IFISUR   23398
INSTITUTO DE FISICA DEL SUR
Unidad Ejecutora - UE
artículos
Título:
Visualization and functions of surface defects on carbon nanotubes created by catalytic etching
Autor/es:
WEI XIA; XIULI YIN; SHANKHAMALA KUNDU; MIGUEL SÁNCHEZ; ALEXANDER BIRKNER; CHRISTOF WÖLL; MARTIN MUHLER
Revista:
CARBON
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2011 vol. 49 p. 199 - 305
ISSN:
0008-6223
Resumen:
Surface defects were created on carbon nanotubes (CNTs) by catalytic
steam gasification or catalytic etching with iron as catalysts. The
structure and morphology of the etched CNTs were studied by transmission
electron microscopy (TEM) and scanning tunneling microscopy (STM). The
electronic structure of the etched CNTs was investigated by ultraviolet
photoelectron spectroscopy (UPS). The etched CNTs were treated by nitric
acid to obtain oxygen-containing functional groups. The amount and the
thermal stability of these groups were studied by temperature-resolved
X-ray photoelectron spectroscopy (XPS). Temperature-programmed
desorption with ammonia as a probe molecule (NH3-TPD) was
employed to investigate the interaction of the surface defects with
foreign molecules in gas phase. TEM and STM studies disclosed the
presence of surface defects especially edge planes on the etched CNTs.
Etching of CNTs led to a less pronounced p-π band than the as-is CNTs,
as evidenced by UPS studies. The XPS and NH3-TPD studies
demonstrated that the defects on the CNTs enhanced the reactivity of the
exposed surfaces allowing obtaining a higher degree of oxygen
functionalization and more active adsorption sites.