Visible-Light Photocatalytic Property of Titanate Nanotubes Sensitized by Several Porphyrins

Abstract

The visible-light photocatalytic activity of titanate nanotubes (TiNTs) sensitized by 5,10,15,20-tetraphenylporphyrin (TPP), 5,10,15,20-tetraphenylporphyrin manganese (MnTPP), 5,10,15,20-tetraphenylporphyrin nickel (NiTPP) and 5,10,15,20-tetraphenylporphyrin zinc (ZnTPP), respectively, was investigated by the photocatalytic degradation of methyl orange (MO) as a probe reaction. The results showed that the central ions of porphyrins had an important influence on the photocatalytic activity of the samples. The activity was in the order of TiNTs-ZnTPP > TiNTs-TPP > TiNTs-NiTPP > TiNTs-MnTPP. Combined the result of absorption spectra with that of fluorescence spectra, it was demonstrated that various visible-light absorption and photoelectron transfer caused by the central ions of porphyrins were the decisive factor for the visible-light photocatalytic activity of the sensitized TiNTs.

Heterogenization of water-soluble porphyrins in Ti/TiO2 nanotubes electrodes: experimental and theoretical insights for atrazine degradation

“…In the photo(electro)catalysis systems, despite the different reaction orders, the manganese porphyrins had no positive contribution in the degradation of the substrate. As already proposed by Li and coworkers (Li et al 2011), the manganese porphyrin (a similar one; their manganese porphyrin macrocycle has no -COOH groups) could not be able to transfer its photo-induced electrons to the conduction band of the titanium nanotubes. The ATZ degradation observed in the PC had an exclusive contribution to the light since the presence of the TiO 2 did not provide any change concerning the photolysis system.…”