Nitrogen doped graphene prepared by hydrothermal and thermal solid state methods as catalyst supports for fuel cell

• Nitrogen-doped graphenes with similar N doping levels have been prepared.
• Used as catalyst support for methanol oxidation and oxygen reduction reactions.
• Improved catalyst utilization observed with addition of MWNT as spacer.
• Experimental data has been fitted into a semi-empirical equation.
• The effect of MWNT as spacer is more pronounced in case of single cell.

Nitrogen doped graphene has been synthesized using hydrothermal method and thermal solid state method with ammonia and melamine as nitrogen sources respectively. Platinum nanoparticles have been dispersed over these support materials using polyol method and these Pt loaded nitrogen doped graphene samples have been studied as electrocatalyst for oxygen reduction reaction (ORR) in a proton exchange membrane fuel cell and for methanol oxidation reaction (MOR). Also, the role of multiwalled carbon nanotubes as a spacer which avoids face to face agglomeration of graphene sheets has also been studied for both the samples. The morphology and structure of the graphene based powder samples have been studied using X-ray diffraction, Raman spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. Half cell and full cell measurements have been performed on the samples for ORR and MOR. With the use of functionalized multiwalled carbon nanotubes, a maximum power density of 704 mW cm−2 and 650 mW cm−2 has been obtained with Pt dispersed nitrogen doped graphenes prepared by hydrothermal and thermal solid state methods respectively. The results have been compared with commercial Pt/C catalyst.