Green Synthesis and Characterization of Alloy Nanoparticles Using Plant Extracts

The green synthesis of gold (Au), palladium (Pd), and Au-Pd bimetallic nanoparticles using Aspalathus linearis (Burm.f.) R. Dahlgren, commonly known as green rooibos, as well as its pure bioactive compound, aspalathin, involves a sustainable and environmentally friendly approach to nanoparticle fabrication.

Aspalathus linearis, commonly known as green rooibos, serves as the primary source material for this synthesis process. The extract obtained from Aspalathus linearis contains various phytochemicals, including the bioactive compound aspalathin, which plays a crucial role in nanoparticle formation.

The synthesis typically begins by preparing a solution of the Aspalathus linearis extract or a solution containing a specific concentration of aspalathin. This solution serves as both the reducing agent and stabilizing agent for the nanoparticle synthesis process.

Next, metal precursors, such as chloroauric acid (HAuCl₄) for gold nanoparticles and palladium chloride (PdCl₂) for palladium nanoparticles, are added to the solution. The aspalathin in the solution acts as a reducing agent, facilitating the reduction of metal ions to form metal nanoparticles.

Under suitable reaction conditions, such as controlled temperature and pH, the reduction of metal ions occurs, leading to the nucleation and growth of Au, Pd, or Au-Pd bimetallic nanoparticles. Aspalathin molecules present in the solution interact with the metal ions, leading to the formation of stable nanoparticles with controlled size and morphology.

The green synthesis approach offers several advantages, including:

1. Sustainability: The use of natural extracts from Aspalathus linearis reduces the reliance on chemical reagents, minimizing the environmental impact of nanoparticle synthesis.

2. Biocompatibility: Aspalathin, as a bioactive compound derived from a plant source, enhances the biocompatibility of the synthesized nanoparticles, making them suitable for various biomedical applications.

3. Scalability: The green synthesis process can be easily scaled up for large-scale production of nanoparticles without compromising environmental sustainability.

4. Cost-effectiveness: By utilizing plant extracts as reducing and stabilizing agents, the green synthesis approach offers a cost-effective alternative to conventional nanoparticle synthesis methods.

Overall, the green synthesis of Au, Pd, and Au-Pd bimetallic nanoparticles using Aspalathus linearis and aspalathin showcases a sustainable and eco-friendly strategy for nanoparticle fabrication, with promising applications in various fields, including catalysis, biomedicine, and environmental remediation.

The data provided encompasses results obtained through a variety of characterization techniques, including:

• Ultraviolet-Visible (UV-Vis) Spectroscopy

• Dynamic Light Scattering (DLS) Analysis

• High-Resolution Transmission Electron Microscopy (HRTEM)

• Selected Area Electron Diffraction (SAED)

• Scanning-Transmission Electron Microscopy with High Angle Annular Dark Field (STEM-HAADF)

• Attenuated Total Reflection-Fourier-Transform Infrared Spectroscopy (ATR-FTIR)

These techniques collectively offer comprehensive insights into the properties and structure of the materials under the study.

Note: The study did not require ethical clearance