Improved Oxygen Evolution Reaction Kinetics with Titanium Incorporated Nickel Ferrite for Efficient Anion Exchange Membrane Electrolysis

Anion exchange membrane water electrolysis (AEMWE) is attracting attention as a next-generation technology for producing hydrogen from water. To maximize the efficiency of AEMWE systems, electrodes fabricated using nonprecious metal catalysts that possess high activity and durability are required to make the AEMWE system operable in alkaline environments. In this study, we investigate the effect of Ti impurities on the oxygen evolution reaction (OER) kinetics of NiFe₂O₄ (NFO). Ti impurities can improve the electrical conductivity of NFO and accelerate the OER kinetics. The overpotential of the fabricated OER anode displays current densities of 10 and 100 mA cm^-2 at 230 and 300 mV, respectively, which are lower overpotentials than those of pristine NFO (10 and 100 mA cm^-2 at 260 and 380 mV). The AEMWE single-cell with a Ti-NFO electrode as the anode shows high performance (0.5 A cm^-2 at 1.61 V_Cell and 1.0 A cm^-2 at 1.73 V_Cell) and durability (at 0.5 A cm^-2 for 500 h). Thus, it outperforms most of the reported single-cells assembled using NiFe-based catalysts. This study demonstrates the successful utilization of Ti impurities in the mass production of catalysts, addressing the intrinsic electrical conductivity issues of NFO for AEMWE systems.