Mapping functional groups on oxidised multi-walled carbon nanotubes at the nanometre scale

Abstract

Despite voluminous research on the acid oxidation of carbon nanotubes (CNTs), there is a distinct lack of experimental results showing distributions of functional groups at the nanometre length scale. Here, functional peaks have been mapped across individual multi-walled CNTs with low-dose, monochromated electron energy-loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM). Density functional theory simulations show that the EELS features are consistent with oxygenated functional groups, most likely carboxyl moieties.

Variation of carbon coatings on the electrochemical performance of LiFePO4 cathodes for lithium ionic batteries

“…Aer deconvolution, the C 1s spectrum displayed the lower binding energy featured at 284.6 eV corresponding to C]C carbon and the higher binding energies featured at 285.9 and 288.7 eV, which were typically assigned to C-O/C-O-C and C]O arising from the residual epoxide, hydroxyl and carboxyl functional groups in asphalt. [29][30][31] In addition, the smaller L a value of SCC indicated smaller graphite crystallite size, 23 which is in accordance with the calculated results L a ¼ C(l)/(I D 1 /I G ) À1 (ref. 32 and 33) from the integrated intensities of the disorder-induced D 1 and G bands (I D 1 /I G ) in Raman spectra ( Fig.…”

Excellent Rate Performance and Cycling Stability of TiP2O7@C/Carbon Nanotubes for the Aqueous Rechargeable Lithium‐Ion Battery

“…The energy separation is 5.9 eV, corresponding to a Ti 4+ oxidation state . In Figure S1c, Supporting Information, the peak of the C 1s is fitted by four peaks, corresponding to C═C (284.7eV), C—O/C—O—C (286.9 eV), C═O (285.8 eV), and O—C═O (288.6 eV), which matched well with that previously reported …”

Effect of graphene flake size on functionalisation: quantifying reaction extent and imaging locus with single Pt atom tags

“…For example, highangle annular dark-field (HAADF)/scanning electron microscopy (STEM) has been used to study the distribution of heavy atoms complexed to graphene oxide (GO) functional groups, [6] whilst STEM-EELS (energy electron loss spectroscopy) was used to study the distribution of oxygen containing groups on carbon nanotubes. [7] Scanning probe microscopy techniques, such as scanning tunnelling microscopy (STM), can resolve defects, particularly on clean well defined SLGs, and have been used to map the distribution of both grafted organic groups and metals. [8,9] Here, we perform a systematic study of the reactivity of a range of graphene feedstocks under reductive conditions, using atomic resolution tagging to identify the patterns of functionalisation.…”