Highly Efficient Alkaline Water Electrolysis Using Alkanolamine-Functionalized Zirconia-Blended Separators

Alkaline water electrolysis is one of the most promising technologies for green hydrogen production. Here, we synthesized a series of alkanolamine-modified zirconia particles by a one-pot method to construct zirconia-based composite membranes for alkaline water electrolysis. Among these membranes, the diethanolamine (DEA)-functionalized zirconia separator exhibits superior hydrophilicity with a low water contact angle of 44° and low area resistance of 0.12 Ω·cm2, which were 47 and 60%, respectively, less than that of the commercial Zirfon PERL UTP 500 separator. Conceivably, the DEA-functionalized zirconia separator presents high electrochemical performance with a current density of 1114 mA cm–2 at 2.0 V with Raney Ni as the cathode catalyst and CoMnO@CoFe layered double hydroxide (LDH) as the anode catalyst at 80 °C, closing the gap with proton exchange membrane electrolysis. In addition, the DEA-modified separator exhibits high stability for over 150 h at a high current density of 500 mA cm–2 and stable cell voltages in 30 wt % KOH at 80 °C.