<p>Nanocomposites of multi-wall carbon nanotubes (MWCNTs)/zinc oxide (ZnO) were produced successfully using the sol-gel method. The structural, morphological and chemical properties of the nanostructured ZnO is studied after composited with three different amounts of MWCNTs (1, 2, 5 wt%). X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray analysis (EDS), Brunauer Emmett Teller (BET) surface area analyzer and Raman scattering spectroscopy were employed for the characterization of the samples. The XRD analysis of all samples indicate the presence of a wurtzite hexagonal nanocrystalline structure of the ZnO compound, with no detection of any other phases. The FE-SEM images of nanocomposite samples show a porous structure with elongated MWCNTs. The size of ZnO nanoparticles, as measured from the FE-SEM images, shows a progressive reduction, 29.75, 28.60, 24.74, and 22.59&#xa0;nm for pure ZnO, 1, 2, and 5 wt% MWCNT, respectively. The EDS analysis confirm the presence of Zn, O, and C, consistent with the XRD results indicating the formation of ZnO nanoparticles. The presence of MWCNTs in the ZnO/MWCNT nanocomposite was confirmed by Raman spectroscopy, which showed characteristic D and G bands at 1357 and 1588&#xa0;cm⁻¹, respectively. Based on the BET analysis, the specific surface areas increase due to presence of MWCNTs in the structure. The specific surface areas of the samples are 15, 19, 17, and 29 m²/g for pure ZnO, 1, 2, and 5 wt% MWCNT, respectively. The ZnO/5%MWCNT nanocomposite demonstrate a twofold increase in photocurrent density (3.75 µA.cm^− 2) compared to the bare ZnO photoelectrode, along with enhanced optical and electrochemical properties. These results suggest the great potential of ZnO/MWCNT nanocomposites for photocatalytic applications and energy conversion.</p> Graphical abstract <p></p>