Synthesis and sensoric response of ZnO decorated carbon nanotubes

ZnO nanoparticles of size 2-10 nm were generated in situ from the single source precursor [2-(methoxyimino)propanoato]zinc(ii), ([CH ₃ONCCH₃COO]₂Zn·2H₂O) onto multiwalled carbon nanotubes (MWCNTs) at low temperature (150 °C). The degree of ZnO coverage on the MWCNTs can be tuned and is dependent upon the ZnO precursor concentration. A plausible growth mechanism based on surface saturation of as-deposited precursor on the MWCNTs has been proposed. The X-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) indicate the nano-crystalline nature of the ZnO particles. Scanning electron microscopy (SEM) and TEM investigations of the ZnO deposition revealed a dense and homogeneous deposition along the complete periphery of the MWCNT. The ZnO/MWCNT nanocomposite hybrid materials were further electronically characterized by micro-Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectroscopy (UV-Vis) as well as room temperature photoluminescence (PL). The nanostructured ZnO/MWCNT composite shows a better sensing performance when compared to bare MWCNTs in the detection of low CO levels (20-200 ppm).