Influence of sodium and calcium contaminant in the growth of carbon nanotube on rayon-based carbon fibers

Author(s)

Escanio, Camila Alves ; Antunes, Erica Freire ; Trava-Airoldi, Vladimir Jesus ; Corat, Evaldo Jose

• Document type: Journal article
• Source: MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS; v. 287, p. 11-pg., 2023-01-01.

Abstract

This study investigated the role of contaminants commonly found on rayon-based carbon fibers (CF) for the carbon nanotubes (CNT) synthesis. The most common contaminant found on CF is sodium. From the experi-mental results, sodium contaminant indeed performed as a catalyst, but with low efficiency. However, some CF samples also contained calcium as a contaminant, and Ca presence made higher density and better-quality CNT growth. Probably Ca acts as the reducing agent, keeping Na in metallic form along the entire growth process. XPS data suggests a new view of sodium oxide/hydroxide to sodium carbonate transition after CNT synthesis. On CF samples with calcium, sodium keeps activity and carbonate does not form, differently of the sample containing just Na. CF free of contaminants (PAN-based CF) helps set apart the effects and Raman Spectroscopy picked up sodium and calcium effects on the CNT crystalline quality. The sodium presence in rayon-based CF worsens CNT quality when growing from the foreign iron-cobalt catalyst. By another hand, calcium presence helps keeping iron-cobalt nanoparticles surface reduced. Images of Field Emission Gun Scanning Electron Microscopy (FEG-SEM), Energy Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD) also supported the analysis. (AU)

• FAPESP's process: 19/08473-1 - Development of carbon nanotubes supercapacitors for applications in lead-acid battery
• Grantee: Camila Alves Escanio
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 19/18572-7 - New carbon materials: their relevant space, environmental and relevant spin off applications
• Grantee: Evaldo Jose Corat
• Support Opportunities: Research Projects - Thematic Grants