Oxyanion Engineering Suppressed Iron Segregation in Nickel-Iron Catalysts Toward Stable Water Oxidation.

Nickel-iron catalysts represent an appealing platform for electrocatalytic oxygen evolution reaction (OER) in alkaline media because of their high adjustability in component and activity. However, their long-term stabilities under high current density still remain unsatisfactory due to undesirable Fe segregation. Herein, we developed a nitrate ion (NO 3 - ) tailored strategy to mitigate Fe segregation, and thereby improve the OER stability of nickel-iron catalyst. X-ray absorption spectroscopy combined with theoretical calculations indicate that introducing Ni 3 (NO 3 ) 2 (OH) 4 with stable NO 3 - in the lattice is conducive to constructing the stable interface of FeOOH/Ni 3 (NO 3 ) 2 (OH) 4 via the strong interaction between Fe and incorporated NO 3 - . Time of flight secondary ion mass spectrometry and wavelet transformation analysis demonstrate that the NO 3 - tailored nickel-iron catalyst greatly alleviates Fe segregation, exhibiting a considerably enhanced long-term stability with a six-fold improvement over FeOOH/Ni(OH) 2 without NO 3 - modification. Our work represents a momentous step toward regulating Fe segregation for stabilizing the catalytic performances of nickel-iron catalysts. This article is protected by copyright. All rights reserved.