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Shape Control of Mn 3 O 4 Nanoparticles on Nitrogen‐Doped Graphene for Enhanced Oxygen Reduction Activity
Author(s) -
Duan Jingjing,
Chen Sheng,
Dai Sheng,
Qiao Shi Zhang
Publication year - 2014
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201302940
Subject(s) - graphene , materials science , nanoparticle , doping , nitrogen , catalysis , nanotechnology , chemical engineering , metal , phase (matter) , mesoporous material , metallurgy , organic chemistry , optoelectronics , engineering , chemistry
Three kinds of Mn 3 O 4 nanoparticles with different shapes (spheres, cubes, and ellipsoids) are selectively grown on nitrogen‐doped graphene sheets through a two‐step liquid‐phase procedure. These non‐precious hybrid materials display an excellent ORR activity and good durability. The mesoporous microstructure, nitrogen doping, and strong bonding between metal species and doped graphene are found to facilitate the ORR catalytic process. Among these three kinds of Mn 3 O 4 particles, the ellipsoidal particles on nitrogen‐doped graphene exhibit the highest ORR activity with a more positive onset‐potential of –0.13 V (close to that of Pt/C, –0.09 V) and a higher kinetic limiting current density ( J K ) of 11.69 mA cm –2 at –0.60 V. It is found that the ORR performance of hybrid materials can be correlated to the shape of Mn 3 O 4 nanocrystals, and specifically to the exposed crystalline facets associated with a given shape. The shape dependence of Mn 3 O 4 nanoparticles integrated with nitrogen‐doped graphene on the ORR performance, reported here for the first time, may advance the development of fuel cells and metal‐air batteries.