Efficiently Electrocatalytic Overall Water Splitting over Ni0.85Se-Ni Foam Electrode Modified with Nanoneedle-Like Ni3Fe alloy.

Abstract

Electrocatalytic splitting of H2O into H2 and O2 is one of the potential ways to develop clean and storable energy. In this study, the self-supporting Ni0.85Se-Ni foam (Ni0.85Se-NF) hybrid electrode was modified with Ni3Fe (Ni3Fe/Ni0.85Se-NF) via facile selenization and electrochemical deposition method. The Ni3Fe/Ni0.85Se-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 Ni0.85Se-NF and Ni3Fe/NF. In particular, the Ni3Fe/Ni0.85Se-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 Ni3Fe/Ni0.85Se-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 Ni3Fe/Ni0.85Se-NF electrode after the HER or OER test. Some Ni and Fe species were found to convert to the NixFe1-xOOH during water electrocatalysis.