Chapter 5 Pulsed Laser-Deposited TiO 2-based Films : Synthesis , Electronic Structure and Photocatalytic Activity

“ctive under visible light, photocatalysts based on doped titania were obtained via pulsed laser deposition PLD method. To find out the crystalline structure, optical properties, and electronic structure, the following techniques such as X-ray diffrac‐ tion, electronic spectroscopy, electrical conductivity measurements, and X-ray photoelectron spectroscopy XPS are used. Photocatalytic activity is monitored by applying the photoreduction of dichromate ions under UV and visible light. The influence of zirconium ions and its content and synthesis conditions on the efficiency of nitrogen incorporation into titania structure that, in turn, determines the electronic structure and photocatalytic ability of the semiconductive materials are discussed. “ substitutional nitrogen Ti N rather than an interstitial one Ti O N is mainly responsible for the observed photoactivity. It is pointed that substitutional nitrogen is responsible for bandgap narrowing or formation of intragap localized states within semiconductor bandgap. The bandgap energy values are sharply decreased, while the relative intensity of substitutional nitrogen XPS peaks is increased. Pulsed laser synthesis of TiO films in N /CH atmosphere not only leads to nitrogen incorporation but also to the formation of defects including oxygen vacancies and Ti + states which are all contributing to light absorption. “n appropriate ratio of gas mixture, optimum zirconia content, suitable pressure, and temperature during synthesis was found for the synthesis of highly active semiconductive films. The highest photocatalytic conver‐ sion yields are obtained for nitrogen-doped % ZrO /TiO synthesized in N CH = at Pa and at °C under both UV and visible light. © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.