Preparation Of Doped Oxides Low Dimension Nanomaterial And Their Photocatalytic Activities Under Visible-light Irradiation

Semiconductor photocatalytic oxidation technique that is used for the removal of refactory organic pollutants becomes a focus of industrial waster water treatment, and the preparation of photocatalysts with high photoactivity is the key for its industrialization. Aiming at the disadvantages of recombination between the photogenerated electrons-holes and the low efficiency for the utilization of visible light in the typical photocatalysts, several low dimension oxides nanomaterials with high photocatalytic activity were prepared by doping ion, which promoted the separation of the photogenerated electrons-holes and broaden the light adsorption spectrum into the visible region. The main contents of the thesis were discussed as follows:(1) The Zn1-xMnxO and Zn1-xCoxO photocatalysts were prepared separately by precipitation method. The light absorption edges of Mn2+,Co2+-doped zinc oxide shifted to the long wave direction with an increase of Mn2+,Co2+ doping amounts. It should be pointed that the order of photocatalytic activity was the same as that of PL intensity, namely, the stronger the PL intensity, the higher the photocatalytic activity; The Zn0.95Mn0.05O and Zn0.95Co0.05O photocatalysts with the highest fluorescence intensity exhibited the highest photocatalytic photodegradation efficiency of xanthate under visible-light irradiation.(2) Sm, C, S-tridoped porous TiO2 nanoparticles were prepared by one-step hydrothermal method. The porous structure made the BET specific surface area up to 170m2·g-1. Doping porous TiO2 nanoparticles with C and S could not only broaden the light adsorption spectrum into the visible region (400～600 nm), but also enhance their visible light absorption ability. Sm3+ played the role of the electron capture agent and transferring electron, which further improved photocatalytic activity. The photocatalyst doped with C, S, and 1.0% Sm3+ showed the highest photocatalytic activity under visible light irradiation. (3) C, N, S co-doped TiO2 nanotubes were prepared by thermal treatment of the complex of H-titanate nanotubes and thiourea. The BET specific surface area was up to 193m2·g-1.The nano-confinement of thiourea in the inner space of H-titanate nanotubes was the key factor for multinonmetal co-doping. Doping TiO2 nanotubes with C, N and S could not only broaden the light adsorption spectrum into the visible region (400～600 nm), but also enhance their visible light absorption ability. At thiourea/Ti=6, C, N, S co-doped TiO2 nanotubes exhibited the highest photocatalytic activity under visible light irradiation.(4) C, N, S co-doped mesoporous TiO2(B) nanobelts were prepared by thermal treatment of the complex of H-titanate nanobelts and thiourea. The appropriate porous structure was conductive to increase the BET specific surface area, meanwhile facilitating the diffusive migration of the xanthate. Doping porous TiO2 nanobelts with C, N and S could not only broaden the light adsorption spectrum into the visible region (400～600 nm), but also enhance their visible light absorption ability; At thiourea/Ti=3, C, N, S co-doped TiO2 nanobelts exhibited the highest photocatalytic activity under visible light irradiation..