Correlation between the Electrochemical Durability of Pt/C Catalysts and the Surface Functional Groups of the Support Carbon

Abstract

Herein, we report the effects of the catalyst support surface chemical/physical state of commercially available high-surface-area carbons on the electrochemical performance of Pt/C electrocatalysts synthesized using carbons as the support for platinum nanoparticles (Pt-NPs). A series of Pt/C electrocatalysts were synthesized through a microwave-assisted polyol process. The support carbons and the Pt/C catalysts were characterized for their structural characteristics including crystallinity, microstructure (morphology and particle size distribution), physical surface area, porosity, thermal behavior, and surface chemical state. Evaluation of the electrocatalytic performances and durability parameters of the Pt/C catalysts was performed through cyclic voltammetry and an accelerated stress test (AST). The results showed that the support carbons have similar physical properties except for the amounts and types of oxygen-containing surface functional groups. The Pt/C catalysts supported on the carbon with a higher surface oxygen content were found more durable during the AST, as compared to their corresponding counterparts supported on the carbon with a lower surface oxygen content. This was attributed to the presence of oxygen functional groups that may function as the active sites for the nucleation of new Pt-NPs, hence inhibiting Ostwald ripening to some extent. This study provides valuable catalyst support selection criteria and synthesis parameters at different pressures.