Titanate Nanorods Modified with Nanocrystalline ZnS Particles and Their Photocatalytic Activity on Pollutant Removal

Aiming to produce materials with enhanced photocatalytic properties, the synthesis of new crystalline nanocomposites by combining titanate nanorods (TNR) with ZnS nanocrystallites is described in this work. The TNR modification was accomplished by an in situ nucleation and growth process of ZnS nanoparticles. Zinc diethyldithiocarbamate was used as the metal chalcogenide precursor. The prepared materials were structural, morphological and optical characterized by X-ray diffraction, transmission electron microscopy and high resolution transmission electron microscopy, energy dispersive spectroscopy and powder diffuse reflectance spectra. Crystalline ZnS nanoparticles were obtained as a homogeneous and continuous layer, covering completely the TNR surface. The application of these new nanocomposite materials on photocatalytic degradation of pollutants was investigated. First, the evaluation of hydroxyl radical formation, using the terephthalic acid as probe, was studied. Afterwards, the adsorption and photodegradation of safranine-T, used here as a model pollutant molecule, was investigated. The obtained data indicate that the prepared nanocomposites have potential to be used as photocatalysts for organic pollutant removal. The best removal results (97% removal) were obtained using the 0.01ZnS/HTNR sample as catalyst (0.2 g/L; 10 ppm safranin-T solution) with a combination of a low dye adsorption (20%) and a high dye photocatalytic degradation (77%).