TiO2 Nanostructures by Sol-Gel Processing

This book chapter discusses the versatile sol-gel processing technique that has been used to synthesize the nanostructures of titanium dioxide (TiO2) and their different morphologies. The sol-gel syntheses of different nanostructures of TiO2, namely TiO2 nanoparticles, nanocrystalline thin film, nanorods, nanofibers, nanowires, nanotubes, aerogels, and opals are described. These nanostructures have been characterized by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) whose images clearly depict the formation of the nanostructures. Some of the morphologies of nano-TiO2 such as nanorods, nanotubes, nanofibers, nanowires, have been synthesized by sol-gel process in combination with spin-coating, dip-coating, template, surfactant, diblock polymer, micelles, polystyrene. In comparison to the bulk TiO2, presence of porous and nanocrystalline morphologies has played a role in enhancing the performance in applications such as photovoltaics, photocatalysis, photocatalytic water-splitting, H2 storage, gas sensors, photochromic, opto-electronic, and electrochromic devices. The chapter concludes with challenges and practical concerns in using the sol-gel process to produce thin films of complex oxides, porous nanostructures, solid nanorods, nanotubes, which need to be addressed in future research efforts.