Interface prompted highly efficient hydrogen evolution of MoS₂/CoS₂ heterostructures in a wide pH range

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Interfacial electronic characteristics are critical for nanoscale heterogeneous catalysts, particularly for the hydrogen evolution reaction (HER).
• Existing catalysts often face limitations in activity and stability across diverse pH conditions.

Purpose of the Study:

• To investigate the synergistic effects of CoS2 and MoS2 heterostructures on HER activity.
• To elucidate the underlying mechanisms responsible for enhanced catalytic performance.

Main Methods:

• Fabrication and characterization of 2H-MoS2/CoS2 and 1T-MoS2/CoS2 heterostructures.
• Electrochemical measurements including overpotential and Tafel slope analysis.
• Theoretical calculations of Gibbs free energies for hydrogen adsorption and exchange current density.

Main Results:

• MoS2/CoS2 heterostructures exhibit significantly enhanced HER activity compared to individual components across acidic and alkaline media.
• Calculated Gibbs free energies for hydrogen adsorption at interfacial Co sites are highly favorable, surpassing those of Pt(111).
• Experimental results show reduced overpotentials (54 mV acidic, 46 mV alkaline) and favorable Tafel slopes (42 mV/dec acidic, 50 mV/dec alkaline).

Conclusions:

• The synergistic activation of interfacial Co atoms in MoS2/CoS2 heterostructures is key to improved HER performance.
• Enhanced electron conductivity and optimized hydrogen adsorption characteristics contribute to superior catalytic activity.
• MoS2/CoS2 presents a promising class of electrocatalysts for efficient hydrogen evolution.