Rapid Outgassing of Hydrophilic TiO2 Electrodes Achieves Long-Term Stability of Anion Exchange Membrane Water Electrolyzers

The state-of-the-art anion-exchange membrane water electrolyzers (AEMWEs) require highly stable electrodes for prolonged operation. The stability of the electrode is closely linked to the effective evacuation of H₂ or O₂ gas generated from electrode surface during the electrolysis. In this study, we prepared a super-hydrophilic electrode by depositing porous nickel-iron nanoparticles on annealed TiO₂ nanotubes (NiFe/ATNT) for rapid outgassing of such nonpolar gases. The super-hydrophilic NiFe/ATNT electrode exhibited an overpotential of 235 mV at 10 mA cm^-2 for oxygen evolution reaction in 1.0 M KOH solution, and was utilized as the anode in the AEMWE to achieve a current density of 1.67 A cm^-2 at 1.80 V. In addition, the AEMWE with NiFe/ATNT electrode, which enables effective outgassing, showed record stability for 1500 h at 0.50 A cm^-2 under harsh temperature conditions of 80 ± 3 °C.