Papers by Keyword: Copper Doping

Abstract: In this work, vertically aligned titania nanotube arrays (TNTs) were fabricated on Ti surface in fluoride-containing electrolytes by anodization. TNTs were treated by hydrothermal treatment in the saturated solution of [Cu(NH₃)₄ (H₂O)₂]²⁺. Different hydrothermal treatment conditions were studied to obtain the best modification effect in the experiment. The TNTs were loaded with alendronate and ibuprofen via vacuum drying method and the release properties from the nanotubes were detected in phosphate buffer solution (PBS). The samples were characterized by field emission scanning electron microscopy, X-ray diffraction, and UV-Vis spectrophotometer. The data show that copper is successfully doped to the nanotube surface by hydrothermal treatment, and the optimum hydrothermal treatment conditions are 200°C, 0.5h. The drug loading capacity of the modified sample increased obviously, whether it was hydrophilic or hydrophobic. Meanwhile, the modified nanotubes release more slowly in the later stage. This approach provides an alternative to tailor the surface of TNTs and offer considerable propects for diverse biomedical applications.

Abstract: ZnO with different morphologies were formed on Zn foils immersed in various concentrations of CuSO4 solutions. Then the specimens were heated at temperature of 200~600°C in air for 3h. The morphologies of as-prepared specimens were characterized by a scanning electron microscope (SEM). Water wetting angles on the specimens were measured. The results indicate that the morphologies of ZnO on the Zn foils relate to the CuSO4 concentration of in solutions. The morphologies on the specimens with dual-scale (nanoand micro) structure have higher wetting angles than those with flat structure. The water wetting angles can reduce with the increase in annealing temperatures of immersed specimens. The water wetting angles increase with keeping immersed specimens at room temperatures. The change of the wetting angle is explained by absorption of organic carbon on specimen surface and the geometric structure of the surface.

Abstract: Cd_xZn_1-xTe is a promising material for tandem solar cells with a continuously adjustable band gap from 1.45eV to 2.26eV, but p-type Cd_xZn_1-xTe with higher carrier density is rarely reported. Cd_xZn_1-xTe thin films with Cu layers were deposited by vacuum co-evaporation in sequence and annealed in low vacuum in this paper. The compositional, structural, morphological, electrical and optical properties were studied. The results show that zinc-blended Cd_0.4Zn_0.6Te films with (111) preferred orientation were fabricated. Conduction type of annealed Cd_xZn_1-xTe films with Cu layers will change from intrinsic to p-type. Cu doped Cd_xZn_1-xTe thin films with carrier density of 10¹⁸~10¹⁹cm^-3 and the band-gap of 1.89~1.93eV can be obtained. It demonstrates that Cu is an effective p-type dopant for Cd_xZn_1-xTe thin films.

Abstract: This paper described the preparation of Cu loaded TiO₂ nanotube arrays. Firstly, TiO₂ nanotube arrays were formed by anodization. Afterwards, the formed nanotube arrays were incorporated with Cu by wet impregnation method. The soaking time and concentration were varied to obtain an optimum set of parameter for Cu incorporation in TiO₂ nanotubes. After anodization, all samples were annealed at 400°C for 4 hours to obtain anatase phase. The nanotube arrays were characterized by field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD) and x-ray photoelectron spectra (XPS). An average diameter 63.02 nm and length 12.15µm were obtained for TiO₂ nanotubes. The photocatalytic activity of these nanotubes were investigated with methyl orange (MO) and the TiO₂ nanotube prepared in 0.01M of Cu (NO₃)₂ solution within 3 hours demonstrates the highest photocatalytic activity with 83.6% degradation of methyl orange. Keywords: copper doping, wet impregnation, photocatalytic activity

Abstract: Cu-doped TiO₂ photocatalysts were synthesized by a homogeneous hydrolysis and low temperature crystallization method using tetrabutyl titanate as the titanium source and cupric acetate as the doping agent. The phase structure, composition and morphology of the product were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS) and Brunauer-Emmett-Teller surface area analysis (BET). The XRD results confirmed that the crystalline phase of all prepared samples was anatase-type TiO₂. SEM results showed that the Cu-doped TiO₂ were composed of spherical particles with particle diameter smaller than 20 nm. Furthermore, the photocatalytic activity of the Cu-doped TiO₂ catalysts were evaluated based on the photocatalytic degradation of methyl orange (MO) in aqueous solution. The results showed that Cu-doped TiO₂ had the higher visible-light-induced catalytic activity than the commercial P25 TiO₂ powder. The copper content in Cu-doped TiO₂ had obvious effect on the visible-light-induced catalytic activity, and the degradation rate of MO could reach 33.7% using Cu-doped TiO₂ with a doping level of 1.0 mol% Cu as a photocatalyst under the visible light irradiation for 3 hours.

Abstract: Copper doped TiO2 nanoparticles were synthesized by hydrolysis of tetrabutyl titanate (Ti(OBu)4) and copper nitrate (Cu(NO3)2) in water-in-oil (W/O) microemulsions, consisting of water, Triton X-100, n-hexanol, cyclohexane and water. In this W/O system, Trinton X-100, n-hexanol and cyclohexane were used as surfactant, co-surfactant and organic solvent, respectively. The prepared nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). The results show that the Cu-doped TiO2 nanoparticles synthesized by this method have a good dispersion character and relatively small sizes of about 80 nm. The XRD results show that the calcination temperature greatly influences the crystallization transformation. When calcined below 550 °C, the prepared sample is composed of anatase structure. When the calcination temperature increases to 650 °C, rutile phase appears besides the anatase phase. While doping amount has little effects on crystal phase. FTIR analysis indicates that most of the contained water and the residual organic surfactants can be removed by calcination.