Kinetic Studies of Gold Nanoparticles Formation in the Batch and in the Flow Microreactor System

In this study, synthesis of gold nanoparticles (Au NP’s) in the batch and flow reacting systems was carried out either in the presence or in the absence of PVA (polyvinyl alcohol) used as stabilizing agent. As the reductant of gold(III) chloride complex ions, the ascorbic acid was used. To determine the rate equation of the reduction process, the kinetic measurments based on spectrophotometry UV-Vis and DLS were carried out. Consequently, the rate equations of gold(III) complex ions reduction and Au NP’s formation were determined. To synthesize gold nanoparticles in the flow microreactor system the cartridge with T–type geometry of microchannels was used. Next, to calculate the parameters of the flow which enable precipitation of the gold clusters, obtained kinetic equations were applied. This type of microreactor, as well as different reagents flow rates, gave us the chance to inject Au NP’s stabilizer (PVA) at the proper instant of time. It was found that applied method is promising one for the preparation of gold nanoparticles with well defined shape (spheres) and with narrow size distribution (98 % of the Au NP’s with diameter ranged from 1 to 3 nm). Morphology of obtained Au NP’s was characterized using DLS and TEM.