Papers by Author: Hong Ying Dong

Abstract: Ti/Si/C element powders were used to synthesize Ti₃SiC₂ by spark plasma sintering. The synthesized products consisted of Ti₃SiC₂, together with TiC and Ti₅Si₃ as impurities. The addition of Al, excess Si, and appropriate sintering temperature increased the purity of Ti₃SiC₂ in the products. From the 3Ti/1.2Si/2C/0.2Al mixture, Ti₃SiC₂ with the purity 99 mass % was synthesized at 1300 °C for 5 min at 30 MPa.

Abstract: The PVP+Ti (OC₄H₉)₄+SnCl₄·5H₂O/sesame oil composite fibers were successfully prepared by a sol-gel method combined with a coaxial electrospinning technique. The Sn⁴⁺/TiO₂ nanotubes were obtained by calcining the above-mentioned composite fibers and characterized by XRD and TEM. XRD results show that increasing reaction temperature facilitates to form a stable phase. TEM results show that the Sn⁴⁺/TiO₂ nanotubes have smooth surface with wall thickness of ~120 nm and are composed of small particles of ~5 nm. The photocatalytic activity of Sn⁴⁺/TiO₂ nanotubes was investigated. The photodegradation efficiency of Sn⁴⁺/TiO₂ nanotubes decreases in UV region but increases in visible light region. The photocatalytic properties of three 0.52at% Sn⁴⁺/TiO₂ nanomaterials with different morphologies were also evaluated. The photodegradation efficiencies of Sn⁴⁺/TiO₂ nanopowers, Sn⁴⁺/TiO₂ nanofibers and Sn⁴⁺/TiO₂ nanotubes increase in visible light region in sequence. In summary, chemical modification by doping Sn⁴⁺ and morphology changing for TiO₂ can improve its photocatalytic activity in visible light region significantly.

Abstract: TiO₂ nano powder doping with Sn⁴⁺ was directly synthesized by a low temperature hydrothermal method using tetrabutyl titanate (TBOT) as a Ti resource and NH₄Cl as a dispersant. The synthesized nano powder was characterized by XRD, BET, TEM and EDS analyses. XRD results show that increasing reaction temperature facilitates to form a stable phase, and the synthesized nano power size is uniform with particle size of 10-20 nm. Doping Sn⁴⁺ ion does not result in an obvious lattice distortion. The effect of doping Sn⁴⁺ ion on photocatalytic activity in visible light region for modified TiO₂ was investigated by degrading methylene blue solution.