Lattice oxygen activation through reconstruction of transition metal fluoride for efficient ampere-level current density oxygen evolution

Abstract

The oxygen evolution reaction (OER) characterized by its sluggish kinetics, poses a significant impediment to the efficiency of electrochemical water splitting technology, which underscores the pressing necessity for the development of efficient OER electrocatalysts. The lattice oxygen mechanism (LOM) is capable of surmounting the constraints associated with the theoretical overpotential of adsorbate evolution mechanism (AEM), thereby offering a potential approach for designing highly efficient OER electrocatalysts. However, the rational design of LOM-based OER electrocatalysts remains a considerable challenge. Herein, we report the synthesis of a novel multicomponent transition metal fluoride electrocatalyst, NiF2/FeFx, which can be restructured into oxyhydroxides that follow the LOM pathway, via a straightforward co-precipitation method. A comprehensive set of experimental results demonstrates that the formation of multicomponent fluorides, induced by the incorporation of Fe, can promote structural reconstruction and inducing LOM pathway. Consequently, the resulting NiF2/FeFx exhibits superior OER activity, requiring overpotentials of 278, 336, and 371 mV to derive 100, 500, and 1000 mA cm-2, respectively. Moreover, NiF2/FeFx demonstrates excellent storage stability, maintaining its activity for over 90 days without notable degradation. This study introduces an innovative LOM-based OER electrocatalyst and also offers significant perspectives for creating high-performance OER electrocatalysts.