Effect of Temperature in Hydrothermally Rutile TiO2 Nanorod Synthesis for Photocatalytic applications

In this article, role of temperature in rutile TiO2 nanorod synthesis by hydrothermal method was investigated due to one-dimensional oriented nanostructures application importance. Synthesis was studied at three level of temperatures such as 125, 150 and 175 ºC. The result of XRD, SEM and UV-Visible tests showed that crystallinity and crystallite size would increase in order to increment temperature, furthermore, the length and partly diameter of nanorods would enhance when temperature increased. Indeed, the length of nanorod at 125 ºC was about 0.5 microns, however, at 175 ºC was 1.7 microns. Moreover, photocatalytic activity of nanorods by measurement the degradation of methylene blue would increase but the efficiency would decrease when the temperature enhanced. Absorption diagram at different wavelengths demonstrated that the synthesized TiO2 nonarods had no absorption in UV region and also absorption decreased at higher wavelengths. The band gap for all samples were near 3 ev. The optimum temperature for reaching to best efficiency was 150 ºC.