Covalently functionalized layered MoS₂ supported Pd nanoparticles as highly active oxygen reduction electrocatalysts

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Developing efficient electrocatalysts is crucial for energy conversion devices.
• Molybdenum disulfide (MoS2) is a promising material, but its catalytic activity often requires modification.
• Palladium nanoparticles (PdNPs) are effective catalysts but can suffer from stability issues.

Purpose of the Study:

• To develop a novel hybrid electrocatalyst by immobilizing PdNPs onto functionalized MoS2 nanosheets (f-MoS2).
• To investigate the electrocatalytic activity and stability of the PdNPs/f-MoS2 hybrid for oxygen reduction reaction (ORR) in an alkaline medium.
• To understand the factors contributing to the enhanced performance of the hybrid catalyst.

Main Methods:

• Synthesis of PdNPs/f-MoS2 hybrid material using covalently modified MoS2 nanosheets.
• Characterization using Raman and IR spectroscopy, TGA, HRTEM, STEM/EELS, and EDS.
• Electrochemical evaluation of ORR activity and stability via cyclic voltammetry and chronoamperometry.

Main Results:

• The PdNPs/f-MoS2 nanohybrid demonstrated superior ORR performance with a positive onset potential (+0.066 V) and a high current response.
• The hybrid catalyst exhibited remarkable stability, with minimal activity loss over time, outperforming commercial Pd/C catalysts.
• The enhanced performance is attributed to strong PdNP-f-MoS2 affinity, absence of capping agents, and preserved MoS2 basal plane integrity.

Conclusions:

• The PdNPs/f-MoS2 hybrid electrocatalyst is highly efficient and stable for ORR in alkaline media.
• The material shows great potential for applications in fuel cells and other energy conversion technologies.
• Functionalized layered transition metal dichalcogenides offer a promising platform for advanced electrocatalyst design.