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Heterojunctioned architectures were facilely fabricated using hydrothermally treated electrospun TiO 2 nanofibers in an alkaline Sr(NO 3 ) 2 precursor solution in an electronic oven. TiO 2 on the fiber surface was partially dissolved into Ti 4+ to react with Sr 2+ in favor of the nucleation of SrTiO 3 on TiO 2 nanofibers, and thus a heterojunction was formed between SrTiO 3 and TiO 2 , which will benefit the improvement of photocatalytic activity. And then a multifunctional membrane was created by functionalizing the surface of commercial cellulose acetate (CA) membrane with heterojunctioned SrTiO 3 /TiO 2 nanofibers. This newly structured membrane exhibited excellent water purification performances in a concurrent photocatalytic membrane filtration system under the irradiation of UV light, because it is able to integrate the advantages of photocatalysis and membrane filtration while minimizes their disadvantages. The high water purification performances in terms of high photodegradation ability and high permeate flux are attributed to the high photocatalytic activity of heterojunctioned SrTiO 3 /TiO 2 nanofibers architectures and their structured porous functional layer favorable for fast water pass through. [ABSTRACT FROM AUTHOR]

Abstract: Here, hierarchically meso/nanoporous TiO2 was successfully fabricated by a facile and efficient hydrolysis and calcination method using Ti(OC4H9)4 and K2S2O8 as precursors. The hydrosol was firstly prepared by drop-wise adding ethanol dissolved Ti(OC4H9)4 solution into acetone dissolved K2S2O8 solution under a vigorous stirring and heating condition. After being sufficiently hydrolyzed, the hydrosol was calcined to promote the crystallization of TiO2 and successfully dope S and C on TiO2. The calcination temperature significantly affects the doping of S and C on TiO2, crystallization of TiO2, formation of hierarchically meso/nanoporous structure of TiO2 and its light absorption capability. The S- and C-codoped TiO2 exhibits high photocatalytic H2 generation efficiency in a water/methanol sacrificial reagent system under the irradiation of UV light. The high photocatalytic efficiency is dependent on the comprehensively competing effects of the codoping of S and C, crystallization, specific surface area and light absorption capability. The S- and C-codoped TiO2 calcined at 600°C demonstrates the highest photocatalytic H2 generation efficiency, which is ascribed to the balanced synergy of the abovementioned factors. [Copyright &y& Elsevier]

Abstract: The effect of fabrication method on the properties of hierarchical 3D TiO2 nanostructures was investigated by employing and developing both hydrothermal method and calcination method to synthesize hierarchical 3D TiO2 nanorod spheres in this study. A comprehensive comparison in terms of morphologies, crystallization, specific surface areas, light absorption capabilities, and photoluminescence spectrum was conducted between 3D TiO2 nanorod spheres synthesized via hydrothermal method and that synthesized via calcination method. A better photocatalytic activity was demonstrated over the TiO2 nanorod spheres synthesized through calcination method. This was ascribed to the better crystallization and monodispersion of the hierarchical 3D TiO2 nanorod spheres resulted from the calcination method; thus rendering it with more superior characteristics such as larger specific surface area, enhanced light absorption capability and faster transfer of electrons which suppress the recombination of photogenerated electrons and holes. This study is thus significant not only in promoting the development of hierarchical 3D TiO2 nanorod spheres via different methods, but also in revealing the effect of fabrication method on the photocatalytic activity of hierarchical 3D TiO2 nanorod spheres. The calcination method is proposed to be a facile and promising method for scale-up production of the hierarchical 3D TiO2 nanorod spheres with high photocatalytic activity for efficient pollutants degradation. [Copyright &y& Elsevier]

Abstract: Through hydrothermally growing SrTiO3 cubics on the surface of electrospun TiO2 nanofibers, SrTiO3/TiO2 nanofibers heterostructures were successfully fabricated in the present study. This process is able to ensure uniform distribution of SrTiO3 on the surface of TiO2 nanofibers and lead to close contact between SrTiO3 and TiO2, which is beneficial for the fast separation of photogenerated electrons and holes so as to suppress the recombination of photogenerated electrons and holes at the interphase of SrTiO3 and TiO2. Besides this, the long 1D fibrous structure easy for electron transfer, the hierarchical structure promoting mass transfer and allowing more light reflection and absorption, and the large specific surface area providing more reactions sites to facilitate the reactants to desired oxidation places all together create a synergistic effect on improving the photocatalytic activity of the hierarchical SrTiO3/TiO2 nanofibers heterostructures. Under the irradiation of UV light, in a water/methanol sacrificial reagent system, the SrTiO3/TiO2 nanofibers heterostructures generate five times more H2 than bare TiO2 nanofibers because of its high photocatalytic activity. [Copyright &y& Elsevier]

Cylinder- and bamboo-shaped boron nitride nanotubes (BNNTs) have been synthesized in large scale via a facile chemical vapor reaction route using ammonia borane as a precursor. The structure and chemical composition of the as-synthesized BNNTs are extensively characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and selected-area electron diffraction. The cylinder-shaped BNNTs have an average diameter of about 100 nm and length of hundreds of microns, while the bamboo-shaped BNNTs are 100-500 nm in diameter with length up to tens of microns. The formation mechanism of the BNNTs has been explored on the basis of our experimental observations and a growth model has been proposed accordingly. Ultraviolet-visible and cathodoluminescence spectroscopic analyses are performed on the BNNTs. Strong ultraviolet emissions are detected on both morphologies of BNNTs. The band gap of the BNNTs are around 5.82 eV and nearly unaffected by tube morphology. There exist two intermediate bands in the band gap of BNNTs, which could be distinguishably assigned to structural defects and chemical impurities. [ABSTRACT FROM AUTHOR]

Abstract: One-dimensional mesoporous TiO2 nanotube (TNT) with large specific surface area was successfully fabricated, and employed in removal of Acid Orange 7 (AO7) via adsorption and heterogeneous photocatalysis. As compared to its precursor, P25 (Degussa), TNT exhibited superior adsorption ability and photocatalytic activity. It was found that the amount of adsorbed dye over TNT surface was critical to the photodegradation efficiency of AO7, and adsorption was further controlled by solution pH and co-existing ions. With an increase in pH, adsorption of AO7 decreased rapidly, and adsorption behavior transformed from monolayer adsorption to asymmetric physisorption. Under low pH conditions, multivalent anions in high concentrations severely limited AO7 adsorption on TNT; whereas the increase of pH led to a less severe inhibition of the adsorption. On the other hand, multivalent cations seem to facilitate adsorption, regardless of pH conditions. Adsorption mechanism and photodegradation kinetics of AO7 on TNT were also discussed in the paper in view of paving the way for efficient dye wastewater treatment with the application of TNT photocatalyst. [Copyright &y& Elsevier]