Heterostructure CoS₂/MoS₂ Nanosheets as a Dual-Active Electrocatalyst for the Oxygen Evolution Reaction

Abstract

Cost-effective and earth-abundant oxygen evolution reaction (OER) electrocatalysts are an incredible research hotspot in numerous energy storage and conversion technology fields. Herein, CoS₂/MoS₂ nanosheets supported by carbon cloth as a dual-active CC@CoS₂/MoS₂ heterostructure electrocatalyst is prepared through a simple solvothermal method. The catalyst demonstrates admirable OER performance in 1 M KOH solution with a low overpotential of 243 mV at a current density of 10 mA cm^-2 and a minor Tafel slope of 109 mV dec^-1, displaying honorable stability after 1000 cyclic voltammetry (CV) cycles and long-term robustness over 60 h. Theoretical calculations further ascertain that the rate-determining step of the electrocatalytic course of the CC@CoS₂/MoS₂ heterostructure is the conversion *O + OH^- → *OOH + e^- with a lower energy barrier of 1.49 eV due to the heterojunction established by CoS₂ and MoS₂, which can promote the OER performance of electrocatalysts. The actual identification of the catalytic mechanism in the heterostructure is conducive to the improvement of electrocatalysis applications in the OER.