Morphology engineering of CoSe₂ as efficient electrocatalyst for water splitting.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Conversion

Background:

• Transition-metal cobalt-based chalcogenides are crucial for energy applications.
• Material morphology significantly impacts surface area and performance.
• Controlling morphology is key to optimizing catalysts for energy conversion and storage.

Purpose of the Study:

• To develop a controlled strategy for fabricating cobalt diselenide (CoSe2) with diverse morphologies.
• To investigate the application of these CoSe2 materials in water splitting.
• To correlate material morphology with electrocatalytic performance.

Main Methods:

• Facile hydrothermal synthesis of CoSe2.
• Morphology control via regulation of ammonium fluoride (NH4F) addition.
• Electrochemical characterization for water splitting (oxygen evolution reaction and hydrogen evolution reaction).

Main Results:

• Successfully synthesized CoSe2 with various morphologies: spheres, wires, and rods.
• CoSe2 spheres exhibited an urchin-like morphology with a highly hollow structure.
• This morphology resulted in a large specific surface area and efficient mass transfer channels.
• CoSe2 spheres demonstrated excellent electrocatalytic performance for oxygen evolution reaction (OER) in alkaline media and hydrogen evolution reaction (HER) in acidic media.

Conclusions:

• The urchin-like hollow CoSe2 spheres are highly effective electrocatalysts for water splitting.
• The optimized morphology enhances specific surface area and mass transport, leading to superior performance.
• CoSe2 spheres show low overpotential and superior stability, marking them as promising candidates for efficient electrocatalysts.