OICC Press International Nano Letters 2228-5326 7 1 (March 2017) 2016 12 23 The effect of concentration ratio and type of functional group on synthesis of CNT–ZnO hybrid nanomaterial by an in situ sol–gel process 10.1007/s40089-016-0197-4 EN Sekineh Hosseini Largani Department of Solid State Physics, Faculty of Basic Science, University of Mazandaran, Babolsar, 47416-95447, IR Mohammad Akbarzadeh Pasha Department of Solid State Physics, Faculty of Basic Science, University of Mazandaran, Babolsar, 47416-95447, IR Research Laboratory of Carbon-based Nanostructures, Faculty of Basic Science, University of Mazandaran, Babolsar, IR Journal Article 2016 12 23 Abstract In this research, MWCNT–ZnO hybrid nanomaterials were synthesized by a simple sol–gel process using Zn(CH 3 COO) 2 ·2H 2 O and functionalized MWCNT with carboxyl(COOH) and hydroxyl(OH) groups. Three different mass ratios of MWCNT:ZnO = 3:1, 1:1 and 1:3 were examined. The prepared nanomaterials were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR). Successful growth of MWCNT–ZnO hybrids for both COOH and OH functional groups and all the three mass ratios were obtained. The ZnO nanoparticles attached on the surfaces of CNTs have rather spherical shapes and hexagonal crystal structure. By increasing the concentration of ZnO, the number and average size of ZnO nanoparticles decorated the body of CNTs in hybrid structures increase. By increasing the ZnO precursor, the distribution of ZnO nanoparticles that appeared on the surface of CNTs becomes more uniform. The SEM observation beside EDX analysis revealed that at the same concentration ratio the amount of ZnO loading on the surface of MWCNT-COOH is more than MWCNT-OH. Moreover, the average size of ZnO nanoparticles attached on the surface of COOH functionalized CNTs is relatively smaller than that of OH functionalized ones.