Synthesis, Characterization of Doped Zinc Oxide Nanostructure and its Photocatalytic Application

Recently titanium dioxide photocatalyst have been used successfully in different fields, for example, airpurification, self cleaning, deodorizing and sterilization. However, the major issue is that with TiO₂ photocatalyst we can utilize only the UV light which exhibit only 2-3% of solar light. For the improvement of photocatalytic degradation of pollutants at λ > 400 nm, few types of photocatalysts have been tried such as transition metal ion implanted TiO₂, reduced TiO₂, dye-sensitized TiO₂. Other semiconductors as photocatalysts have been examined by few research groups. In the recent years, ZnO semiconductors, has gotten much attention because of his wide and direct band gap of 3.37 eV at room temperature, minimum cost and environmentally friendly quality. However, the reactivity of ZnO with nanometer dimensions depends essentially on the optical and electronic properties; it is transparent invisible region. Therefore, ZnO semiconductor is broadly used in photocatalytic degradation of organic and inorganic pollutants. Some issues still remain to be solved in its application, such us the quick recombination of photogenerated electron-hole pairs. In this manner enhancing photocatalytic activity by modification has become a interesting topic among researches in recent years. Transition metal doping and coupling semiconductors are the most way. In like manner, several techniques have been used for the synthesis of undoped and doped ZnO. This survey focused on the different synthesis methods of ZnO and its application in dye degradation.