Preparation of Pt/C via a polyol process – Investigation on carbon support adding sequence

To investigate the effect of carbon support adding sequence on Pt particle sizes and Pt utilizations during the polyol process of the electrocatalyst preparation, a series of Pt/C electrocatalysts (different Pt loadings, two kinds of carbon supports−Vulcan XC and Black Pearls 2000) were prepared, namely, Pt/C-a (first reduced Pt ions to form Pt nanoparticles, which subsequently deposited on carbon supports) and Pt/C-b (Pt precursors were first impregnated with carbon supports, then reduced to Pt nanoparticles). The physical properties of the electrocatalysts were characterized by X-ray diffraction, transmission electron microscopy and nitrogen adsorption. The catalytic activities of the electrocatalysts toward the oxygen reduction reaction and the methanol oxidation reaction were characterized by potentiodynamic measurements. The results show that the carbon support adding sequence has significant effects on the Pt particle sizes, especially for the carbon supports with large amount of micropores, as a result, leading to different catalytic activities.

► Carbon support adding sequence influences the Pt particle sizes and utilizations. ► Route A produced smaller Pt particles compared to Route B. ► The surface chemistry influences the nuclear-formation and growth of Pt particles. ► The adding sequence of supports significantly affects the catalytic activity of Pt/C.