Colloidal Syntheses of Shape- and Size-Controlled Pt Nanoparticles for Electrocatalysis

Abstract

Different colloidal synthesis methods of platinum nanoparticles with controlled sizes and shapes that are relevant for electrocatalysis studies are reviewed. Four main methods, i.e., water in oil microemulsion (w/o) method, polyacrylate (PA) method, tetradecyltrimethylammonium bromide (TTAB) method, and ethylene glycol method, are used to synthesize platinum nanoparticles. The PA method allowed us to synthesize reproducibly nanocubes, nanooctahedrons, or nanocuboctahedrons/truncated nanooctahedrons with size between 8 and 10 nm, the TTAB method led to the synthesis of nanocubes of about 10 nm, and the w/o method allowed the synthesis of spherical particles of about 3 nm. All these samples could be cleaned for further electrochemical characterization of their surface structure by hydrogen underpotential deposition and by spontaneous deposition and oxidation of bismuth and germanium, leading to a quantitative determination of the (100) and (111) surface domains. The samples prepared by the ethylene glycol method, in the presence or not of polyvinylpyrrolydone as surfactant, were size or shape controlled, but did not allow the electrochemical characterization of their surface due to remaining of strongly adsorbed organic species even after cleaning steps.