Aqueous Gold Nanoparticles Generated by AC and Pulse-Power-Driven Plasma Jet

Area of Science:

• Nanomaterials Science
• Plasma Physics
• Physical Chemistry

Background:

• Gold nanoparticles (AuNP) have diverse applications in catalysis, sensing, and medicine.
• Traditional AuNP synthesis methods can involve harsh chemicals and complex procedures.
• Atmospheric pressure plasma jets offer a green and efficient alternative for nanomaterial synthesis.

Purpose of the Study:

• To develop a simple, water-based synthesis for AuNPs using atmospheric pressure plasma jets.
• To compare the synthesis dynamics and resulting AuNP properties using AC-driven (A-Jet) and pulse-driven (P-Jet) plasma.
• To elucidate the roles of electrons and neutral species in the plasma-assisted AuNP formation process.

Main Methods:

• Synthesis of aqueous AuNPs using atmospheric pressure plasma jets (A-Jet and P-Jet).
• Analysis of AuNP morphology, optical emissions, and chemical reactions.
• Evaluation of electron and neutral species roles using a copper mesh.
• Measurement of chemical concentrations (Cl-, H2O2) and liquid conductivity.

Main Results:

• Visible color change indicating AuNP formation was observed in 30 s (A-Jet) vs. 3 min (P-Jet).
• A-Jet resulted in a higher AuNP growth rate and smaller AuNP diameter compared to P-Jet.
• Plasma treatment increased Cl-, H2O2 concentrations, and liquid conductivity, with greater increases under A-Jet.
• Neutral species were found to be primarily responsible for Au+ reduction, with a synergistic effect with electrons.

Conclusions:

• Atmospheric pressure plasma jets provide an efficient method for aqueous AuNP synthesis.
• A-Jet offers superior performance over P-Jet in terms of speed and AuNP size control.
• Understanding the roles of plasma species is crucial for optimizing AuNP synthesis via plasma methods.