Applicability of Non-PGM Bi-Functional Electrocatalyst in a Scaled-up Anion Exchange Membrane Water Electrolysis

While non-precious metal catalyst materials are crucial for AEMWE systems, catalyst substances possessing both adequate hydrogen molecule adsorption ability and suitable electrical conductivity and hydrophilicity are still in the developmental stage. Ni-Mo alloy metals are known as those that have appropriate hydrogen molecule adsorption binding energy, making them excellent electrochemical catalysts for the cathode. However, they suffer from a high content of oxide, which hampers electrical conductivity, and the formation of a high oxidation state of Ni molecules, making hydrogen molecule detachment challenging. On the other hand, Ni-Fe alloys are recognized for their excellent -OOH group adsorption ability and high electrical conductivity, and that has a low oxidation state Ni phase for high hydrogen desorption ability. Therefore, in this study, we aimed to synthesize NiMoFe-based alloy catalysts to enhance the hydrogen evolution reaction (HER) activity of Ni-Mo group catalysts while simultaneously increasing the oxygen evolution reaction (OER) activity. Using a hydrothermal synthesis method for NiMoFe catalysts we employed a high-temperature thermal reduction process to minimize the oxide layer that has poor conductivity. Evaluation of the catalyst activity through half-cell experiments demonstrated low overpotentials in both Overall water electrolysis reactions. Furthermore, an MEA-type experiment was conducted to evaluate the applicability of single-cell. Furthermore, Stability tests confirmed a stable voltage. Finally, when compared to the combination of precious metal catalysts, this exhibited superior performance. Therefore, this study suggests that non-noble catalysts could serve as a crucial stepping stone, surpassing PGM metal catalysts in alkaline media.