Role of Hydrogen in Ethylene-Based Synthesis of Single-Walled Carbon Nanotubes

• Published in: Nanomaterials (Basel, Switzerland) Vol. 13; no. 9; p. 1504
• Main Authors: Bogdanova, Alisa R, Krasnikov, Dmitry V, Khabushev, Eldar M, Ramirez B, Javier A, Matyushkin, Yakov E, Nasibulin, Albert G
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 28-04-2023; MDPI
• Subjects: Aerosols; Analysis; Carbon; Carbon sources; Catalysts; Chemical synthesis; Chemical vapor deposition; Cleaning; Electron microscopy; Etching; Ethylene; Glass substrates; Hydrogen; Identification and classification; Low concentrations; Methods; Nanotechnology; Nanotubes; Properties; Pyrolysis; Raman spectroscopy; Scanning electron microscopy; Scanning microscopy; Single wall carbon nanotubes; single-walled carbon nanotubes; Spectrum analysis; Synthesis; Thin films; Transmission electron microscopy; Russia; pyrolysis; hydrogen; ethylene; chemical vapor deposition; single-walled carbon nanotubes
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano13091504

We examined the effect of hydrogen on the growth of single-walled carbon nanotubes in the aerosol (a specific case of the floating catalyst) chemical vapor deposition process using ethylene as a carbon source and ferrocene as a precursor for a Fe-based catalyst. With a comprehensive set of physical methods (UV-vis-NIR and Raman spectroscopies, transmission electron microscopy, scanning electron microscopy, differential mobility analysis, and four-probe sheet resistance measurements), we showed hydrogen to inhibit ethylene pyrolysis extending the window of synthesis parameters. Moreover, the detailed study at different temperatures allowed us to distinguish three different regimes for the hydrogen effect: pyrolysis suppression at low concentrations (I) followed by surface cleaning/activation promotion (II), and surface blockage/nanotube etching (III) at the highest concentrations. We believe that such a detailed study will help to reveal the complex role of hydrogen and contribute toward the synthesis of single-walled carbon nanotubes with detailed characteristics.