Fe doping and interface engineering-induced dual electronic regulation of CoSe2/Co9S8 nanorod arrays for enhanced electrochemical oxygen evolution

Abstract

Accurately engineering the electronic configuration of electrocatalysts to enhance their electrocatalytic performance is of importance in water splitting applications. Herein, a dual electronic regulation concept through constructing Fe-incorporated CoSe₂ and Fe-incorporated Co₉S₈ heterostructure nanorod arrays directly grown on a carbon cloth substrate (abbreviated as Fe-(CoSe₂/Co₉S₈)@CC hereafter) is demonstrated. Owing to the synergistic effect of Fe doping and CoSe₂/Co₉S₈ heterointerfaces, the resultant Fe-(CoSe₂/Co₉S₈)@CC electrode exhibits an accelerated charge transfer rate, improved electrical conductivity and sufficient active sites, thereby exhibiting excellent oxygen evolution reaction (OER) performance. Specifically, the engineered Fe-(CoSe₂/Co₉S₈)@CC electrode only requires low overpotentials of 243 and 337 mV to afford current densities of 10 and 300 mA cm⁻², respectively, and shows a low Tafel slope of 44.5 mV dec⁻¹, an ideal faradaic efficiency of nearly 100%, and prominent long-term durability in an alkaline medium. This adopted double optimization strategy provides valuable guidance for the development of low-cost and high-performance transition metal-based electrocatalysts in the energy conversion field.