Photoelectrochemical and Electrocatalytic Behaviors of TiO 2 Nanostructures and TiO 2 −Au Nanocomposites: Effect of Synthesis Conditions

Mesoporous TiO 2 nanostructures and TiO 2 −Au nanocomposites with stabilized Au nanoparticles are synthesized by the template sol-gel process. The effects of synthesis conditions on the particle size, electronic structure, morphology, composition, and texture of prepared materials are determined. TiO 2 - and TiO 2 −Au-based electrodes are shown to be photoactive in the wavelength range of 250–412 nm and in the methylene blue (MB) photodecomposition and feature high catalytic activity in an oxygen electroreduction reaction. The presence of hydroxyl and carboxylate groups in the amorphous phase is the key factor affecting the photosensitivity of our TiO 2 nanostructures and contributing to enhancement of their photoactivity in the MB photodecomposition reaction. Due to their catalytic activity and consistent performance in the oxygen electroreduction reaction, the TiO 2 nanostructures and TiO 2 −Au nanocomposites can be considered as promising materials for use in electrochemical oxygen sensors with application to aqueous solutions.