Preparation Of TiO₂ Nanomaterial And Its Photocatalytic Properties

Ti O2, Zn O, Sn O, Zr O2 and Cd S are very excellent photocatalysts. However, among these semiconductors, Ti O2 has attracted much more attentions owing to its super-hydrophilicity, high chemical stability, non-toxic, cheaper and high photocatalytic activity. In this article, the N-doped rutile, multilayered nanospheres anatase and N/F co-doped Ti O2 were synthesized by one-step hydrothermal method. Ti-Cu amorphous alloy was used as Titanium source, Na2SO4 and Na F were used as surfactant. In addition, the photocatalytic selectivity and degradation activity of Ti O2 nanomaterials were determined by testing the photodegradation of organic dyes. Their photocatalytic performance have been improved by the way of heat treatment.The N-doped rutile nanoflowers were synthesized by one-step hydrothermal method without any surfactant. Its absorption edge has shifted to the visible region. Among the rhodamine B, methyl orange and methylene blue, N-doped rutile prefer to photodegrade rhodamine B under identical condition. The photocatalytic degradation efficiency of Rh B was 92%. After heat treatment, its photocatalytic activity has been enhanced. The photocatalytic activity was the best when the calcination temperature was 550 0C.When Na2SO4 was used as surfactant, multilayered nanospheres anatase was fabricated. The adsorption of SO42- ions on the surface of multilayered nanospheres anatase could enhance its surface acidity. The adsorbed SO42- ions not only increase the number of strong Lewis acidic sites, but also induce a large amount of strong Br?nsted acidic sites on the surface of anatase. These strong Lewis and Br?nsted acidic sites could provide more surface chemisorption centers for reactants as well as oxygen molecules, and also efficiently captured the photo induced electron, which would greatly prohibit the undesirable electron–hole pair recombination, furthermore, increase the lifetime of photon-generated carrier and improve the photocatalytic efficiency. It is evident that the multilayered nanospheres anatase would exhibit much higher photocatalytic degradation activity for methyl orange compared with the P25. Their photocatalytic performance had been improved by the way of heat treatment. The photocatalytic activity was the best when the calcination temperature was 700 0C.The microstructure and composition of samples were various with the increase of Na F concentration from 1.6 to 80 m M. When the concentration of Na F was less than 16 m M, the N/F co-doped Ti O2 with mixed rutile and anatase was synthesized, and the amount of the anatase phase increased with the increase of the Na F concentration. When the concentration of Na F was more than 48 m M, the mixed anatase and(NH4)0.3Ti O1.1F2.1 precursor with hexagonal prism structure were formed. The N/F co-doped Ti O2 was got by a thermal treatment at 550 0C for 1 h. The photocatalytic activity of as-prepared Ti O2 was evaluated through the decomposition of rhodamine B under the visible light irradiated. After heat treatment, its photocatalytic stability is improved.