Characterization and relative photonic efficiencies of a new nanocarbon/TiO2 composite photocatalyst designed for organic dye decomposition and bactericidal activity

Two kinds of nanocarbon/TiO2 composite photocatalysts were synthesized using an MCPBA oxidation method, employing MWCNT (multi-wall carbon nanotubes) and C-60 as nanocarbon sources and TNB (titanium (IV) n-butoxide) as a titanium dioxide source. From the XRD patterns of the composites, structural variations revealed the C-60/TiO2 composite having a mixture of anatase and rutile forms, with the MWCNT/TiO2 composite presenting only the anatase phase. Elemental analysis indicated a predominance of carbon and Ti metal peaks over any other element. From the SEM results, the TiO2 particles were dispersed regularly on the fullerene surface with large clusters bearing irregular agglomerate dispersions. However, the MWCNT/TiO2 showed homogenous distributions with only individual MWCNT, covered with TiO2 and without any jam-like aggregates between the two. According to the photocatalytic results. the relationship of the -In (c/c(0)) of the solution products of the organic dye, methylene blue (MB), as a function of time under UV irradiation, showed linearity properties with first-order kinetics and an excellent photodegradation effect. From the measured bactericidal effects, the inhibition zone was defined by the halo method with the curves of E. coli inactivation denoting effectiveness of the nanocarbon/TiO2 composites in the sunlight. (C) 2008 Elsevier B.V. All rights reserved.