Amino-Functionalized UiO-66 Customized Regulation Composite Membrane Performance for Efficient Alkaline Water Electrolysis

Alkaline water electrolysis (AWE) is the dominant technology for hydrogen production; however, its separators face persistent challenges, including low efficiency and poor gas barrier properties. Therefore, this study proposes a composite separator. An appropriate amount of amino-functionalized UiO-66 (UiO-66-NH2) is introduced to fill the gaps between ZrO2 particles, thereby optimizing the membrane structure. The −NH2 groups on the surface of UiO-66-NH2 can form hydrogen bonds with water, which regulate the nonsolvent-induced phase separation process and thereby construct channels more favorable for OH– transport. During electrolysis, the −NH2 groups further form a hydrogen-bonding network with the KOH electrolyte, enhancing the ion transport rate. In addition, the high specific surface area of UiO-66-NH2 helps increase the contact efficiency between the electrolyte and the membrane pores, thereby synergistically improving the electrolysis performance. Test results show that the optimal membrane, UDCM-6, exhibits a bubble point pressure of 5.72 bar and an area-specific resistance of 0.21 Ω cm2 in 10 wt % KOH. At 2 V in 10 wt % KOH at 80 °C, it delivers a current density of 0.71 A cm–2. The cell voltage remains stable during a 600 h operation under simulated industrial conditions. This separator ensures safety while achieving low energy consumption and high electrolysis efficiency, providing a design strategy for the development of AWE composite separators.