Synthesis of Au-Ag Bimetallic Nanoparticles Using Melastoma Malabathricum Flower Extract

 Au-Ag bimetallic nanoparticles exhibit unique optical, electronic and catalytic properties different from their monometallic counterparts. This paper reports a simple cost-effective and eco-friendly solution based phytosynthesis of Au-Ag bimetallic nanoparticles. Synthesis of bimetallic Au-Ag nanoparticles was carried out using the co-reduction of mixture of different proportions of 0.25 mM AgNO3 and 0.25 mM HAuCl4 .3H2 O solutions at 50 o C using Melastoma malabathricum flower extract. Synthesized nanoparticles were characterized using UV-Vis spectrophotometer, Field Emission Scanning Electron Microscope (FESEM) equipped with Energy Dispersive X-ray analysis (EDX) instrument and Transmission Electron Microscope (TEM). The presence of single surface plasmon resonance peak in the absorption spectra suggested the formation of alloy type Au-Ag nanoparticles. The morphology studies were carried out using micrographs taken using FESEM and TEM. TEM micrographs revealed the presence of both alloy type and core–shell type bimetallic Au-Ag nanoparticles. The elemental analysis carried out using EDX spectrum showed the presence of both Au and Ag in the synthesized bimetallic nanoparticles.