Study of Growth Kinetics of Ultra-Long Carbon Nanotube Arrays through Wall Number Statistical Investigation

Abstract

AbstractThe unique properties of carbon nanotubes (CNTs) strongly depend on their structures. In this study, the growth kinetics of ultra-long multi-walled CNT (MWCNT) arrays by water-assisted chemical vapor deposition (WACVD) has been investigated based on the statistical studies of CNT wall number. It was found that the kinetics of MWCNT arrays in WACVD demonstrated a lengthening and thickening growth. In the linear lengthening stage, CNT wall number remains constant and catalysts preserve the activity; while in the thickening stage, CNTs thicken substantially through the gas phase-induced thickening process and catalysts start to deactivate. The effects of ethylene and hydrogen flow rates on the MWCNT array growth have also been studied. It was found that by changing ethylene flow rate, different linear lengthening stages corresponding to different CNT wall numbers could be obtained. These findings provide experimental solutions to fabrication MWCNT arrays with both selective heights and controllable wall numbers by WACVD.