Influence of Ethylene Thermal Decomposition on Carbon Nanotube Growth: Insights from a Two-Zone Reactor Study

Abstract

Gas-phase decomposition of carbon precursor is a critical yet not fully understood step in the catalytic chemical vapor deposition growth of carbon nanotubes (CNTs). Here, we present a systematic investigation of how the thermal decomposition of C2H4 influences CNT growth. Using a custom-designed two-zone reactor with independently controlled preheating (decomposition) and CNT growth zones, we decoupled the effects of gas-phase decomposition from the growth temperature. A standard synthesis condition was first established using Bayesian Optimization, with the CNT growth zone temperature (Tg) fixed at 700 °C. CNTs were then synthesized at preheating zone temperature (Tp) of 500, 600, 700, 800, and 900 °C, while maintaining Tg at 700 °C under the standard condition. Carbon yield and IG/ID remained stable at 500, 600, and 700 °C but showed significant changes at 800 and 900 °C. To elucidate these variations, we analyzed the gas-phase composition at various temperatures using micro-GC. Significant change in the gas-phase composition was observed at above 700 °C, correlating with changes in carbon yield and crystallinity. Based on these results, we propose a mechanism by which differences in gas chemistry lead to changes in the carbon yield and the IG/ID ratio. This study provides valuable insight into the role of gas-phase decomposition in CNT growth and highlights the potential of tuning gas-phase chemistry for controlled growth of CNTs.

Supplementary files

Article information

Article type
Paper
Submitted
21 Cax 2025
Accepted
14 Qad 2025
First published
18 Qad 2025
This article is Open Access
Creative Commons BY-NC license

Nanoscale, 2025, Accepted Manuscript

Influence of Ethylene Thermal Decomposition on Carbon Nanotube Growth: Insights from a Two-Zone Reactor Study

S. Shin, H. Jeong, J. Kim, B. J. Kim, J. H. Lee, S. Jung and J. Lee, Nanoscale, 2025, Accepted Manuscript , DOI: 10.1039/D5NR02143J

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