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

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing cost-effective and earth-abundant electrocatalysts for the oxygen evolution reaction (OER) is crucial for energy storage and conversion.
• Dual-active heterostructures offer enhanced catalytic properties compared to single components.

Purpose of the Study:

• To synthesize and characterize a novel dual-active CC@CoS2/MoS2 heterostructure electrocatalyst.
• To evaluate the OER performance and stability of the synthesized catalyst.
• To elucidate the catalytic mechanism through theoretical calculations.

Main Methods:

• Solvothermal synthesis of CoS2/MoS2 nanosheets on carbon cloth.
• Electrochemical characterization including cyclic voltammetry (CV) and linear sweep voltammetry (LSV).
• Density Functional Theory (DFT) calculations to determine the reaction mechanism and energy barriers.

Main Results:

• The CC@CoS2/MoS2 heterostructure exhibited a low OER overpotential of 243 mV at 10 mA cm-2 and a Tafel slope of 109 mV dec-1.
• The catalyst demonstrated excellent stability over 1000 CV cycles and long-term operation (>60 h).
• Theoretical calculations identified the *O + OH- → *OOH + e- step as rate-determining with a reduced energy barrier of 1.49 eV due to the heterojunction.

Conclusions:

• The CC@CoS2/MoS2 heterostructure is a highly efficient and stable electrocatalyst for OER.
• The synergistic effect between CoS2 and MoS2 in the heterojunction significantly enhances OER performance.
• Understanding the catalytic mechanism provides insights for designing advanced electrocatalysts for OER applications.