Highly dispersed Pt/C catalysts prepared by the Charge Enhanced Dry Impregnation method

• Adsorption of Pt precursors on carbon is maximized via the slurry pH (SEA method).
• Maximum adsorption conditions can be combined with dry impregnation (CEDI method).
• CEDI was used for the preparation of Pt/carbon xerogel catalysts.
• Catalysts with 10 wt.% mass fraction and particle size ca. 2 nm were obtained.
• Catalysts prepared via the CEDI or SEA method feature identical ORR activity.

An efficient method to synthesize highly dispersed Pt/carbon xerogel catalysts for Proton Exchange Membrane fuel cell applications is described. The synthesis proceeds via the Charge Enhanced Dry Impregnation method (CEDI), which combines dry impregnation with the Strong Electrostatic Adsorption technique (SEA). The samples prepared via CEDI or SEA techniques were dried and reduced under hydrogen to obtain supported Pt nanoparticles. In order to increase the Pt mass fraction up to 10 wt.%, two successive impregnation-drying-reduction cycles were performed. The synthesized Pt nanoparticles are homogeneously distributed on the carbon support and highly dispersed (mean Pt nanoparticle size of ca. 2 nm). The CEDI method is ideally suited to avoid Pt losses during the catalyst preparation.

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