Regulating the Electronic State of Ni in an Alloy Phase by Heterogeneous Structures of FeNi3-WC/C to Reach a High Performance for Oxygen Evolution Reaction

Abstract

The high energy barrier and multi-intermediate state of oxygen evolution reaction (OER) are the keys to limiting water decomposition. Here, we demonstrate a novel OER catalyst, which is constructed by introducing the WC impurity phase into FeNi3/C to construct FeNi3-WC/C heterostructure on the carbon skeleton, adjusting the number of active sites, improving the intrinsic activity, and accelerating the reaction kinetics. The overpotential of 240 mV and the Tafel slope of 44 mVdec−1 is obtained at a current density of 10 mA cm−2, which are superior to the traditional noble metal oxide catalyst (RuO2). The density functional theory (DFT) model shows that the charge transfer from WC heterogeneous phase to the FeNi3 alloy phase enriches the Ni d electronic state in the alloy phase, thereby enhancing the intrinsic activity of the active site, reducing the adsorption free energy of *O to *OOH, and improving the oxygen evolution reaction efficiency. This work provides a reference for the development of non-noble metal-based catalysts.