Rapid and efficient synthesis of colloidal gold nanoparticles by arc discharge method

We report a simple, inexpensive and one-step synthesis route of colloidal gold nanoparticles using arc discharge between titanium electrodes in HAuCl4 solution achieving long-time stability. Gold nanoparticles of 8 nm diameter were formed during reduction of HAuCl4 in the plasma discharge zone. The resulting nanoparticles were characterized using UV-Vis spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Optical absorption spectroscopy of as prepared samples at 15 A arc current in HAuCl4 solution shows a surface plasmon resonance around 550 nm. It was found that sodium citrate acts as a stabilizer and surface capping agent of the colloidal nanoparticles. SEM images exhibit the increase of reduced nanoparticles in 4 minutes arc duration compared with 1 minute arc duration. A TEM image of the sample prepared at 4 minutes arc duration shows a narrow size distribution with 8 nm mean particle size. The plasmonic peak intensity of as prepared gold nanoparticles in 1 minute arc duration gradually increases due to seed mediation up to 6 hours.