Attachment of platinum nanoparticles to substrates by coating and polyol reduction of a platinum precursor

Abstract

Metal nanoparticles with good adhesion to substrates are important in practical applications, such as in catalysis, but directly depositing metal nanoparticles on substrates with good adhesion from a solution of their precursors has been rarely explored. This work reports a two-step method to deposit catalytic platinum (Pt) nanoparticles with good adhesion to substrates by solution processing and chemical reduction of a Pt precursor at a relatively low temperature. The first step is to coat a layer of H2PtCl 6 on a substrate, such as fluorine-doped tin oxide (FTO), indium tin oxide (ITO), or conductive poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS). The second step is to cast ethylene glycol (EG) on the H2PtCl6 layer and convert H 2PtCl6 into metallic Pt nanoparticles by heating at 160 ° for a few minutes. The Pt nanoparticles join together into a continuous Pt nanoparticle structure that is different from the dendritic structure and has good adhesion to substrates. The good adhesion of the Pt nanoparticles to the substrates is attributed to the deposition of the Pt nanoparticles with high surface energy and the disappearance of EG shortly after the nanoparticle formation. The Pt nanoparticles cannot be removed from the substrates by adhesive tape peeling or sonication. The continuous Pt nanoparticle strutures can be used as the catalyst for many energy-conversion electrochemical reactions, such as oxidation of methanol and reduction of triiodide. They were also used as the counter electrode of dye-sensitized solar cells (DSCs). The DSCs exhibited light-to-electricity conversion efficiency of 8.02% under AM1.5G illumination (100 mW cm-2) and good stability. © 2011 American Chemical Society.