Search

Abstract: Bi-doped hollow titania spheres were prepared using carbon spheres as template and Bi-doped titania nanoparticles as building blocks. The Bi-doped titania nanoparticles were synthesized at low temperature. The prepared hollow spheres were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), UV–vis diffuse reflectance spectrum (DRS) and X-ray photoelectron spectroscopy (XPS). The effects of Bi content on the physical structure and photocatalytic activity of doped hollow titania sphere samples were investigated. Results showed that there was an optimal Bi-doped content (4%) for the photocatalytic degradation of methylene blue (MB). [Copyright &y& Elsevier]

Abstract: N-doped TiO2 nanotube arrays (NTN) were prepared by anodization and dip-calcination method. Hydrazine hydrate was used as nitrogen source. The surface morphology of samples was characterized by SEM. It showed that the mean size of inner diameter was 65nm and wall thickness was 15nm for NTN. The ordered TiO2 nanotube arrays on Ti substrate can sustain the impact of doping process and post-heat treatment. The atomic ratio of N/Ti was 8/25, which was calculated by EDX. Photoelectrochemical property of NTN was examined by anodic photocurrent response. Results indicated the photocurrent of NTN was nearly twice as that of non-doped TiO2 nanotube arrays (TN). Photocatalytic activity of NTN was investigated by degrading dye X-3B under visible light. As a result, 99% of X-3B was decomposed by NTN in 105min, while that of TN was 59%. [Copyright &y& Elsevier]

Abstract: A novel photocatalyst (Ce, C-codoped titania) was synthesized through a modified sol–gel method under mild condition. The as-prepared sample was investigated by XRD, SEM, DRS and XPS. It was found that the as-prepared photocatalyst was composed of spheroidal particles, which were smaller than undoped ones. The absorbance spectrum of Ce, C-codoped TiO2 exhibited significant red-shift to visible region. It can be ascribed to appearance of a new electronic state in the middle of the TiO2 band-gap. Furthermore, cerium doping could slow the radiative recombination process of photogenerated electrons and holes in TiO2. Accordingly, for degradation of dye Reactive Brillint Red X-3B (C.I. reactive red 2) under visible light, the photocatalytic activity of Ce, C-codoped TiO2 improved much compared to other samples (C-doped TiO2, undoped TiO2 and P25). [Copyright &y& Elsevier]

Abstract: Bi2O3–TiO2 composite films were synthesized by a sol–gel method under mild condition (i.e. low temperature and ambient pressure). The as-prepared films were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, infrared spectra and fluorescence spectra. The results showed that Bi2O3–TiO2 composite films were composed of anatase titania and Bi2O3. TiO2 particles were deposited on the surface of Bi2O3 to form uniform film. Incorporating Bi2O3 with TiO2 leads to increased surface OH group density. All Bi2O3–TiO2 composite films exhibited higher photocatalytic activity compared with pure TiO2 under solar irradiation, while the film with Bi/Ti atomic ratio of 1.25% showed the highest photocatalytic activity. Furthermore, the as-prepared films can be reused with little photocatalytic activity decreasing. Without any further treatment besides rinsing, the photocatalytic activity of Bi2O3–TiO2 (1.25%) films was still higher than 77% after six-cycle utilization. [Copyright &y& Elsevier]

Abstract: Anatase titania-activated carbon composite film was prepared by a simple method at low temperature (75°C at most). The film was characterized by XRD, SEM and BET analysis. Results showed that the composite film was porous because it formed a nano-micro structure. The photocatalytic activity of the composite film was determined by degradation of 4-cholophenol (4-CP) under UV irradiation, and was compared to pure titania film and P25 film. It exhibited that the photocatalytic activity of composite film enhanced a lot. The recycle ability of the composite film was also investigated. The degradation ratio which was still higher than 85% after 5 cycles, decreased only 3% compared to the first cycle. [Copyright &y& Elsevier]

Abstract: A novel and simple method for preparing F-doped anatase TiO2 (defined as FTO) film with high photocatalytic activity was developed using titanium-n-butoxide and NH4F as TiO2 and fluorine precursors under mild condition, i.e. low temperature (lower than 373K) and ambient pressure. The prepared samples were characterized by XRD, SEM, X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectrum (DRS), photoluminescence spectrum (PL) and TG–DSC analysis. The photocatalytic activity was evaluated by decomposing X-3B under artificial solar light. The results showed that the crystallinity of TiO2 was improved by F-doping. F− ions can prevent the grain growth, and the transformation of anatase to rutile phase was also inhibited. The doped fluorine atoms existed in two chemical forms, and the ones incorporated into TiO2 lattice might take a positive role in photocatalysis. Compared with surface fluorination samples, FTO film exhibited better photocatalytic activity. The high photocatalytic activity of FTO may due to extrinsic absorption through the creation of oxygen vacancies rather than the excitation of the intrinsic absorption band of bulk TiO2. Furthermore, the FTO can be recycled with little photocatalytic activity depression. Without any further treatment besides rinsing, after 6 recycle utilization, the photocatalytic activity of FTO film was still higher than 79%. [Copyright &y& Elsevier]

This very paper is focusing on the preparation and characterization of silicon nano-structures prepared via hydrothermal growth technology. The morphology and the structure given by the transmission electron microscope indicates that the silicon nanostructures are nano-crystallites, nano-wires and even nano-tubes, all of which are coated with the silica layer. Luminescence performance investigation presents that there is a strong photoluminescence emission at about 400nm and the weak one at about 700nm. The controllability over the thickness of the silica coating and the size of silicon nano-core were achieved via the post HF etching procedure or done by prolonging the growth period, respectively. Accordingly, the mechanism of photoluminescence emissions is discussed, which proposes that both the surface radiative recombination center be responsible for 400nm emission, and so does the confinement effect of the optical phonon for 700nm. It might, also, come to that the Si-Hx bonds on the surface of the exorbitantly HF etched SiNS samples probably gives rise to the 390nm emission. [Copyright &y& Elsevier]