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TiO 2 nanotube arrays (TiO 2 NTAs) were firstly used as photoanode in methylammonium lead iodide (CH 3 NH 3 PbI 3 ) perovskite/TiO 2 NTAs heterojunction solar cell, where CH 3 NH 3 PbI 3 functions as both light absorber and hole conductor. The composition, structure and photoelectrochemical properties of the as-prepared samples were characterized by x-ray diffractometer (XRD), field-emission scanning electron microscope (FE-SEM), ultraviolet-visible (UV–vis) spectrophotometer and electrochemical workstation. The results indicate that the as-prepared CH 3 NH 3 PbI 3 belongs to the cubic crystal system, and TiO 2 NTAs sensitized by 0.3 M CH 3 NH 3 I and PbI 2 exhibit the best photoelectrochemical properties with an open-circuit voltage of 0.422 V and a short-circuit current density of 173.4 μA cm −2 . The EIS result shows that the extremely large resistance at CH 3 NH 3 PbI 3 /FTO interface contributes to the low current density of the perovskite solar cell. [ABSTRACT FROM AUTHOR]

A nearly 100% filling of PEDOT in TiO 2 nanotube array (NTA) was successfully prepared by a simple electropolymerization method at a constant potential of 1.8 V, which was demonstrated by field emission scanning electron microscopy (FESEM). UV–vis diffusion reflection spectroscopy (DRS) revealed that the filling of PEDOT in TiO 2 NTA can dramatically improve the visible-light and near-infra-red absorption property of the TiO 2 NTA, which is especially useful for the application of solar cells. Cyclic voltammetry experiments indicate that the PEDOT–TiO 2 NTA hybrid material is electrochemically more active than the TiO 2 NTA and has excellent redox reversibility. [ABSTRACT FROM AUTHOR]

Abstract: CdTe and ZnS quantum dots sensitized TiO2 nanotube array photoelectrodes were prepared by depositing CdTe and ZnS QDs on the tube walls of the self-organized TiO2 NTs using successive ionic layer adsorption and reaction (SILAR) technique. The deposition of CdTe and ZnS on the upper and inner surface of the TiO2 NTs was confirmed by field emission scanning electron (FE-SEM) and transmission electron microscopes (TEM). The obtained results indicated that TiO2 NTs photoelectrodes sensitized by CdTe quantum dots for 5 cycles exhibited excellent photoelectrochemical properties, with an open-circuit voltage of 0.95V and a short circuit current density of 11.15mAcm−2, and ZnS coating protected the photoelectrodes against photocorrosion. [Copyright &y& Elsevier]

Abstract: The Ag and CdS nanoparticles co-sensitization of TiO2 nanotubes (CdS–Ag/TiO2 NTs) were prepared by successive ionic layer adsorption and reaction (SILAR) technique. The phase composition, morphology and optical property were characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis diffusion reflection spectroscopy (DRS). The co-modification of Ag and CdS nanoparticles expanded the photoresponse range of TiO2 NTs from ultraviolet region to 668.7nm, and the CdS–Ag/TiO2 NTs prepared by SILAR deposition of 5 cycles exhibited higher visible photocurrent and stability against photocorrosion. The detailed electrons transfer mechanism of CdS–Ag/TiO2 NTs was proposed, and photocatalytic activity toward degradation of methyl orange (MO) under visible-light irradiation was also investigated. [Copyright &y& Elsevier]

Abstract: Ordered anatase TiO2 nanotubes (TiO2 NTs) on Ti substrate were synthesized by electrochemical anodization and subsequently vapor-thermal treatment. Ag nanoparticles were decorated on TiO2 NTs by successive ionic layer adsorption and reaction (SILAR) technique. Raman spectroscopy, X-ray absorption near edge spectroscopy (XANES), X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used for the characterization of surface morphology, phase composition, and microstructure of the original TiO2 NTs, the vapor-thermally treated TiO2 NTs and the Ag nanoparticles decorated TiO2 NTs. The results indicate that vapor-thermal treatment favors to the transformation of amorphous TiO2 into anatase phase. Increasing the SILAR cycle times favors to increase the loaded amounts of Ag nanoparticles in TiO2 NTs. Ag nanoparticles are uniformly distributed in the TiO2 NTs, and the SILAR process does not damage the ordered tubular structure. A possible formation mechanism of Ag/TiO2 NTs has also been proposed. The photocatalytic results showed that the Ag nanoparticle modified TiO2 NTs largely enhanced the photocatalytic degradation of methyl orange under ultraviolet light irradiation. [Copyright &y& Elsevier]

Abstract: Nitrogen-doped titanium dioxide mesosponge was fabricated by transformation of TiO2 nanotube arrays using a facial solvothermal method. The structure, morphology and optical property were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–vis diffusion reflection spectroscopy (DRS). A possible formation mechanism of N-doped TiO2 mesosponge has been proposed. The photoelectrochemical results indicate that N-doped TiO2 mesosponge prepared in ethanol solution of ammonia exhibits much higher photocurrent densities and the optimal photocatalytic activity. [Copyright &y& Elsevier]

The capacitance of MnO2 supercapacitors (SCs) is not high as expected due to its low conductivity of MnO2. The synergistic effects of MnO2 with high theoretical specific capacitance and TiN with high theoretical conductivity can extremely enhance the electrochemical performance of the MnO2-TiN electrode material. In this work, we synthesized different nanostructured and crystalline-structured MnO2 modified TiN nanotube arrays electrode materials by hydrothermal method and explained the formation mechanism of different nanostructured and crystalline-structured MnO2. The influences of MnO2 nanostructures and crystalline-structures on the electrochemical performance has been contrasted and discussed. The specific capacitance of δ-MnO2 nanosheets-TiN nanotube arrays can reach 689.88 F g−1, the highest value among these samples TN-MO-SS, TN-MO-S, TN-MO-SR, TN-MO-RS, and TN-MO-R. The reason is explained based on MnO2 nanostructure and crystalline-structure and electron/ion transport properties. The specific capacitance retention rates are 97.2% and 82.4% of initial capacitance after 100 and 500 cycles, respectively, indicating an excellent charging-discharging cycle stability. [ABSTRACT FROM AUTHOR]