Purity-controllable growth of bamboo-like multi-walled carbon nanotubes over copper-based catalysts

Abstract

Abstract The growth of bamboo-like multi-walled carbon nanotubes (CNTs) without the formation of amorphous carbons was performed using copper-based catalysts by catalytic chemical vapour deposition (CVD) with diluted ethylene at 700–900 °C. The as-grown CNT soot was characterised by transmission electron microscopy, thermogravimetric analysis and Raman spectroscopy. The weak metal–support interaction of a sulphate-assisted copper catalyst (CuSO 4 /SiO 2 ) can provide high-purity growth with remarkable yields of CNTs (2.24–6.10 CNT/g Cu·h) at 850–900 °C. Additionally, hydrogen-assisted CVD can activate inert copper catalysts, e.g., Cu(NO 3 ) 2 /SiO 2 or Cu(CH 3 COO) 2/ SiO 2 , for the growth of CNTs.