CoOOH-Modified Zirconia Composite Porous Membranes for Enhanced Alkaline Water Electrolysis

Alkaline water electrolysis (AWE) offers a cost-effective pathway for green hydrogen production. However, AWE performance is often limited by the membrane. Herein, we synthesized in situ ZrO2/CoOOH-x nanoparticles and employed them as both the catalyst and filler for an AWE composite membrane, which achieved highly efficient water electrolysis. Furthermore, the ZrO2/CoOOH-10 membrane demonstrated optimal hydrophilicity with a contact angle of 38.9°, a surface roughness of 149 nm, an area resistance of 0.2 Ω cm2, and a hydroxide conductivity of 278.4 mS cm–1. In an AWE electrolyzer with NiFe foam/NiMo foam electrodes as the anode and cathode, respectively, the ZrO2/CoOOH-10 membrane reached 1777 mA cm–2 at the cell voltage of 2.0 V in 30 wt % KOH (80 °C), while maintaining stable operation for 150 h. Mechanistic studies revealed that CoOOH had dual synergistic effects on AWE performance: (1) enhanced hydrophilicity and (2) improved ionic conductivity and electrocatalytic activity. This work establishes a new method for designing multifunctional membranes, significantly advancing the development of AWE.