Synthesis and application of metal and metal oxide nanoparticles

Abstract

Nanomaterials with diameters in the range of 1~20 nm have been extensively stu-died over the last decade. The small dimensions of these materials, so-called ‘nanoparticles’, result in different chemical and physical properties from those observed in the cor-responding macro-crystalline, ‘bulk’ materials. In this paper, we introduce ‘Tin-doped In-dium Oxide (ITO)’ nanoparticles and their optical properties which controlled by the vari-ous sizes with variable tin content. We also prepare the morphology controlled PtCo nano-crystals and the application for catalytic activity toward oxygen reduction reaction (ORR) of polymer-exchange-membrane fuel cells (PEMFCs). In part 2, we present synthesis and characterization of ITO nanoparticles, as well as their optical properties. The size and metal composition controlled ITO nanoparticles are easily obtained by colloidal system, which is composed of isolated particles with stabilizing by surfactant molecules and dispersed in solvent media. The optical properties of the ITO nanoparticles were analyzed with photoluminescence (PL) spectroscopy, and those results reveal that the exciton Bohr diameter is around 7-9 nm and the PL emission maxima are blue-shifted as the particle size decreases and the Sn content increases. We introduce synthesis of Pt9Co nanocubes (NCs) with significantly enhanced ORR activity in part 3. Recent reports reveal that the Pt-based bimetallic particles and the Pt par-ticles with controlled surface arrangement have shown enhanced ORR activity than pure Pt particles. In these regards, we herein report the Pt9Co NCs dominantly bound by {100} planes and the catalytic activity of the Pt9Co NCs in H2SO4 media. The onset potential of the Pt9Co NCs has a more positive value than those of the other catalysts and the current density at half-wave potential of the Pt9Co NCs is about 4, 1.6, and 1.9 times higher than that of the commercial Pt/C catalyst, the spherical Pt9Co, and the cubic Pt NCs. In part 4, ...