Photocatalytic Properties of Semiconductive Oxide Nanoparticles. From Fundamentals to Applications

Abstract

Photocatalysis is a promising technology that demonstrated important applications in environmental systems such as air purification, pollution removal, self-cleaning and antimicrobial. Semiconductive oxides (e.g., ZnO, TiO₂, CuO) are important photocatalytic materials that can act as sensitizes for light based redox processes due to their electronic structure, which is characterized by the conduction-band with electrons (good reductants) and the valence band with holes (powerful oxidants). Excitation of electrons from the conduction-band and valenceband holes can react with electron donors and electron acceptors adsorbed on the semiconductor surface and electric double layer around the particles. The band gap value determines the semiconductive behavior of oxide nanoparticles. The absorption of UV-Vis radiation is an important tool for evaluating photocatalytic behavior of the obtained semiconductive nanoparticles. In this paper we present the correlation between the band gap value, particle size and the photocatalytic activity of ZnO nanoparticles prepared via an aqueous solution chemical method.