Surface Engineering of Multi-Walled Carbon Nanotubes via Ion-Beam Doping: Pyridinic and Pyrrolic Nitrogen Defect Formation

Abstract

In this study, we present an innovative ion-beam doping technique for the controlled modification of the near-surface region of multi-walled carbon nanotubes (MWCNTs) aimed at creating pyridinic and pyrrolic nitrogen defects in their walls. This method involves the irradiation of MWCNTs with nitrogen ions using a high-dose ion implanter, resulting in the incorporation of nitrogen atoms into the nanotube structure. The structural and chemical changes induced by the ion-beam treatment were thoroughly characterized. Scanning electron microscopy (SEM) analysis revealed subtle changes in nanotube morphology, while X-ray diffraction (XRD) measurements exhibited altered peak intensities and a shift in the (002) reflection peak, indicating structural modifications, which correlates with transmission electron microscopy (TEM) data. X-ray photoelectron spectroscopy (XPS) analysis confirmed the successful embedding of nitrogen, mainly in pyridinic and pyrrolic configurations, as evidenced by the presence of corresponding lines in the N1s spectrum. Our findings demonstrate the feasibility of precisely engineering nitrogen defects in MWCNTs using the ion-beam doping technique. This approach is expected to be promising for the use of carbon nanotubes surface-functionalized with nitrogen atoms in the development of new devices for electronics, electrochemistry, catalysis, etc.

Improving the Adhesion of Multi-Walled Carbon Nanotubes to Titanium by Irradiating the Interface with He+ Ions: Atomic Force Microscopy and X-ray Photoelectron Spectroscopy Study

“…Figure 4 shows the C 1s PE spectra of “MWCNT/Ti” before and after ion treatment. The spectrum of the sample before irradiation ( Figure 4 a) contains five components that correspond to graphite-like sp 2 carbon C=C (~284.6 eV, C1), sp 3 carbon C–C in diamond and/or carbon located near oxygen-containing functional groups [C*–C(O)] (~285.5 eV, C2), carbon in the C–O (~286.4 eV, C3) and C=O (~287.5 eV, C4) groups, as well as carbon in the COOH– groups (~289 eV, C5) [ 24 , 25 , 26 ]. The high-energy maximum sh (~291 eV) represents a satellite, which is typical for C 1s PE spectra of sp 2 carbon atoms in systems with a high degree of graphitization and is associated with the π→π* shake-up process occurring simultaneously with C 1s photoionization [ 25 ].…”

“…carbon C-C in diamond and/or carbon located near oxygen-containing functional groups [C*-C(O)] (~285.5 eV, C2), carbon in the C-O (~286.4 eV, C3) and C=O (~287.5 eV, C4) groups, as well as carbon in the COOH-groups (~289 eV, C5)[24][25][26]. The high-energy maximum sh (~291 eV) represents a satellite, which is typical for C 1s PE spectra of sp 2 carbon atoms in systems with a high degree of graphitization and is associated with the π→π* shake-up process occurring simultaneously with C 1s photoionization[25].…”

Atomic and Electronic Structure of Metal–Salen Complexes [M(Salen)], Their Polymers and Composites Based on Them with Carbon Nanostructures: Review of X-ray Spectroscopy Studies

“…XPS is a widely used X-ray spectroscopic method for studying the characteristics of the filled inner (core) electron shells of atoms in solid, adsorbed, and gas-phase polyatomic systems [117][118][119]. Core-level photoemission spectra are used to measure the binding energy (E bin ) of the core electrons of atoms and their energy differences (chemical shifts) in various compounds.…”