Integration of narrow band gap semiconductors with TiO2: Enhanced photocatalytic activity for removal of various pollutants under visible light

Nowadays, pollution of water owing to industrial development and population growth hasbeen one of the important contemporary worldwide issues. As a green technology,heterogeneous photocatalysis has attracted extensive attention for decomposition of hazardouspollutants [1]. TiO2 is a promising photocatalyst, because of its high stability, cost effectiveness,non-toxicity, and high oxidation ability. However, application of TiO2 is limited by its wide bandgap (3.2eV), resulting in only UV light harvesting ability. One effective method to improvevisible-light harvesting ability of TiO2 is combination of this semiconductor with narrow bandgap semiconductors [2]. For this reason, we focused on integration of TiO2 with different narrowband gap semiconductors, which lead to high enhanced photocatalytic activity under visiblelight. Photocatalytic activity of the nanocomposites was examined by degradation of variouspollutants under visible-light irradiation. It was observed that the nanocomposites showedsubstantially enhanced activity as compared with the pure TiO2. Effects of different parameterssuch as, preparation time and scavengers of reactive species on the kinetic of photodegradationreaction were investigated.