Synthesis of carbon nanotube/ZnO nanocomposites using absorbent cotton and their photocatalytic activity

Abstract

Carbon nanotubes (CNTs) and ZnO-coated carbon nanotubes (CNT/ZnO) nanocomposites were synthesised by a rapid heating of absorbent cotton and mixtures of suspension of Zn(OH)2/absorbent cotton at about 600°C, respectively. The products were characterised by X-ray diffraction, scanning electron microscopy, selected area diffraction, Raman spectrum, energy dispersive spectrum and infrared absorption spectroscopy. The photocatalytic activity of the CNT/ZnO nanocomposites for the degradation of rhodamine B (RhB) was investigated under ultraviolet (UV) light irradiation. The results show that the structure of the synthesised CNTs is middle-hollow, with inner and outer diameter of about 10 and 80 nm, and their average length is more than 1 µm. ZnO nanoparticles on the surface of CNTs are nonuniform with a sheet shape, and the outer diameter of the CNT/ZnO nanocomposites is about 110 nm. The degradation efficiency of RhB by the CNT/ZnO nanocomposites was higher than that by other catalysts such as CNTs, pure ZnO and the simple mechanical mixtures of CNTs and ZnO, which came up to 98% after 2 h UV light irradiation.