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Polycrystalline mixed-phase TiO2nanofibers embedded with 2.0% w/v Ag nanoparticles was prepared by the electrospinning technique. Calcination of dry Ag nanoparticles-titanium (IV) isopropoxide/PVP electrospun nanofiber mats in air at for 24 h yielded polycrystalline TiO2/Ag nanofibers. The morphology and distribution of silver nanoparticles were observed by transmission electron microscopy (TEM), scanning TEM (STEM), and high-angle annular dark-field (HAADF) imaging. Mixed-phase anatase and rutile TiO2nanofibers were produced with Ag nanoparticles. High-resolution TEM lattice-fringe measurements showed good agreement with Ag (111), anatase (101), and rutile (110) phases. The photocatalytic activity of TiO2/Ag nanofibers was compared to the photocatalytic activity of pure TiO2nanofibers by studying the photodegradation of methyl red dye under UV light irradiation, in a photoreactor. UV-visible absorbance spectra showed that the rate of decay of the dye in case of photodegradation by TiO2/Ag nanofibers was 10.3 times higher than that by pure TiO2nanofibers. The retaining of the fiber morphology along with the increased surface area due to the addition of Ag nanoparticles can be believed to enhance the photocatalytic oxidation of methyl red dye.

In this paper, the morphology, chemical composition and reactivity of MCM-48 powders impregnated with Ni , Mo or both toward hydrodesulphurization (HDS) of thiophene were characterized. The reactivity of the catalyst was quantitatively compared with a standard industrial catalyst (from HaldorTopsoe, Denmark) and a novel WS 2 nanotube-based catalysts (from R. Tenne, Israel). Morphology and chemical composition were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and EDX elemental maps. Reactivity was determined in a gas-chromatograph based mini flow reactor using thiophene as a probe molecule. The sulfided MCM-48 supported Mo catalyst showed the largest HDS activity with turnover frequencies (TOF) about half as large as for the commercial system under the test conditions used here. Presulfiding did increase activity of all MCM-48 catalysts.

Electrospinning is an electrical, jet-based method of fabricating nanofibers that involves the application of a very high electrostatic force on the capillary containing the polymer solution or polymer-melt. The fibers are created by an electrically charged jet of the polymer solution, which can be collected on the surface of a grounded template. The incorporation of metal nanoparticles produces functional nanofibers. Among the noble metal nanoparticles, silver nanoparticles are promising because they have electronic and catalytic properties [1].Poly(vinyl pyrrolidone) (PVP) and amorphous TiO 2 nanofibers with Ag nanoparticles were prepared by electrospinning precursor solutions of PVP and titanium isopropoxide (TiIP) with varying concentrations of Ag nanoparticles in ethanol (Fig. 1A). Ag nanoparticles were prepared by the polyol synthesis. The morphology and distribution of silver nanoparticles were observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Titania nanofibers with Ag nanoparticles were annealed at 510 o C to produce crystalline anatase TiO 2 nanofibers with Ag nanoparticles (Fig. 1B). Lattice fringe measurements from high-resolution TEM images showed the presence of Ag nanoparticles in its elemental form, and TiO 2 as a combination of rutile and anatase phases. This result was also supported by EDX.Photocatalytic effect of pure TiO 2 , and TiO 2 /Ag nanofibers was studied by tracking the decay of methyl red dye in a photocatalytic reaction, under ultraviolet light (Fig. 2). Methyl red dye decayed by 24% by the activity of pure TiO 2 , and 30% by TiO 2 /Ag nanofibers, in a span of 265 min (Fig. 3). This increase in the dye-decay can be attributed to the presence of Ag nanoparticles in the nanocrystalline TiO 2 fibers, which enhanced the photocatalytic activity of titania. We propose to perform high-angle annular dark-field (HAADF) on the TiO 2 /Ag nanofibers to further characterize the fibers and to understand the mechanism behind the enhanced photocatalytic effect.

Electrospinning is an electrical, jet-based method of fabricating nanofibers that involves the application of a very high electrostatic force on the capillary containing the polymer solution or polymer-melt. The fibers are created by an electrically charged jet of the polymer solution, which can be collected on the surface of a grounded template. The incorporation of metal nanoparticles produces functional nanofibers. Among the noble metal nanoparticles, gold nanoparticles are promising because they have electronic, magnetic, optical and catalytic properties [1].The solution for electrospinning poly(vinyl pyrrolidone) (PVP) nanofibers was prepared by mixing varying concentrations of 10 nm Au nanoparticles-colloidal solution and PVP (average M.W.