Zn-Doped CoS₂ Nanoarrays for an Efficient Oxygen Evolution Reaction: Understanding the Doping Effect for a Precatalyst

Development of low-cost, efficient, and durable electrocatalysts for the oxygen evolution reaction (OER) is crucial for multiple energy conversions and storage devices. Herein, Zn-doped CoS2 nanoarrays supported on carbon cloth, Co(Zn)S2/CC, are fabricated through a facile sulfidization of CoZn metal–organic frameworks. This precatalyst, Co(Zn)S2/CC, with a well-defined nanoarray structure affords excellent OER catalytic activity (η = 248 mV at 10 mA/cm2) and long-term durability in 1 M KOH. X-ray photoelectron and in situ Raman spectroscopic studies indicate that Co(Zn)S2 undergoes surface reconstruction with the generation of Co(Zn)OOH adsorbed with SO42– at the surface during the OER process. The Zn dopant is calculated to impact on the electronic structure of Co species and further the adsorption of intermediates. This work not only provides a novel method for the synthesis of bimetallic sulfides but also gives insights into the doping effect on the OER performance of transition metal sulfides.