Multi-walled carbon nanotubes(MWCNTs)/TiO_(2)composite photocatalysts with high photoactivity were prepared by sol-gel process and further characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),Fourier transform infrared(FT-IR),and UV-vis absorption spectra.Compared to pure TiO_(2),the combination of MWCNTs with titania could cause a significant absorption shift toward the visible region.The photocatalytic performances of the MWCNTs/TiO_(2)composite catalysts were evaluated for the decomposition of Reactive light yellow K-6G(K-6G)and Mordant black 7(MB 7)azo dyes solution under solar light irradiation.The results showed that the addition of MWCNTs enhanced the adsorption and photocatalytic activity of TiO_(2)for the degradation of azo dyes K-6G and MB 7.The effect of MWCNTs content,catalyst dosage,pH,and initial dye concentration were examined as operational parameters.The kinetics of photocatalytic degradation of two dyes was found to follow a pseudo-first-order rate law.The photocatalyst was used for seven cycles with photocatalytic degradation efficiency still higher than 98%.A plausible mechanism is also proposed and discussed on the basis of experimental results.
In this report, a novel thermosensitive poly（N-isopropylacrylamide-co-maleic anhydride-β-cyclodextrin）/（TiO2-multi-wal,led carbon nanotubes） （poly（NIPAM-co-MAH-β-CD）/（TiO2-MWCNTs）） composite was synthesized by UV light photoinitiating method. The results indicated that MAH modifiedβ-CD （MAH-β-CD） could polymerize to NIPAM by UV light irradiation in the presence of TiO2-MWCNTs composite nanoparticles. The characteristic results confirmed that the TiO2-MWCNTs composite nanoparticles were embedded evenly within the thermally responsive copolymer of NIPAM and MAH-β-CD. The effects of irradiation time and TiO2-MWCNTs concentration on the yield of the composites were investigated by keeping NIPAM to MAH-β- CD mass ratio constant. The optimal polymerization reaction conditions were a TiO2-MWCNTs concentration of 10 wt.% under UV light for the illumination of 3 h.
