Enhanced NO2 response of hydrothermally grown Ti doped WO3 nanostructures

Titanium doped WO3 (Ti doped WO3) nanostructures were synthesized by hydrothermal synthesis by the controlled hydrolysis of Na2WO4 using oxalic acid and Titanium tetrachloride. Prepared samples were characterized by X-ray powder diffraction (XRD), scanning electronic microscopy (SEM), and transmission electron microscopy (TEM). As-synthesized pristine WO3 showed nanorods with diameters of about 10–15 nm and length about 1.2 µm and Ti doped WO3 composed of numerous small nanocrystals. Introduction of Ti doping by chemical synthesis process suppressed the growth of one-dimensional nanorods along their axis direction and shows agglomeration of particulate like morphology and no elongated structures. Ti doping not only lowered the optimal operating temperature of WO3 nanostructures sensors from 250 to 200 °C but also increased the maximum value of sensor response. Also the Ti-doped WO3 nanostructures exhibited rapid response characteristic to NO2 gas compared to pristine WO3.