Chapter 23 - Investigation of the properties of oxide-based multilayer thin films and their use in the photocatalytic applications

Abstract

In recent times, as a fall out of rampant growth of mid-scale and heavy industries, environmental problems originating from the storing and discarding of highly toxic effluent pose critical concerns. Among several techniques proposed for the degradation and elimination of these chemical contaminants, photocatalytic process comes out as an effective, cheap, and green method. The use of oxide semiconductors to turn organic compounds into nontoxic compounds has been extensively studied in order to pave the way to reduce the damage to the environment due to pollution. Different approaches, including doping with metal and nonmetal, surface modification, nanocomposite, and multilayer fabrication, have been studied to enhance the photocatalytic activity of oxide semiconductors. Among these, multilayer thin films are attractive, owing to its superior optical, mechanical, and electrical properties, which are distinct from the monolayer thin films. The excellent properties of multilayer thin films can be optimized by careful control of growth conditions of the layers, the use of the appropriate number of layers, thickness, type of material applied as the layer, and chemical composition for each layer. This chapter provides an overview of research progresses in photocatalytic activity by multilayer thin films based on oxide semiconductors. Various preparation methods and their characteristics of oxide-based multilayer photocatalyst are studied. Deposition of suitable coatings and their combinations lead to considerable steps in the treatment of organic and inorganic pollutants.