The turkevich method revisited: A comprehensive guide to molar ratio control in the synthesis of 15 nm gold nanoparticles for beginners

Abstract

This study provides a comprehensive guide for novice researchers to synthesize gold nanoparticles (AuNPs) with a target size of 15 nm using the Turkevich method. By employing a systematic approach, we successfully produced well-defined AuNPs with a moderate size distribution and spherical morphology. A step-by-step procedure flowchart of the synthesis procedure, along with equations for molar ratio calculations, is provided to assist novice researchers. A fixed molar ratio of 2.8 for the reducing agent to precursor was chosen, as previous studies indicate this ratio reliably yields nanoparticles of approximately 15 nm. Characterization techniques, including Ultra-High Resolution Scanning Electron Microscope (UHR-SEM), UV-visible spectroscopy, zeta potential measurements, and zeta sizer, were employed to confirm the desired properties. Additionally, Energy-Dispersive X-ray Spectroscopy (EDX) was utilized to verify the elemental composition of the nanoparticles, confirming the presence of pure gold and the absence of impurities. SEM analysis revealed an average particle size of 15 nm, aligning with the target size. Zeta potential measurements revealed an average value of -38.56 mV. Additionally, an average polydispersity index (PDI) of 0.367, obtained from triplicate measurements, further supports the monodisperse nature of the synthesized AuNPs. The synthesized AuNPs have potential applications in various fields, especially those requiring precisely sized particles, such as biomedicine and catalysis. Future research may focus on optimizing the synthesis process to enhance reproducibility and explore additional applications, including the production of AuNPs with different sizes by adjusting the molar ratio of reducing agent to precursors.