Non-uniform nitrogen doped carbon nanosheet anchored platinum nanoparticles with high oxygen reduction reaction activity

Abstract

High oxygen reduction reaction (ORR) activity and stability of cathode catalyst is one of key issues to obtain high performance proton-exchange membrane fuel cells. The most successful ORR catalysts are Pt/C based composites for their stable ORR activity in acidic electrolyte in practical application. Heteroatoms doped carbon materials especially nitrogen doped carbon supports for Pt are found to be highly effective in improving ORR activity of Pt/C based catalysts. However, research on distribution of doped nitrogen in carbon materials and its influence on ORR activity and stability is rare. In this work, we report a nitrogen doped carbon nanosheet (NC) with non-uniform distribution of doped nitrogen. Nitrogen enriched microporous regions are found to be favorable for selective anchoring Pt nanoparticles by the strong PtN interaction. The influence of non-uniform doped nitrogen on ORR activity and stability of Pt/NC catalysts via statistical analysis changes of Pt nanoparticles' size and their distribution before and after accelerated durability test (ADT) is carried out. It is found that NC with appropriate non-uniform doped nitrogen can well tune disperse anchoring of Pt nanoparticles and their size on NC surface and effectively improving and stabilizing activity of Pt in acidic electrolyte environment than commercial Pt/C catalyst.