title: Fe-N bonding in a carbon nanotube-graphene complex for oxygen reduction: an XAS study.
abstract: The electronic structure study of carbon nanotube-graphene complexes has been performed using comprehensive X-ray absorption spectroscopy (XAS) at Fe L- and K-edges, along with C, N and O K-edges. The results obtained from the study of an iron-containing carbon nanotube-graphene complex (NT-G) have been compared in great detail with those of an iron-free carbon nanotube-graphene complex (pNT-G) and iron phthalocyanine (FePc). It has been confirmed that complex-like Fe(3+) in a high spin state is the major iron component in NT-G. The C and N K-edge XANES further confirmed that Fe is very likely to be bonded to N in NT-G. This Fe-N species should be the active site for enhanced oxygen reduction reaction (ORR) activity in NT-G. A unique O K-edge X-ray absorption spectroscopic feature has been observed in NT-G, which might be caused by chemisorbed O2 on the Fe-N site. Such knowledge is important for the understanding of this specific complex, and the knowledge should benefit the rational design of other carbon/metal/nitrogen-containing ORR catalysts with further improved performance.
authors: Canadian Light Source Inc, Saskatoon, Canada. jigang.zhou@lightsource.ca.
authors: Jigang
authors: J
authors: Zhou
authors: Paul N
authors: PN
authors: Duchesne
authors: Yongfeng
authors: Y
authors: Hu
authors: Jian
authors: J
authors: Wang
authors: Peng
authors: P
authors: Zhang
authors: Yanguang
authors: Y
authors: Li
authors: Tom
authors: T
authors: Regier
authors: Hongjie
authors: H
authors: Dai