Rational Design and Synthesis of Extremely Efficient Macroporous CoSe₂ -CNT Composite Microspheres for Hydrogen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts for the hydrogen evolution reaction (HER) is crucial for renewable energy technologies.
• Cobalt diselenide (CoSe2) shows promise as an HER catalyst, but its performance can be limited by conductivity and morphology.
• Carbon nanotubes (CNTs) offer excellent electrical conductivity and structural support.

Purpose of the Study:

• To synthesize and characterize novel CoSe2-CNT composite microspheres for improved HER performance.
• To investigate the effect of CNTs on the morphology, conductivity, and catalytic activity of CoSe2.
• To evaluate the electrocatalytic activity of the composite material in an acidic medium.

Main Methods:

• Spray pyrolysis and subsequent selenization were employed to create CoSe2-CNT composite microspheres.
• The morphology and composition of the synthesized materials were analyzed.
• Electrochemical testing, including polarization curves and Tafel slope analysis, was performed to assess HER activity.

Main Results:

• The CoSe2-CNT composite microspheres exhibited ultrafine CoSe2 nanocrystals uniformly decorating a macroporous CNT backbone.
• The composite material demonstrated excellent HER catalytic activity, achieving 10 mA cm-2 at an overpotential of approximately 174 mV.
• Compared to bare CoSe2 powders (overpotential of 226 mV), the CoSe2-CNT composites showed significantly enhanced performance with a Tafel slope of 37.8 mV dec-1.

Conclusions:

• The macroporous CNT backbone effectively enhances the electrical conductivity and catalytic activity of CoSe2 for HER.
• The unique microsphere structure facilitates efficient H2 removal and minimizes electrode polarization, leading to superior electrocatalytic performance.
• CoSe2-CNT composite microspheres represent a promising advanced catalyst for the hydrogen evolution reaction.