A simple strategy for the anchoring of anatase titania on multi-walled carbon nanotubes for solar energy harvesting

•TiO2 nanoparticles anchored on MWCNTs surface by using simple sol-gel method at room temperature.•TiO2-MWCNTs nanocomposite shows red shift.•Nanocomposites generated OH species in the presence of visible light.•Solar cell efficiency increase (0.090–3.46%) with increase in concentration of MWCNTs nanocomposite. Pure anatase titania (TiO2) nanoparticles were anchored on the surface of functionalized multi-walled carbon nanotubes (MWCNTs) using a solution-based synthetic method at room temperature. X-ray diffraction and Raman patterns were used to analyze the structural and phase composition of these nanocomposites, highlighting the formation of anatase TiO2 nanoparticles with MWCNTs up to 0.5wt.%. The non-spherical particles of TiO2 in the order of 7–12nm, were confirmed through transmission electron microscopy analysis and these particles were well dispersed on the MWCNTs. The optical absorption spectra of these structures were studied by diffuse reflectance UV–visible spectroscopy. The optical energy band gap of the various nanocomposites was observed from 3.2 to 2.6eV with an increasing amount of MWCNTs, up to 0.5wt.%. The generation of OH species in nanocomposites in the presence of visible light irradiation was investigated by photoluminescence spectroscopy. Photoelectrochemical cell performance of TiO2-MWCNTs for 0.5wt.% content of MWCNTs under light intensity 100mW/cm2 showed a significant improvement of short-circuit current density from 1.23 to 12.1mA/cm2 and a cell efficiency (0.090–3.46%) that is better than many reported anatase-based compositions without sensitizer.