title: Revealing the role of catalysts in carbon nanotubes and nanofibers by scanning transmission X-ray microscopy.
abstract: The identification of effective components on the atomic scale in carbon nanomaterials which improve the performance in various applications remains outstanding challenges. Here the catalyst residues in individual carbon nanotube (CNT) and carbon nanofiber (CNF) were clearly imaged with a concurrent characterization of their electronic structure by nanoscale scanning transmission X-ray microscopy. Except for prominent catalyst nanoparticle at the tip, tiny catalyst clusters along the tube (fiber) were detected, indicating a migration of the catalysts with the growth of CNTs (CNFs). The observation provides the direct evidence on the atomic metal in CNT for oxygen reduction reported in the literature. Interaction between catalysts (Fe, Ni) and CNTs (CNFs) at the tip was also identified by comparing the X-ray absorption spectra. A deep understanding of catalyst residues such as Fe or Ni in carbon nanomaterials is very vital to growth mechanism development and practical applications.
authors.affiliation: Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Materials Laboratory (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Gao
authors.affiliation: Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Materials Laboratory (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhong
authors.affiliation: Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Materials Laboratory (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Bai
authors.affiliation: Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Materials Laboratory (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123, China.
authors.forename: Jinyin
authors.initials: J
authors.lastname: Liu
authors.affiliation: Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Materials Laboratory (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123, China.
authors.forename: Guanqi
authors.initials: G
authors.lastname: Zhao
authors.affiliation: Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Materials Laboratory (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123, China.
authors.forename: Xuhui
authors.initials: X
authors.lastname: Sun