Formation of Disordered High-Entropy-Alloy Nanoparticles for Highly Efficient Hydrogen Electrocatalysis

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• High-entropy alloys (HEA) nanoparticles (NPs) show promise for electrocatalysis.
• Electrocatalytic processes like hydrogen evolution and oxidation are critical for energy technologies.

Purpose of the Study:

• Synthesize and characterize two types of quinary HEA NPs (PtRhPdIrRu) with disordered and crystallized nanostructures.
• Evaluate the electrocatalytic performance and stability of these HEA NPs in acidic electrolytes.
• Investigate their application as anodic catalysts in H2-O2 fuel cells.

Main Methods:

• Synthesis of quinary HEA NPs (PtRhPdIrRu) with disordered and crystallized nanostructures using a boiling mixture method.
• Characterization of nanoparticle size and structure.
• Electrocatalytic activity testing for hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR).
• Stability testing under constant current electrolysis.
• Performance evaluation in an H2-O2 fuel cell.

Main Results:

• Disordered HEA NPs (d-HEA NPs) synthesized under intense boiling conditions exhibited a size of 3.5 nm.
• d-HEA NPs achieved a high turnover frequency of 33.1 s⁻¹ at 50 mV overpotential, 5.4 times higher than commercial Pt NPs.
• d-HEA NPs demonstrated superior stability compared to commercial Pt NPs at 50 mA cm⁻².
• As anodic catalysts in H2-O2 fuel cells, d-HEA NPs delivered a high current power density of 15.3 kW/g noble metal.

Conclusions:

• Disordered HEA NPs possess exceptional electrocatalytic activity and stability for hydrogen-related electrochemical applications.
• The synthesis method involving intense boiling conditions enhances nanoparticle properties.
• These findings underscore the potential of d-HEA NPs as advanced catalysts in fuel cells and electrolysis.