Hybrid Carbon Spherogels: Carbon Encapsulation of Nano-Titania

Extraordinarily homogeneous, freestanding titania-loaded carbon spherogels can be obtained using Ti(acac)2(OiPr)2 in the polystyrene sphere templated resorcinol-formaldehyde gelation. Thereby, a distinct, crystalline titania layer is achieved inside every hollow sphere...

Template-Free and Surfactant-Free Synthesis of Selective Multi-Oxide-Coated Ag Nanowires Enabling Tunable Surface Plasmon Resonance

Without using templates, seeds and surfactants, this study successfully prepared multi-oxide-layer coated Ag nanowires that enable tunable surface plasmon resonance without size or shape changes. A spontaneously grown ultra-thin titania layer onto the Ag nanowire surface causes a shift in surface plasmon resonance towards low energy (high wavelength) and also acts as a preferential site for the subsequent deposition of various oxides, e.g., TiO2 and CeO2. The difference in refractive indices results in further plasmonic resonance shifts. This verifies that the surface plasma resonance wavelength of one-dimensional nanostructures can be adjusted using refractive indices and shell oxide thickness design.

Photoelectrocatalytic Hydrogen Production Using a TiO2/WO3 Bilayer Photocatalyst in the Presence of Ethanol as a Fuel

Photoelectrocatalytic hydrogen production was studied by using a photoelectrochemical cell where the photoanode was made by depositing on FTO electrodes either a nanoparticulate WO3 film alone or a bilayer film made of nanoparticulate WO3 at the bottom covered with a nanoparticulate TiO2 film on the top. Both the electric current and the hydrogen produced by the photoelectrocatalysis cell substantially increased by adding the top titania layer. The presence of this layer did not affect the current-voltage characteristics of the cell (besides the increase of the current density). This was an indication that the flow of electrons in the combined semiconductor photoanode was through the WO3 layer. The increase of the current was mainly attributed to the passivation of the surface recombination sites on WO3 contributing to the limitation of charge recombination mechanisms. In addition, the top titania layer may have contributed to photon absorption by back scattering of light and thus by enhancement of light absorption by WO3. Relatively high charge densities were recorded, owing both to the improvement of the photoanode by the combined photocatalyst and to the presence of ethanol as the sacrificial agent (fuel), which affected the recorded current by “current doubling” phenomena. Hydrogen was produced under electric bias using a simple cathode electrode made of carbon paper carrying carbon black as the electrocatalyst. This electrode gave a Faradaic efficiency of 58% for hydrogen production.

Analysis of Thermal Treatment Zirconia as Spacer Layer on Dye-Sensitized Solar Cell (DSSC) Performance with Monolithic Structure

Monolithic dye-sensitized solar cells (DSSC) offer the prospect of lower material cost and require a simpler manufacturing process compared with conventional DSSC. Fabricated on a single fluorine tin oxide (FTO) glass substrate consists of a nanoporous TiO2 photoanode layer, a ZrO2 spacer layer, a carbon counter electrode layer, a dye, and an electrolyte. The spacer layer on the monolithic DSSC serves as electrolyte storage and insulating layer to separate between photoanode and counter electrode. Zirconia is often used as a spacer because it has high temperature resistant properties, high dielectric constant and adhesive as an insulator that has band gap between 5-6 eV. The effects of the thermal treatment of zirconia layer as a spacer electrolyte on the performance of monolithic DSSC have been investigated. The cell’s performance increases with the sintering temperature as well as indicated by the decreased in particle size and increased in quantum efficiency in the absorption region of the titania layer. Co-sintering treatment tends to drastically reduce cell’s performance. The highest performance was obtained at a temperature sintering of 500o C with an PCE of 0.22%, Isc = 0.16 mA and Voc = 0.71 V.

Improvement of the photovoltaic parameters of perovskite solar cells using a reduced-graphene-oxide-modified titania layer and soluble copper phthalocyanine as a hole transporter

Graphene modified mesoporous titania for perovskite solar cells.

Deposition of a titania layer on spherical porous silica particles and their nanostructure-induced vapor sensing properties

A porous titania layer with different nanostructures was formed on monodispersed nanoporous silica spherical particles to demonstrate unique sensitive/selective vapor sensing properties.