Band gap tuning of TiO2 NP–SWCNT nanocomposite materials using surfactant synthesis techniques

Abstract

Optimizing photocatalysts to function within the visible region offers enhanced economics considering that 40% of the sun’s energy is in the visible region, compared to just 4% in the UV region. To better utilize available solar flux, nanocomposite materials using TiO2 nanoparticles and single walled carbon nanotubes (SWCNTs) have been studied. Separating the SWCNT bundles using surfactants combined with a photo-assisted sol–gel preparation produced low band gap (<0.5 eV) materials. Infrared analysis showed the formation of Ti-O-C bonds that are attributed to photoactivity in the visible spectrum (i.e. red shift). The π–π stacking interactions between the benzene ring of the sodium dodecyl benzenesulfonate surfactant and the SWCNTs provided greater separation of the SWCNT fibers, increasing the coverage of TiO2 to SWCNT surfaces.