Papers by Author: Hong Tao Gao

Abstract: Sm, Zr doped nanocrystalline TiO2 powers were prepared successfully by a facile ultrasonic assisted sol-gel method. The products were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. X-ray diffraction peaks could be assigned to anatase TiO2, which confirms the crystallinity of the as-prepared samples. The SEM images demonstrated that the crystalinity is formed with spherical aggregates with average diameters ranging from 10 to 20 nm. The photocatalytic activity was studied on the photocatalytic degradation of methyl orange (MO) aqueous solution irradiated with UV-visible light. Under UV-visible light irradiation, the photocatalytic performances of the doped samples were much better than that of pure TiO2, and the co-dopant showed highest. It demonstrated that a strong Sm-Zr synergistic interaction might play a decisive role in driving the excellent photocatalytic performance of TiO2.

Abstract: Sm doped nanocrystalline TiO2 powers were prepared by ultrasonic assisted sol-gel synthesis. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and UV-visible diffuse reflectance spectra (DRS), respectively. Both of undoped TiO2 and Sm-TiO2 samples exclusively consist of primary anatase crystallites, which further form spherical aggregates with average diameters ranging from 11 to 19 nm. The photocatalytic activity of Sm-TiO2 was investigated on the photocatalytic degradation of methyl orange (MO) aqueous solution under UV visible light irradiation. Sm doping improves effectively the photocatalytic activity under UV light irradiation with an optimal doping concentration of 0.5%. The photocatalytic mechanisms of Sm-TiO2 catalysts were tentatively discussed

Abstract: Reactions of (R₃Sn)₂O (R=Ph, 2-ClC₆H₄CH₂, 2-FC₆H₄CH₂, 4-CNC₆H₄CH₂) with 5-chloro-6-hydroxynicotinic acid in 1/2 stoichiometry yielded eight triorganotin compounds. These compounds have been characterized by elemental analysis, IR and NMR spectroscopy. The crystal structures of triphenyltin esters of 5-chloro-6-hydroxynicotinic acid were determined by single crystal X-ray diffraction. In the compound, the tin atoms are rendered five-coordinated in a trigonal bipyramidal structure by coordinating though the three phenyl carbon atoms and two oxygen atoms one from carboxylate and other from the phenolic hydroxide. The resulting structure is one-dimensional linear polymers through an interaction between the O atoms of phenolic hydroxide and tin atoms of an adjacent molecule.

Abstract: Nanocrystalline samples of titanium dioxide (TiO₂) monodoped or co-doped with La and Y were prepared by a facile method, using Ti(OC₄H₉)₄ as the precursor. All products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and UV-visible diffuse reflectance spectra (DRS), respectively. Photocatalytic activities of the products were assessed by the photocatalytic decomposition of methyl orange (MO). Both of undoped TiO₂ and doped-TiO2 samples exclusively consist of primary anatase crystallites, which further form spherical aggregates with diameters ranging from 14 to 21 nm. The photocatalytic performances of rare earth (RE) element co-doped samples were much higher than that of single doped and pure TiO2 under UV-visible-light irradiation. It indicated that a strong La-Y synergistic interaction appeared to play a decisive role in driving the excellent photocatalytic performance of LYT.

Abstract: N, Cd-codoped TiO2 has been synthesized by sol-gel method coupling with thermolysis. The products were characterized by XRD, SEM, UV-visible DRS, XPS and BET analysis, respectively. The photocatalytic activities of samples were evaluated on the degradation of methyl orange (MO). It was showed that particle sizes of anatase photacatalysts were about 10-15 nm. The maximum specific surface area of the products was 102.7 m2⋅g-1. N atoms were incorporated into the TiO2 crystal lattice, while Cd atoms existed on the crystal surface. The optical absorption edge of N, Cd-codoped TiO2 was 435 nm, which illustrated that the product represented photoactivity in the visible region. It indicated a strong N-Cd synergistic interaction appeared to play a decisive role in driving the excellent photoactivity performance of N,Cd-codoped TiO2.