Zuoli He

Photocatalytic Degradation of Methyl Orange over Nitrogen–Fluorine Codoped TiO2 Nanobelts Prepared by Solvothermal Synthesis

Anatase type nitrogen-fluorine (N-F) codoped TiO(2) nanobelts were prepared by a solvothermal method in which amorphous titania microspheres were used as the precursors. The as-prepared TiO(2) nanobelts are composed of thin narrow nanobelts and it is noted that there are large amount of wormhole-like mesopores on these narrow nanobelts. Photocatalytic activity of the N-F codoped TiO(2) nanobelts was measured by the reaction of photocatalytic degradation of methyl orange. Results indicate that the photocatalytic activity of the N-F codoped TiO(2) nanobelts is higher than that of P25, which is mainly ascribed to wormhole-like mesopores like prison, larger surface area, and enhanced absorption of light due to N-F codoping. Interestingly, it is also found that the photocatalytic activity can be further enhanced when tested in a new testing method because more photons can be captured by the nanobelts to stimulate the formation of the hole-electron pair.

Double-Layer Electrode Based on TiO2 Nanotubes Arrays for Enhancing Photovoltaic Properties in Dye-Sensitized Solar Cells

The present work reports a rapid and facile method to fabricate a novel double-layer TiO2 photoanode, which is based on highly ordered TiO2 nanotube arrays and monodispersive scattering microspheres. This double-layer TiO2 sphere/TNTA photoanode have got many unique structural and optical properties from TiO2 scattering microspheres, such as high specific surface area, multiple interparticle scattering, and efficient light-harvesting. Results indicate that this as-fabricated double-layer TiO2 sphere/TNTA front-illumination dye-sensitized solar cell, which is fabricated from the TiO2 nanotube arrays with a 17.4 μm length after TiCl4 treatment, exhibits a pronounced power conversion efficiency of 7.24% under an AM1.5 G irradiation, which can be attributed to the increased incident photon-to-current conversion and light-harvesting efficiency.

Nanosphere assembled mesoporous titanium dioxide with advanced photocatalystic activity using absorbent cotton as template

Nanosphere assembled mesoporous TiO2 products with large specific surface area and high crystallinity were prepared by a combined hydrothermal and post-heating process, where absorbent cotton was used as a template. The as-synthesized samples were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption/desorption, Fourier transform infrared spectroscopy, and UV–Vis diffuse reflectance spectroscopy. Results indicate that the obtained products exhibit a unique 3D mesoporous structure and demonstrate a significantly improved photocatalytic performance, which can be attributed to concurrent effects of high surface area, the presence of accessible mesopores channels and high crystallinity.

Bi2Sn2O7–TiO2 nanocomposites for enhancing visible light photocatalytic activity

Bi2Sn2O7–TiO2 nanocomposites with different ratios of Bi2Sn2O7 (BSO) and TiO2 were prepared by combining a facile co-precipitation method with the aid of a template. X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy were employed to characterize the physicochemical properties of the as-prepared nanocomposites. The band gap energies of the nanocomposites were established by diffuse reflectance UV-Vis spectra. The specific surface area and average pore diameter of the nanoparticles were measured by an N2 adsorption–desorption isotherm. Photocatalytic degradation of Rhodamine B dye molecules was also investigated in the visible region so as to explore the photocatalytic activity of the as-prepared nanocomposites. The results showed that the 10BSO–TiO2 nanocomposites had a remarkably enhanced photocatalytic performance as compared with other samples including anatase TiO2. It was also found that all BSO modified TiO2 samples had a wider band gap energy than the pure BSO sample, but showed a higher photocatalytic activity than the pure BSO sample due to the photosensitization mechanism of the dye molecules.

Photoreversible [2] Catenane via the Host-Guest Interactions between a Palladium Metallacycle and β-Cyclodextrin

We report the efficient preparation of an A2D2 (A = acceptor and D = donor) metallacycle 2 = [(en)2Pd2(1)2](NO3)4, using the coordination driven self-assembly of trans-azobenzene based bispyridyl ligand 1 and (en)Pd(NO3)2 (en = ethylenediamine). In the metallacycle, the trans-azobenzene units serve both as a structural element and as sites for subsequent host-guest chemistry with β-cyclodextrin, leading to the formation of a [2] catenane 3. This catenation process is reversible and can be switched off and on in a photocontrollable manner via the trans-cis isomerization of the azobenzene units.

Enhanced Conversion Efficiencies in Dye-Sensitized Solar Cells Achieved through Self-Assembled Platinum(II) Metallacages.

Two-component self-assembly supramolecular coordination complexes with particular photo-physical property, wherein unique donors are combined with a single metal acceptor, can be utilized for many applications including in photo-devices. In this communication, we described the synthesis and characterization of two-component self-assembly supramolecular coordination complexes (SCCs) bearing triazine and porphyrin faces with promising light-harvesting properties. These complexes were obtained from the self-assembly of a 90° Pt(II) acceptor with 2,4,6-tris(4-pyridyl)-1,3,5-triazine (TPyT) or 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine (TPyP). The greatly improved conversion efficiencies of the dye-sensitized TiO2 solar cells were 6.79 and 6.08 respectively, while these SCCs were introduced into the TiO2 nanoparticle film photoanodes. In addition, the open circuit voltage (Voc) of dye-sensitized solar cells was also increased to 0.769 and 0.768 V, which could be ascribed to the inhibited interfacial charge recombination due to the addition of SCCs.

Hydrogen titanium oxide hydrate: excellent performance on degradation of methyl blue in aqueous solutions

Nanotube-assembled flower-like hydrogen titanium oxide hydrate (H2Ti2O4(OH)2), which has degradation capacity for methyl blue (MB) even in darkness, was prepared via a microwave solvothermal process. Physicochemical features of the hydrogen titanium oxide hydrate powders were characterized by X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, Fourier transform-infrared spectroscopy and UV/VIS/NIR spectrometry. The degradation of methyl blue (MB), methyl orange (MO) and Rhodamine B (Rhb) solution with a water-cooling system was carried out to study the photocatalytic properties of the powders. Results indicate that the H2Ti2O4(OH)2 has excellent performance on degradation of MB, which can be attributed to the hydroxyl group (–OH) from the surface of the catalysts confirmed by electron spin resonance signals (ESR). Furthermore, the intensity of ESR signals rapidly increased with the irradiation time and did not reach maximum after 11 min, which indicated that the photogenerated holes in the valence band of H2Ti2O4(OH)2 catalysts reacted rapidly with surface-bound water or the hydroxyl group and produced a large amount of ˙OH, which was beneficial for degrading MB. The degradation results indicate that these catalysts have potential uses in removing harmful carcinogens from water, in addition to possible applications in reducing the harmful effects of oil spills.