The photocatalytic properties of anatase TiO(2) nanorods (NRs) and noble metal-semiconductor nanocomposites (TiO(2) NRs/Ag) prepared by colloidal chemistry routes and immobilized onto suitable substrates were investigated. Photocatalytic experiments were performed under UV irradiation in order to test the degradation of a target compound (the azo dye, methyl red) in aqueous solution using TiO(2) P25 Degussa as a reference material. Absorbance spectroscopy and liquid chromatography/mass spectrometry (LC/MS) measurements pointed out that, according to pH conditions, TiO(2) NRs and TiO(2) NRs/Ag presented a photoactivity up to 1.3 and 2 times higher than TiO(2) P25 Degussa, respectively. Notably, the TiO(2) NRs/Ag-based catalysts demonstrated a photocatalytic activity 2-fold higher than bare TiO(2) NRs. Remarkably, only a negligible dependence on pH conditions was detected for the nanocomposite catalyst, whereas both TiO(2) NRs and TiO(2) P25 Degussa showed much higher photoactivity at acidic pH. In all the investigated cases, the identified byproducts pointed out the occurrence of the same reaction mechanism, basically relying on the hydroxyl radical attaching on the benzene ring and on the homolytic rupture of the nitrogen-carbon bond of the dimethyl-amino moiety.
Photocatalytic Activity of Nanocomposite Catalyst Films Based on Nanocrystalline Metal/Semiconductors
FANIZZA, ELISABETTA;AGOSTIANO, Angela;Curri M. Lucia;
2011-01-01
Abstract
The photocatalytic properties of anatase TiO(2) nanorods (NRs) and noble metal-semiconductor nanocomposites (TiO(2) NRs/Ag) prepared by colloidal chemistry routes and immobilized onto suitable substrates were investigated. Photocatalytic experiments were performed under UV irradiation in order to test the degradation of a target compound (the azo dye, methyl red) in aqueous solution using TiO(2) P25 Degussa as a reference material. Absorbance spectroscopy and liquid chromatography/mass spectrometry (LC/MS) measurements pointed out that, according to pH conditions, TiO(2) NRs and TiO(2) NRs/Ag presented a photoactivity up to 1.3 and 2 times higher than TiO(2) P25 Degussa, respectively. Notably, the TiO(2) NRs/Ag-based catalysts demonstrated a photocatalytic activity 2-fold higher than bare TiO(2) NRs. Remarkably, only a negligible dependence on pH conditions was detected for the nanocomposite catalyst, whereas both TiO(2) NRs and TiO(2) P25 Degussa showed much higher photoactivity at acidic pH. In all the investigated cases, the identified byproducts pointed out the occurrence of the same reaction mechanism, basically relying on the hydroxyl radical attaching on the benzene ring and on the homolytic rupture of the nitrogen-carbon bond of the dimethyl-amino moiety.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
