TiO2 Nanosheet Films Research Articles

Fabrication, characterization, and photocatalytic activity of double-layer TiO2 nanosheet films

The double-layer TiO2 nanosheet films have been deposited on Si substrate by a liquid-phase deposition method using ZnO nanosheets as the template. The initial morphology of the ZnO nanosheet templates is maintained after the TiO2 deposition. The TiO2 nanosheets are uniformly distributed widely and grown perpendicularly to the substrate. The TiO2 nanosheets are of anatase phase with the outside thickness of ~220–380nm. The growth mechanism for the formation of TiO2 nanosheet films is investigated. Experimentally, it shows that the TiO2 nanosheet films have highly photocatalytic activities for the decomposition of azo dye C. I. reactive yellow 15.

Au/TiO2/Au as a Plasmonic Coupling Photocatalyst

The enhanced near-field amplitude of localized surface plasmon resonance in the proximity of metal nanoparticles can boost the photocatalytic activity of the neighboring semiconductor, which has been proven and has attracted wide interest recently. Since the plasmon resonance energy strongly depends on the metal particle size and shape, interparticle spacing, and dielectric property of the surrounding medium, it is available to improve the photocatalytic activity of the neighboring semiconductor by designing and synthesizing targeted metal nanoparticles or assembled nanostructures. In this paper, we propose a Au/TiO2/Au nanostructure with the thickness of the middle layer TiO2 nanosheets around 5 nm, which satisfies the distance needed for the coupling effect between the opposite and nearly touching Au nanoparticles, and thus, it can be used as a “plasmonic coupling photocatalyst”. Compared with the bare TiO2 nanosheet films, the photocurrent density of this favorable nanostructure exhibited a significant...

Yolk@shell anatase TiO2 hierarchical microspheres with exposed {001} facets for high-performance dye sensitized solar cells

We report a facile, template-free and nontoxic one-pot solvothermal route for synthesizing submicrometer-sized yolk@shell hierarchical spheres, which possess a permeable shell self-assembled by ultrathin anatase TiO2 nanosheets (NSs) with nearly 90% of exposed {001} facets and mesoporous inner sphere with a high specific surface area. Compared to the {001} faceted TiO2 NSs and standard Degussa P25, the anatase TiO2 yolk@shell hierarchical spheres (TiO2 YSHSs) were obtained with surface area up to 245.1 m2 g−1 and their submicrometer scale simultaneously promoted light scattering in the visible region. A light to electricity conversion efficiency (η) of 6.01% was achieved for the DSSCs with TiO2 YSHSs as its photoanode, under 100 mW cm−2 illumination, indicating 49.9% and 34.8% increases compared to the DSSCs with TiO2 NSs (4.01%) and the standard Degussa P25 (4.46%) as photoanodes, respectively. The enhancement can be mainly attributed to the higher dye loading on TiO2 YSHSs (4.35 × 10−5 mol cm−2) than that of TiO2 NSs (3.14 × 10−5 mol cm−2) and P25 (3.32 × 10−5 mol cm−2); longer lifetime of the injected electrons in TiO2 YSHSs film (65.79 ms) than that of in TiO2 NSs film (57.90 ms); and the good capability of light scattering of TiO2 YSHSs in visible light region, which are confirmed by UV-vis spectrophotometer and electrochemical impedance spectroscopy (EIS). The growth mechanism of the TiO2 YSHSs has also been investigated in detail.

Hydrothermal Growth of Layered Titanate Nanosheet Arrays on Titanium Foil and Their Topotactic Transformation to Heterostructured TiO2 Photocatalysts

Layered titanate nanostructures have been recognized as an important intermediate in preparing TiO2 nanostructures due to their availability in various morphologies, among which ultrathin nanosheets have attracted particular attention due to their unique properties arising from their high surface area and confined thickness in nanoscale. Herein, we report a simple approach to fabricate heterostructured TiO2 nanosheet array film by (1) hydrothermal growth of sodium trititanate nanosheet array on Ti foil in alkaline solution, (2) ion exchange of Na+ in titanate naosheet with H+, and (3) topotactical transformation into TiO2 nanosheet via thermal annealing. XRD and Raman as well as HRTEM analyses proved the formation of a novel anatase/TiO2(B) heterostructured nanosheet array with coherent interface between the two phases, which exhibited superior photocatalytic efficiency under UV illumination as compared with the relevant commercial products P25 and anode oxidized TiO2 nanotube film of the same thickness but with greater mass of photocatalyst. The high photocatalytic activity of the TiO2 nanosheet array film can be ascribed to the synergistic effect of large surface area and high crystallinity as well as heterojunction between TiO2(B) and anatase phase.

Anatase TiO2 nanosheets with exposed (001) facets: improved photoelectric conversion efficiency in dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) are fabricated based on anatase TiO(2) nanosheets (TiO(2)-NSs) with exposed {001} facets, which were obtained by a simple one-pot hydrothermal route using HF as a morphology controlling agent and Ti(OC(4)H(9))(4) as precursor. The prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis absorption spectroscopy and N(2) adsorption-desorption isotherms. The photoelectric conversion performances of TiO(2)-NSs solar cells are also compared with TiO(2) nanoparticles (TiO(2)-NPs) and commercial-grade Degussa P25 TiO(2) nanoparticle (P25) solar cells at the same film thickness, and their photoelectric conversion efficiencies (η) are 4.56, 4.24 and 3.64%, respectively. The enhanced performance of the TiO(2)-NS solar cell is due to their good crystallization, high pore volume, large particle size and enhanced light scattering. The prepared TiO(2) nanosheet film electrode should also find wide-ranging potential applications in various fields including photocatalysis, catalysis, electrochemistry, separation, purification and so on.

Preparation and properties of Cu-grafted transparent TiO 2-nanosheet thin films

Transparent TiO 2 nanosheet thin films were prepared using layer-by-layer method with poly(diallyldimethylammonium chloride) as a counter polymer. The possibility of photocatalysis by the light in the long wavelength range was examined by grafting Cu on the film. Photocatalytic decomposition activity for gaseous 2-propanol under UV illumination without light for electron excitation of TiO 2 nanosheet was increased by Cu grafting, suggesting that the interfacial charge transfer mechanism is effective also for nanosheet films.

Synthesis of a Perpendicular TiO2 Nanosheet Film with the Superhydrophilic Property without UV Irradiation

A method was developed for preparing perpendicular TiO2 nanosheet films from titanate nanosheet films produced on a titanium metal sheet by hydrothermal treatment with aqueous urea. The method is based on the consideration of some important points relating to the thermodynamics of nucleation and crystal growth. The resulting anatase TiO2 nanosheet films showed a specific superhydrophilicity without the need for any prior UV irradiation.