Preparation of PtNi Nanoparticles for the Electrocatalytic Oxidation of Methanol

heating which are conducive to homogenous nucleation and a shorter crystallization time [14]-[16]; factors which are generally believed to be the prerequisite to the formation of monodisperse nanoparticles. Furthermore, microwave heating has also been found to increase reaction kinetics by one to two orders of magnitude [16]-[18]. Thus microwave assisted synthesis could pave way for the preparation of highly effective catalytic nanoparticles where the high surface-to-volume ratio of the particles can substantially reduce the loading of the cost-bearing active Abstract — Carbon supported PtNi nanoparticles were prepared by hydrazine reduction of Pt and Ni precursor salts under different conditions, namely by conventional heating (PtNi-1), by prolonged reaction at room temperature (PtNi-2) and by microwave assisted reduction (PtNi-3). The nanocomposites were characterized by XRD, EDX, XPS and TEM and used as electrocatalysts in direct methanol fuel cell (DMFC) reactions. Investigations into the mechanism of PtNi nanoparticle formation revealed that platinum nanoparticle seeding was essential for the formation of the bimetallic nanoparticles. The average particle size of PtNi prepared by microwave irradiation was the lowest, in the range of 2.9 – 5.8 nm. The relative rates of electrooxidation of methanol at room temperature as measured by cyclic voltammetry showed an inverse relationship between catalytic activity and particle size in the following order PtNi-1 < PtNi-2 < PtNi-3. components.