Abstract
Multiwall carbon nanotubes (MWCNTs, 1-3 mu M in length and 20-25 nm in diameter) were initially functionalized with a 2,2': 6'2 ''-terpyridine-chelated ruthenium(II) complex by covalent amidation. The resulting functionalized ruthenium MWCNTs (RuMWCNTs, 1-2 mu M in length and 10-20 nm in diameter) were characterized by thermogravimetric analysis, X-ray photoelectronic spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and scanning electron microscopy (SEM). Thermogravimetric experiments of RuMWCNTs show that the functional group coverage of terpyridine-rutheniun-terpyridine (tpy-Ru-tpy) is 0.7036 mmol/ 1.0 g carbon. The XPS results show N1s and Ru3d(5/5) signals, confirming the presence of tpy-Ru-tpy groups on the surface of MWCNTs. The FTIR spectra of the RuMWCNTs display the typical stretching mode of the carboxyl group (amide I) and a combination of amide N-H and C-N stretching mode (amide II). The Raman D-and G-line peak intensity ratio of RuMWCNTs (ID/IG 2.21) exceeds that of pristine MWCNTs (ID/IG 1.93), suggesting covalent bonding of tpy-Ru-tpy to MWCNTs and supporting the disruption of the graphitic integrity due to the proposed covalent functionalization. High-resolution SEM images confirm that tpy-Ru-tpy moieties are interconnected or attached as aggregated structures (100-200-nm range) on the surfaces of the carbon nanotubes after functionalization. The electrical property of RuMWCNTs depicts higher resistance (10.10 M Omega) than that of OX-MWCNTs (15.38 k Omega).