催化作用
碳纳米管
碳纤维
材料科学
金属
氮气
形态学(生物学)
过渡金属
化学工程
兴奋剂
氧还原
氧气
比表面积
电化学
无机化学
纳米技术
化学
电极
复合材料
冶金
有机化学
物理化学
复合数
工程类
生物
遗传学
光电子学
作者
Xianliang Wang,Qing Li,Hengyu Pan,Ye Lin,Yujie Ke,Haiyang Sheng,Mark T. Swihart,Gang Wu
出处
期刊:Nanoscale
[The Royal Society of Chemistry]
日期:2015-01-01
卷期号:7 (47): 20290-20298
被引量:110
摘要
We demonstrate a new strategy for tuning the size of large-diameter and few-walled nitrogen-doped carbon nanotubes (N-CNTs) from 50 to 150 nm by varying the transition metal (TM = Fe, Co, Ni or Mn) used to catalyze graphitization of dicyandiamide. Fe yielded the largest tubes, followed by Co and Ni, while Mn produced a clot-like carbon morphology. We show that morphology is correlated with electrocatalytic activity for the oxygen reduction reaction (ORR). A clear trend of Fe > Co > Ni > Mn for the ORR catalytic activity was observed, in both alkaline media and more demanding acidic media. The Fe-derived N-CNTs exhibited the highest BET (∼870 m(2) g(-1)) and electrochemically accessible (∼450 m(2) g(-1)) surface areas and, more importantly, the highest concentration of nitrogen incorporated into the carbon planes. Thus, in addition to the intrinsic high activity of Fe-derived catalysts, the high surface area and nitrogen doping contribute to high ORR activity. This work, for the first time, demonstrates size-controlled synthesis of large-diameter N-doped carbon tube electrocatalysts by varying the metal used in N-CNT generation. Electrocatalytic activity of the Fe-derived catalyst is already the best among studied metals, due to the high intrinsic activity of possible Fe-N coordination. This work further provides a promising route to advanced Fe-N-C nonprecious metal catalysts by generating favorable morphology with more active sites and improved mass transfer.
科研通智能强力驱动
Strongly Powered by AbleSci AI