Increase of the photocatalytic activity of TiO2 by carbon and iron modifications

Abstract

Modification of TiO 2 by doping of a residue carbon and iron can give enhanced photoactivity of TiO 2. Iron adsorbed on the surface of TiO 2 can be an electron or hole scavenger and results in the improvement of the separation of free carriers. The presence of carbon can increase the concentration of organic pollutants on the surface of TiO 2 facilitating the contact of the reactive species with the organic molecules. Carbon-doped TiO 2 can extend the absorption of the light to the visible region and makes the photocatalysts active under visible-light irradiation. It was proved that TiO 2 modified by carbon and iron can work in both photocatalysis and photo-Fenton processes, when H 2 O 2 is used, enhancing markedly the rate of the organic compounds decomposition such as phenol, humic acids and dyes. The photocatalytic decomposition of organic compounds on TiO 2 modified by iron and carbon is going by the complex reactions of iron with the intermediates, what significantly accelerate the process of their decomposition. The presence of carbon in such photocatalyst retards the inconvenient reaction of OH radicals scavenging by H 2 O 2, which occurs when Fe- TiO 2 photocatalyst is used.