NiFe₂O₄ Material on Carbon Paper as an Electrocatalyst for Alkaline Water Electrolysis Module

NiFe₂O₄ material is grown on carbon paper (CP) with the hydrothermal method for use as electrocatalysts in an alkaline electrolyzer. NiFe₂O₄ material is used as the anode and cathode catalysts (named NiFe(+)/NiFe(-) hereafter). The results are compared with those obtained using CP/NiFe as the anode and CP/Ru as the cathode (named NiFe)(+)/Ru(-) hereafter). During cell operation with NiFe(+)/Ru(-), the current density reaches 500 mA/cm² at a cell voltage of 1.79 V, with a specific energy consumption of 4.9 kWh/m³ and an energy efficiency of 66.2%. In comparison, for NiFe(+)/NiFe(-), the current density reaches 500 mA/cm² at a cell voltage of 2.23 V, with a specific energy consumption of 5.7 kWh/m³ and an energy efficiency of 56.6%. The Faradaic efficiency is 96-99%. With the current density fixed at 400 mA/cm², after performing a test for 150 h, the cell voltage with NiFe(+)/Ru(-) increases by 0.167 V, whereas that with NiFe(+)/NiFe(-) decreases by only 0.010 V. Good, long-term stability is demonstrated.