Active area and particle size of Pt particles synthesized from (NH4)2PtCl6 on a carbon support

Ammonium hexachloroplatinate (AHCP, (NH4)2PtCl6) is used for the synthesis of Pt/C, which can be used as catalyst in the production of proton exchange membrane fuel cells (PEMFCʹs). AHCP is used because of its low temperature of decomposition and its high aqueous solubility at room temperature. In this work, high-resolution transmission electron microscopy (HRTEM) was used to characterize the size and distribution of the Pt particles, obtained from AHCP on a carbon support by a new preparation method. HRTEM showed an excellent dispersion of Pt particles between 2 and 4 nm. The electrochemical properties of the Pt/C catalyst were determined by means of ex situ cyclic voltammetry, which showed an electrochemically active area high enough for fuel cell electrodes. Comparison of the active area calculated from HRTEM and cyclic voltammetry showed little differences resulting in particle sizes of similar magnitude between the two techniques.