Fabrication, Characterization and Photocatalytic application of sol-gel derived MWCNT-ZnO hybrid nanomaterial

In the present study, multiwall carbon nanotubes-ZnO nanoparticles (MWCNT-ZnO) hybrid nanomaterials were prepared by a simple and efficient in-situ sol-gel process. Zinc acetate (Zn(CH3COO)2 .2H2O), diethylene glycol (DEG, C4H10O3), and functionalized MWCNTs with carboxyl(COOH) and hydroxyl(OH) functional groups were used as the main Precursors. Three different mass ratio of MWCNT: ZnO =3:1, 1:1 and 1:3 were examined. The synthesized nanomaterials were characterized by Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Energy Dispersive X-ray spectroscopy (EDX), X-ray map of elemental distribution (Xmap) and Fourier Transform InfraRed spectroscopy (FTIR). Successful growth of MWCNT-ZnO hybrid for both COOH and OH functional groups and all three mass ratios were obtained. SEM and TEM observations revealed that the ZnO nanoparticles were attached on the surface of MWCNTs and had rather spherical shapes. By increasing the concentration of ZnO, the sizes of ZnO nanoparticles in hybrid material were increased. The most uniform distribution of ZnO nanoparticles was obtained for 1:1 MWCNT-ZnO mass ratio. It was also observed that the hybrids which were made by carbon nanotubes with carboxyl functional groups had nearly smaller sizes and more uniform distribution of ZnO nanoparticles decorated MWCNTs’ surface compared to hydroxyl one. To investigate the photocatalytic activity of the synthesized hybrid nanostructures, degradation of methylene blue(MB) under UV irradiation was performed. Compared with pure ZnO and MWCNTs, the decomposition efficiency of MWCNT-ZnO hybrids is higher in the MB degradation processes. MWCNT-COOH-ZnO with concentration ratio of 1:3 showed the best photodegradation efficiency.