Hydrogen-assisted green synthesis of trimethyl chitosan gold nanoparticles

Gold nanoparticles (AuNPs) are arguably the most promising in terms of application among the noble metal nanoparticles. As such, researchers have dedicated a considerable amount of energy towards the synthesis of novel gold nanoparticles with different morphology and size, which in turn affect its potential application. This study synthesized novel spherical-shaped AuNPs via green reduction of gold ion in an aqueous solution of HAuCl₄.3H₂O in the presence of trimethyl chitosan as a stabilizing agent and pressurized H₂ gas as a reducing agent on an ice water. The size, morphology, chemical composition, chemical environment and optical activities were examined by scanning electron microscope (SEM), high-resolution transmission electron microscope (HR-TEM), x-ray photoelectron spectroscopy (XPS), and ultraviolet–visible spectroscopy (Uv–Visible), respectively. The average particle size of AuNPs is 37 nm while HR-TEM revealed a unique spherical morphology. The Tauc's plot calculation revealed a band gap of 5.0 eV. This unique morphology and optical local field enhancement in plasmonic nanocomposites could be suitable alternative for conducting devices and photocatalysis.