278042 Microfluidic Synthesis of Electro-Catalytically Active Nanoparticles
Metallic nanoparticles, owing to their exceptional properties have gained a lot of research interest. Potential applications of these nanoparticles are well known in catalysis, pigments, electronic and magnetic materials, and drug delivery. Recent advances in colloidal synthesis methods have enabled us to synthesize nanoparticles of various shapes and sizes. However the conventional batch processes give a broad size distribution because of poor mixing and temperature fluctuations. Consequently, they require further size classification step to obtain uniform particles. In our laboratory these materials are being synthesized by using microfluidic reactors which offer rapid mixing and heat transfer effects resulting in precise size control. Development of high pressure and high temperature micro-reactor techniques has provided us with unique capability of synthesizing metallic/bimetallic nanoparticles in a fast, continuous fashion with enhanced homogeneity and monodispersity along with enabling special synthesis conditions such as segmented gas liquid flow.
In this work, we demonstrate the use of microfluidics for the continuous synthesis of Pt nanodendrites (Pt-ND) and the effect of synthesis parameters on the electrocatalytic activity of the Pt-ND. Our results indicate that the synthesized Pt-ND are much more active as compared to Pt-black obtained from Sigma Aldrich, as indicated in by the cyclic voltammetry curve (Fig 1 (a), potential wrt standard Ag/AgCl electrode) even though the amount of Pt-ND loading used is approximately one tenth of Pt-black. We attribute the effect to dendritic structure (Fig 1 (b)) giving high surface area of the active sites for the reaction. We discuss the detailed synthesis method, electrocatalytic and TEM characterizations in order to understand the effect of synthesis parameters on the electrocatalytic activity of Pt-ND.
Figure 1: (a) Electrocatalytic activity of synthesized Pt-ND wrt to Pt-black, (b) HRTEM of Pt-ND