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 has been one of the important contemporary worldwide issues. As a “green” technology, heterogeneous photocatalysis has attracted extensive attention for decomposition of hazardous pollutants [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 band gap (3.2eV), resulting in only UV light harvesting ability. One effective method to improve visible-light harvesting ability of TiO2 is combination of this semiconductor with narrow band gap semiconductors [2]. For this reason, we focused on integration of TiO2 with different narrow band gap semiconductors, which lead to high enhanced photocatalytic activity under visible light. Photocatalytic activity of the nanocomposites was examined by degradation of various pollutants under visible-light irradiation. It was observed that the nanocomposites showed substantially enhanced activity as compared with the pure TiO2. Effects of different parameters such as, preparation time and scavengers of reactive species on the kinetic of photodegradation reaction were investigated.