Plasma-assisted nitrogen doping of graphene-encapsulated Pt nanocrystals as efficient fuel cell catalysts

Abstract

We have synthesized a nanostructure with a platinum (Pt) nanocrystal core and a few-layer graphene shell. This graphene-encapsulated Pt nanocrystal (GPN) was fabricated through a simple chemical vapor deposition (CVD) method. After investigating the electrocatalytic activities of GPNs, their ability to act as a relatively good fuel cell catalyst was confirmed. Furthermore, to further improve their catalytic activity, a plasma-assisted nitrogen doping method was developed, and the nitrogen-doped graphene-encapsulated Pt nanocrystal (N-GPN) also demonstrated efficient electroactivities, in fact much higher than those reported for conventional Pt–graphene composite catalysts due to their small particle diameter, uniform size distribution, sufficient graphene–Pt contact, and new generation of activation sites after nitrogen doping. This simple and efficient approach could also be extended to the preparation of other alloy nanocrystals coated with a graphene shell for electrocatalytic or electrochemical sensor applications.