Enhanced Catalytic Activity of CuO@CuS Core-Shell Structure for Highly Efficient HER Application.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient, low-cost electrocatalysts for the hydrogen evolution reaction (HER) is crucial for clean energy applications.
• Platinum-based catalysts are effective but expensive, hindering widespread adoption of hydrogen fuel production.
• Heteroatom incorporation can modify catalyst properties like active sites, conductivity, and kinetics.

Purpose of the Study:

• To synthesize and evaluate a novel nitrogen-doped CuO@CuS (NCOS) core-shell catalyst for the HER.
• To investigate the impact of nitrogen doping on the structural and electrochemical properties of CuO@CuS catalysts.
• To assess the catalytic activity, efficiency, and stability of the NCOS catalyst compared to pure CuS.

Main Methods:

• Facile hydrothermal synthesis followed by nitrogenation to create the NCOS core-shell catalyst.
• Systematic electrochemical analysis, including overpotential, Tafel slope, and chronopotentiometric testing.
• Analysis of turnover frequency (TOF) and electrochemical impedance spectroscopy (EIS) to understand catalytic mechanisms.

Main Results:

• The NCOS catalyst exhibited a significantly reduced overpotential (55 mV) and Tafel slope (107 mV dec⁻¹) compared to pure CuS (179 mV and 201 mV dec⁻¹).
• Excellent stability was demonstrated over 50 hours of chronopotentiometric testing at various current densities.
• Enhanced electron transfer rates and increased accessible active sites were observed due to nitrogen incorporation.

Conclusions:

• Nitrogen doping effectively enhances the HER performance of CuO@CuS catalysts.
• The NCOS core-shell structure offers a promising, cost-effective alternative to precious metal catalysts for hydrogen production.
• The improved performance is attributed to enhanced electronic conductivity and structural modifications induced by nitrogen incorporation.