비백금 음이온 교환막 수전해를 위한 철 도핑 활용 니 켈-몰리브데넘 합금 촉매의 활성점 제어

Abstract

Developing advanced catalysts for the hydrogen evolution reaction in alkaline media remains a significant hurdle for the broader adoption of anion exchange membrane water electrolyzers. This study presents the synthesis of an Fe-doped Ni4Mo/MoOx catalyst through a synergistic approach involving hydrothermal and thermal reduction processes. Material characterization and electron structure analysis underscored the pivotal role of Fe, and its addition notably promoted the formation of the Ni4Mo phase, which was identified as active site of the catalyst. Further insights from density functional theory calculations revealed that Fe doping enhanced the desorption energy necessary for the H2 recombination step within the Ni4Mo phase, bolstering both the intrinsic and extrinsic activities. This enhancement propelled the NiMoFe catalyst to outperform conventional NiMo catalysts in both aqueous model system and membrane electrode assembly experiment. Notably, an anion exchange membrane water electrolysis configured with the NiMoFe catalyst at the cathode demonstrated remarkable performance, reaching a cell voltage of 1.63 V at a current density of 1 A cm-2, and preserving over 98% of its initial voltage at 0.5 A cm-2, demonstrating its potential for commercial applications.