CoS₂-MoS₂ Nanoflower Arrays for Efficient Hydrogen Evolution Reaction in the Universal pH Range

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Water splitting requires highly active electrocatalysts.
• Polyoxometalates (POMs) offer unique structures and electrocatalytic properties.
• Molybdenum disulfide (MoS₂) is a promising electrocatalyst but requires optimization.

Purpose of the Study:

• To design and synthesize novel bimetallic sulfide nanocomposites for enhanced water splitting.
• To investigate the effect of incorporating cobalt onto MoS₂ for improved electrocatalytic activity.
• To utilize POMs as a strategy to increase active sites on MoS₂.

Main Methods:

• Synthesis of CoS₂-MoS₂ nanocomposites using a POM-based precursor (Co₂Mo₁₀) under hydrothermal conditions.
• Electrocatalytic evaluation of the synthesized nanocomposites for hydrogen evolution reaction (HER).
• Characterization of material properties and stability.

Main Results:

• The synthesized CoS₂-MoS₂ nanocomposite demonstrated excellent HER activity.
• Lower overpotentials of 120 mV (1 M KOH) and 153 mV (0.5 M H₂SO₄) were achieved for 10 mA cm⁻² current density.
• The nanocomposite exhibited superior chemical stability and long-term durability compared to pure MoS₂.
• Incorporation of Co²⁺ effectively increased the exposure of active sites on MoS₂.

Conclusions:

• Novel CoS₂-MoS₂ nanocomposites were successfully synthesized using POMs.
• The developed electrocatalyst shows significant potential for efficient water splitting.
• The POM-assisted strategy effectively enhances the electrocatalytic performance of MoS₂-based materials.