Biosynthesis of Silver and Gold Nanoparticles Using Huangdan (Camellia sinensis) Leaf Extract

The biosynthesis of nanoparticles is in the limelight of modern nanotechnology. Biogenic Ag and Au nanoparticles were synthesized by a rapid and simple procedure using leaves extract of tea as the reducing agent. The formations of Ag and Au nanoparticles were monitored using the UV-visible spectra as a function of the reaction time and the formation process, which determined that the optimal reaction time of Ag+ and Au3+ ions was 4 and 1 h, respectively. The as-synthesized Ag (53.2 +/- 7.1 nm) and Au (31.7 +/- 5.2 nm) nanoparticles were characterized by transmission electron microscopy, Fourier transform infrared spectra, and thermogravimetric analysis. The X-ray diffraction spectra showed that the Ag nanoparticle was composed of two nanocrystals, while the Au nanoparticle included one nanocrystal. This rapid biosynthesis approach can be described as a green technology because of no additional chemical reagents as stabilizers or reductants.