Oxygen Reduction reaction (ORR) on Pt nanoparticles (NPs) dispersed on carbon has been widely studied, however, improvement in catalyst durability and cost reduction are two major obstacles yet to overcome for the popularization of fuel cell vehicles. Various approaches have been focused upon either to tailor the NPs itself or the carbon support. This work deals with the effect of surface modification of Pt nanoparticles (NPs) on ORR activity using organic perflourinated alkylamine (UFHA: undecafluorohexylamine) and alkylamine (OA: octylamine). Alkylamines are used as surfactants for nanoparticles since they are adsorbed weakly on the surface allowing reactants to access the NP surface easily. The modified Pt NPs (OA/UFHA-Pt/CB and OA-Pt/CB) were well characterized and studied for their ORR activity and performance. Comparable electrochemical active surface area (ECSA) values and high mass and area specific activities were obtained for the synthesized catalysts compared to those of the commercial 30%Pt/CB (carbon black: Vulcan XC-72) (Fig. 1a). The ORR activity was explained mechanistically (Fig. 1b). Perfluorinated alkyl chain of UFHA is hydrophobic which promotes proton conduction path formation from the electrolyte to the Pt surface. The perflourinated alkylamines also acted as corrosion inhibitor during an accelerated durability potential cycle test. The strategy demonstrates a precise coating approach for designing the hyperactive electrocatalyst with improved catalyst activity and durability.

Perflourinated alkylamine modified Pt nanoparticles as hyperactive ORR electrocatalyst for fuel cell application

254th National Meeting (2017)

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