Shape Control of Mn 3 O 4 Nanoparticles on Nitrogen- Doped Graphene for Enhanced Oxygen Reduction Activity
Shape Control of Mn 3 O 4 Nanoparticles on Nitrogen- Doped Graphene for Enhanced Oxygen Reduction Activity
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DOI：
10.1002/adfm.201302940
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发表时间：
2014-04-01
影响因子：
19
通讯作者：
Qiao, Shi Zhang
中科院分区：
文献类型：
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作者：
Duan, Jingjing;Chen, Sheng;Qiao, Shi Zhang
通过两步液相法，在氮掺杂的石墨烯片上选择性地生长出三种不同形状的Mn3O4纳米颗粒（球体、立方体和椭球体）。这些非贵重杂化材料表现出优异的ORR活性和良好的耐久性。介孔结构、氮掺杂以及金属与掺杂石墨烯之间的强键合有利于ORR催化过程。在这三种Mn3O4颗粒中，氮掺杂石墨烯上的椭球状颗粒表现出最高的ORR活性，具有更高的正启动电位-0.13 V（接近Pt/C的-0.09 V），在-0.60 V时具有更高的动力学极限电流密度（J(K)） 11.69 mA cm（-2）。研究发现，杂化材料的ORR性能与Mn3O4纳米晶体的形状有关，特别是与给定形状相关的暴露晶面有关。本文首次报道了掺杂氮石墨烯的Mn3O4纳米颗粒对ORR性能的形状依赖性，这可能会推动燃料电池和金属-空气电池的发展。
Three kinds of Mn3O4 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 Mn3O4 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 Mn3O4 nanocrystals, and specifically to the exposed crystalline facets associated with a given shape. The shape dependence of Mn3O4 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.