Jian Ling Zhao

Photoelectrochemical Activity of Cu-Loaded TiO2 Nanotube Arrays by AC Electrodeposition

This work presents a novel approach for preparing Cu-loaded TiO2 nanotube arrays through alternating current electrodeposition. The Cu content loaded on the arrays was controlled by changing the concentration of Cu (NO3)2 solution, deposition voltage and time. The surface morphology and crystal structure of Cu-loaded TiO2 nanotube arrays were characterized by scanning electron microscopy (SEM) and the X-ray diffraction (XRD). The effects of Cu content on the photoelectrochemical property were studied in detail. Results show that Cu-loaded TiO2 nanotube arrays have evidently enhanced photoelectrochemical activity. The photocurrent of Cu-loaded TiO2 nanotube arrays prepared in 0.00625 mol/L Cu (NO3)2 solution at 12 V for 20 seconds was 5.7 and 2.3 times as that of unloaded TiO2 nanotube arrays under visible and UV radiation, respectively.

Effect of Ti:Fe Ratios on the Phase Structures and Properties of Iron Titanium Oxides

Iron titanium oxides with different Ti:Fe ratios (molar ratio: 3:1, 2:1, 1:1, 1:2, 1:3) have been prepared by chemical coprecipitation process. The structures and properties of the samples have been characterized by X-ray diffraction, vibrating sample magnetometer and UV-vis spectrophotometer. Results show that the samples annealed at 460 °C have poor crystallinity. At 550 °C, the crystallinity of all the samples increased strikingly. The iron titanium oxides contained anatase TiO2, rutile TiO2, α-Fe2O3 and/or Fe2TiO5. Ti:Fe ratios have a great influence on the detailed phase compositions of each sample. The iron titanium oxides exhibited paramagnetism and the intensity of magnetization increased with the increasing content of Fe. Band gap energies of the oxides changed slightly with increasing content of Fe with an average value of 2.0 eV, obviously lower than that of TiO2 .

Synthesis, crystal structure, and characterizations of a (6,3)-connected coordination polymer based on cadmium(II) and nickel(II)

A novel heteronuclear coordination polymer Cd(1,3-μ-SCN)6Ni2(C2H8N2)2(H2O)2 (I) has been prepared and characterized by elemental analysis, EDS analysis, PXRD and IR spectrum and single-crystal X-ray diffraction. The single-crystal X-ray diffraction analysis revealed that compound I crystallizes in a monoclinic system of space group C2/m with a = 19.427(8), b = 9.622(3), c = 7.261(3) Å, β = 105.383(10)°. The compound exhibits a (6,3)-connected two-dimensional layer which is built up from the strict alternation of 6-connected {CdS6} octahedra and 3-connected {NiON5} octahedra.

Photoelectrochemical Properties of NaTaO3 Microrods Prepared by Anodization

In this work, sodium tantalate (NaTaO3) microrods were successfully prepared by anodic oxidation of tantalum in 30% NaOH electrolyte. The morphology and structure of microrods were characterized by scanning electronic microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD), respectively. SEM analysis shows the formation of microrods with an average length of 12.8 μm and a diameter of 2.3 μm. XRD analysis reveals that the as-prepared microrods are amorphous. After annealing in nitrogen at 800 °C, the amorphous NaTaO3 microrods transform into orthorhombic structure. Experimental results indicate that the microrods have a high photoelectrochemical property. The possible formation mechanism of NaTaO3 microrods has also been discussed.

Enhanced Visible Light Activity of Ag-Loaded TiO2 Nanotube Arrays by AC Electrodeposition

In this work, highly-ordered TiO2 nanotube arrays were prepared by constant-voltage anodization, followed by electrodeposition of Ag to obtain Ag-loaded TiO2 (Ag-TiO2) nanotube arrays via alternating current (AC) process. The results of SEM and XRD show that the morphology and crystal structure of Ag-TiO2 layer depend greatly on the electrodeposition parameters. Ag-TiO2 nanotube arrays prepared in 2.5 mmol/L AgNO3 solution by electrodeposition with applied voltage of 12 V for 1 minute performed the best photoelectrochemical current response and photocatalystic activity. The photocurrent density of Ag-TiO2 is 43.32 μA/cm2 under sunlight irradiation (70 mW/cm2), which is 4.2 times as that of unloaded TiO2 nanotube arrays. Methyl orange (MO) degradation rate with the Ag-TiO2 nanotube arrays achieves 52.13% after 90 min sunlight irradiation which is obvious higher than that of TiO2 nanotube arrays. The mechanism of enhancing photoelectrochemical activity of decorating titania with Ag has also been discussed in the view of energy band theory.

Fabrication and Mechanism of Titania Nanotube Arrays by Anodization in DMSO Electrolyte

Titania nanotube arrays were synthesized via anodic oxidization of titanium foil in dimethyl sulfoxide (DMSO) solution containing 2 wt% HF and 3 wt% H2O at 40 V. The microstructure of the arrays was characterized with scanning electron microscopy (SEM). The results show that morphology of titania nanotube arrays is evidently influenced by the anodization time, and with the extension of oxidation time, the better morphology could be obtained. The possible formation mechanism of titania nanotube arrays has been discussed.

Autothermal Gelation Synthesis of Uniform Titania Nanoparticles

Titania nanoparticles were successfully synthesized through an easily controlled and simple autothermal gelation process. Effects of H2O2 concentrations, solvent quantity and dissolving temperature were investigated in detail. DSC–TGA and XRD analysis showed that the synthesized TiO2 nanoparticles were in anatase phase at 400°C and in rutile phase at 650°C. TEM image indicated that the titania nanoparticles were uniform and approximately spherical, the average grain size of the product was about 20 nm.

Self-Organized Zirconia Nanotube Arrays Prepared by Anodization

The zirconia nanotube arrays on zirconium substrates were formed in (NH4)2SO4 electrolytes containing different concentrations of NH4F (0.5-2.0 wt%). Highly self-organized zirconia nanotubes can be formed with a diameter ranging from 15 nm to 144 nm and a length of 32 μm. The morphology of the nanotubes was strongly influenced by the applied voltages and electrolyte concentrations. Electrochemical testing and scanning electron microscope observation indicated the nanotubes were formed due to the competition of zirconia formation and dissolution under the assistance of electric field.

Self-Organized High Aspect Ratios Titanium Oxide Nanotube Arrays Prepared by Anodization

The self-organized nanotube arrays were fabricated in glycerol electrolyte containing different additives, such as deionized water or ethylene glycol. The effects of anodization conditions, including anodic voltage, electrolyte viscosity, additives and ion concentration on the pores size and morphology were studied. Combined with preoxidation process, high aspect ratio titania nanotube arrays were formed rapidly in glycerol and saturated NaF solutions at 60 V for 1 h. SEM observation showed that a film with the thickness of about 10μm was obtained. A possible mechanism of the nanotubes growth was presented.

Synthesis, Characterization and Electrical Properties of Barium Titanate Films Fabricated by Hydrothermal Method

BaTiO3 films with a thickness up to 3 μm were fabricated under the hydrothermal conditions. It was found that the crystallinity of BaTiO3 increases with the concentration of Ba(OH)2 solutions. Along with the increasing of time, the crystallinity of BaTiO3 increases, reaches the maximum value and then decreases. The measured values of remanent polarization (Pr) and coercive field (Ec) are 1.74μC/cm2 and 24KV/cm. The leakage of the films at 1V is 10-7A/cm2. The dielectric constant and loss tangent of hydrothermal derived BaTiO3 film at a frequency of 1 KHz were 600 and 0.2, respectively.