Researchers at the Korean Institute of Energy Research (KIER) and the University of Oxford in the UK showed that encapsulating platinum nanoparticles with nitrogen-doped graphene layers improves the catalytic activity of the particles, while making them more resistant to degradation. This could lead to better proton exchange membrane fuel cells (PEMFCs) in the future.
The scientists state that without the nitrogen treatment, the Pt–graphene nanoparticle is very resilient to degradation, but it also becomes a rather ineffective catalyst. The nitrogen treatment appears to 'puncture' the graphene shell, allowing the Pt underneath to catalyze reactions while being protected from the acidic electrolyte in a fuel cell. The researchers found that the porous graphene encapsulated Pt nanoparticles were almost as good as bare Pt nanoparticles in terms of catalytic performance (with a peak efficiency of 87% compared to bare Pt) but that they did not degrade compared to the bare particles.
The team aims to further improve the catalysts it fabricated to make them even more resistant to degradation. The scientists are already working on developing a CVD system for synthesizing metal–graphene hybrid materials in large quantities, with a view to commercializing these catalysts.