Effects of the acid pretreated multi-walled carbon nanotubes on the photocatalytic capacity of TiO ₂ /multi-walled carbon nanotubes nanocomposites

Abstract

This Letter investigates the effect of the acid pretreated multi-walled carbon nanotubes (MWNTs) on the photocatalytc activity of TiO2/MWNTs nanocomposites prepared by sol–gel process. Synthesised nanocomposite materials were characterised by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) adsorption analysis, photoluminescence (PL) spectroscopy and transmittance electron microscopy (TEM). The photocatalytic capacities of the nanocomposites were determined by the oxidation of NO over the photocatalyst under UV light. Results indicate that the nanocomposite's efficiency of NOx photodegradation increases (from 20.5 to 34.3%), as the acid pretreatment time increases from 0 to 4 h. The optimal acid pretreatment time for the photoactivity of nanocomposite was 4 h. This Letter shows the acid pretreatment time plays an important role in determining the physicochemical properties of materials, as it consequently influences the photocatalytic capacity of TiO2/MWNTs nanocomposites.