Development and testing of a novel catalyst-coated membrane with platinum-free catalysts for alkaline water electrolysis

A stable, platinum-free catalyst-coated anion-exchange membrane with a promising performance for alkaline water electrolysis as an energy conversion technology was prepared and tested. A hot plate spraying technique used to deposit electrodes 35 or 120 μm thick on the surface of an anion-selective polymer electrolyte membrane. These thicknesses of 35 and 120 μm corresponding to the catalyst load of 2.5 and 10 mg cm−2. The platinum free catalysts based on NiCo2O4 for anode and NiFe2O4 for cathode were used together with anion selective polymer binder in the catalyst/binder ratio equal to 9:1. The performance of the prepared membrane-electrode assembly was verified under conditions of alkaline water electrolysis using different concentrations of liquid electrolyte ranging from 1 to 15 wt% KOH. The electrolyser performance was compared to a cell utilizing a catalyst-coated Ni foam as the electrodes. The prepared membrane-electrode assembly stability at a current load of 0.25 A cm−2 was verified by a 72-hour electrolysis test. The results of the experiments indicated the possibility of a significant reduction of the catalyst loading compared to a catalyst-coated substrate approach.