cathodic current at an overpotential of 81 mV, and 10 mA cm −2 anodic current at an overpotential of 209 mV in KOH solution (1  m , pH = 13.9), respectively. In addition, only 1.68 V potential was required to generate 12 mA cm −2 current in a two‐electrode system for overall water splitting in an alkaline aqueous solution using the Ni 3 Fe/Ni 0.85 Se‐NF working as the anode and cathode, respectively. The TEM images and Raman spectra results indicated that the microstructure reconstruction happened on the surface of the Ni 3 Fe/Ni 0.85 Se‐NF electrode after the HER or OER test. Some Ni and Fe species were found to convert to the Ni x Fe 1‐x OOH during water electrocatalysis.