1D Titanium Dioxide: Achievements in Chemical Sensing.

For the last two decades, titanium dioxide (TiO2) has received wide attention in several areas such as in medicine, sensor technology and solar cell industries. TiO2‑based gas sensors have attracted significant attention in past decades due to their excellent physical/chemical properties, low cost and high abundance on Earth. In recent years, more and more efforts have been invested for the further improvement in sensing properties of TiO2 by implementing new strategies such as growth of TiO2 in different morphologies. Indeed, in the last five to seven years, 1D nanostructures and heterostructures of TiO2 have been synthesized using different growth techniques and integrated in chemical/gas sensing. Thus, in this review article, we briefly summarize the most important contributions by different researchers within the last five to seven years in fabrication of 1D nanostructures of TiO2‑based chemical/gas sensors and the different strategies applied for the improvements of their performances. Moreover, the crystal structure of TiO2, different fabrication techniques used for the growth of TiO2‑based 1D nanostructures, their chemical sensing mechanism and sensing performances towards reducing and oxidizing gases have been discussed in detail.