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 grapheneencapsulated 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.

A review of plasma-assisted catalytic conversion of gaseous carbon dioxide and methane into value-added platform chemicals and fuels

“…Further, heteroatom incorporation can be employed in order to improve the catalyst activity for applications such as oxidation, reduction, molecular abatement and reactions in fuel cells. [184][185][186] Chemical reactions between the plasma reactive species and the catalyst material create surface defects and the incorporation of heteroatoms (doping), which can in turn effectively modify the electronic band structures and surface states of the material. 167,187 Numerous other examples of chemical catalyst modi-cations using plasma can be found in literature.…”

Nitrogen and fluorine co-doped graphene as a high-performance anode material for lithium-ion batteries

“…15, 16 Reddy et al first synthesized NG on large copper current collector substrates by a liquid phase chemical vapor deposition technique directly and the synthesized NG exhibited excellent electrochemical performances as the anode of LIBs. [18][19][20] However, these methods are hardly to be used widely due to the rigorous conditions, complicated equipment, low-yields, high-cost and the toxic nitrogen precursors, such as pyridine or ammonia. [18][19][20] However, these methods are hardly to be used widely due to the rigorous conditions, complicated equipment, low-yields, high-cost and the toxic nitrogen precursors, such as pyridine or ammonia.…”

Simultaneous Pt deposition and nitrogen doping of graphene as efficient and durable electrocatalysts for methanol oxidation

“…Though there are a few studies on Pt-NG catalysts, the relatively complicated multi-step fabrication procedures have limited the large-scale catalyst synthesis [19]. Previously, the main strategy to the synthesis of Pt-NG is the two-step reaction: doping graphene with nitrogen first by the hydrothermal treatment or high-temperature annealing with N sources followed by the subsequent reduction/deposition of Pt nanoparticles [20]; or preparing graphene supported Pt nanoparticles first followed by N doping by plasma treatment [21]. The above two-step strategies make the synthesis of the electrocatalysts complicated.…”