Release of N(2) from the carbon nanotubes via high-temperature annealing.
Nitrogen (N)-doped carbon nanotubes (CNTs) were heated to 1000 degrees C under an ultrahigh vacuum. X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure (XANES) reveal three different N structures; graphitelike, pyridine-like, and molecular N(2). The vibrationally resolved XANES peaks of N(2) were first observed, suggesting the existence of molecular N(2) as intercalated and trapped forms. The annealing process can decrease the average N content from 6.3 at. % to 3.3 at. %, mainly by releasing molecular N(2). Electron energy-loss spectroscopy (EELS) confirms that the annealing releases molecular N(2) from the CNTs.
Choi
Hyun Chul
HC
Department of Chemistry, Korea University, Jochiwon 339-700, South Korea.
Bae
Seung Yong
SY
Jang
Woo-Sung
WS
Park
Jeunghee
J
Song
Ha Jin
HJ
Shin
Hyun-Joon
HJ
Jung
Hyunsung
H
Ahn
Jae-Pyoung
JP