Self-Supportive NiFe hydroxide with High Electrocatalytic Activity for Oxygen and Hydrogen Evolution Reaction

Here, a facile method to prepare low-cost self-supportive NiFe hydroxide on etching galvanized sheet iron (EGSI) (FexNiyOOH/EGSI) for electrochemical water splitting was proposed for the first time. The EGSI was firstly treated in Fe2+, Ni2+ and urea mixture to obtain FexNiyOH/EGSI and then were further transformed into FexNiyOOH/EGSI by the electrooxidation in NaOH solution. SEM results indicated various morphologies including nanoflowers, nanosheets and cubes could be obtained depending on the ratio of Fe2+ and Ni2+. Raman spectra, XRD and electrochemical results indicated that the NiOOH was produced in electrooxidation process, which improved its catalytic activity of OER remarkably. Besides, modest Fe-doping could make it achieve better catalytic activity because Fe-doping could alter the redox properties of NiFe hydroxide to result in low overpotential. As a result, the FexNiyOOH/EGSI presented good OER and HER performances. The optimum Fe1.5Ni0.5OOH/EGSI as cathode and Fe0.2Ni1.8OOH/EGSI as anode were applied for water splitting, achieving a current density of 10 mA cm(-2) at 1.69 V, indicating that it could work at a lower potential.