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1.
TiO 2 nanorod arrays (TiO 2 NRAs) sensitized with CdS nanoparticles were fabricated via successive ion layer adsorption and reaction (SILAR), and TiO 2 NRAs were obtained by oxidizing Ti NRAs obtained through oblique angle deposition. The TiO 2 NRAs decorated with CdS nanoparticles exhibited excellent photoelectrochemical and photocatalytic properties under visible light, and the one decorated with 20 SILAR cycles CdS nanoparticles shows the best performance. This can be attributed to the enhanced separation of electrons and holes by forming heterojunctions of CdS nanoparticles and TiO 2 NRAs. This provides a promising way to fabricate the material for solar energy conversion and wastewater degradation. 相似文献
2.
CdS and CdSe quantum dots were introduced as co-sensitizers into TiO 2 inverse opal quantum dot sensitized solar cells. Herein, the three-dimensionally ordered porous TiO 2 inverse opal film leads to a better infiltration of both sensitizers and hole transporting material, and the smaller surface area of TiO 2 inverse opal film is effectively offset by the incorporating of co-sensitization. It was found that the presence of CdS/CdSe co-sensitizers provides enhanced light absorption, and leads to a lower recombination rate of the electrons due to the stepwise structure of band edge in TiO 2/CdS/CdSe, which resulted in the observed enhanced photocurrent and energy conversion efficiency of the solar cells. A cell efficiency of 1.01 % has been attained. 相似文献
3.
In the present investigation, TiO 2, CdS and TiO 2/CdS bilayer system have been deposited on the fluorine doped tin oxide (FTO) coated glass substrate by chemical methods. Nanograined TiO 2 was deposited on FTO coated glass substrates by successive ionic layers adsorption and reaction (SILAR) method. Chemical bath deposition (CBD) method was employed to deposit CdS thin film on pre-deposited TiO 2 film. A further study has been made for structural, surface morphological, optical and photoelectrochemical (PEC) properties of FTO/TiO 2, FTO/CdS and FTO/TiO 2/CdS bilayers system. PEC behaviour of FTO/TiO 2/CdS bilayers was studied and compared with FTO/CdS single system. FTO/TiO 2/CdS bilayers system showed improved performance of PEC properties over individual FTO/CdS thin films. 相似文献
4.
A novel double-sided CdS quantum dots-sensitized TiO 2 nanotube (TNT)/ITO photoelectrode is fabricated to improve the energy conversion efficiencies of quantum dots-sensitized solar cells (QDSCs). Our experimental results show that the double-sided CdS quantum dots-sensitized TNT/ITO photoelectrodes show enhanced light absorption. As a consequence, the photoelectrochemical response of the CdS/TNT/ITO photoelectrode is much improved compared with single-sided CdS sensitized TNT arrays on Ti substrate (i.e., CdS/TNT/Ti photoelectrode). An optimum conversion efficiency of 7.5 % is achieved by the double-sided CdS(15)/TNT/ITO photoelectrode, which is an enhancement of about 120 % when compared with the single-sided CdS/TNT/Ti photoelectrode. Our results demonstrate that the energy conversion efficiencies of QDSCs can be improved by designing a new photoelectrode structure. 相似文献
5.
A quantum dot sensitized solar cell (QDSSC) is fabricated using hydrothermally grown TiO 2 nanorods and successive ionic layer adsorption and reaction (SILAR) deposited CdS. Surface morphology of the TiO 2 films coated with different SILAR cycles of CdS is examined by Scanning Electron Microscopy which revealed aggregated CdS QDs coverage grow on increasing onto the TiO 2 nanorods with respect to cycle number. Under AM 1.5G illumination, we found the TiO 2/CdS QDSSC photoelectrode shows a power conversion efficiency of 1.75%, in an aqueous polysulfide electrolyte with short-circuit photocurrent density of 4.04 mA/cm 2 which is higher than that of a bare TiO 2 nanorods array. 相似文献
6.
CdS quantum dot sensitized Gd-doped TiO 2 nanocrystalline thin films have been prepared by chemical method. X-ray diffraction analysis reveals that TiO 2 and Gd-doped TiO 2 nanocrystalline thin films are of anatase phase. The absorption spectra revealed that the absorption edge of CdS quantum dot sensitized Gd-doped TiO 2 thin films shifted towards longer wavelength side (red shift) when compared to that of CdS quantum dot sensitized TiO 2 films. CdS quantum dots with a size of 5 nm have been deposited onto Gd-doped TiO 2 film surface by successive ionic layer adsorption and reaction method and the assembly of CdS quantum dot with Gd-doped TiO 2 has been used as photo-electrode in quantum dot sensitized solar cells. CdS quantum dot sensitized Gd-doped TiO 2 based solar cell exhibited a power conversion efficiency of 1.18 %, which is higher than that of CdS quantum dot sensitized TiO 2 (0.91 %). 相似文献
7.
In this study, TiO 2 nanorods/CdS nanorods composite samples were successfully synthesized by grafting CdS nanorods on vertically aligned TiO 2 nanorods. A two-step hydrothermal method was used to prepare the samples. Some properties of the samples, such as morphological, structural, and optical properties were characterized by energy-dispersive X-ray detection, field emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and ultraviolet-visible spectroscopy. Moreover, photoelectrochemical properties were studied via current-voltage and photocurrent spectrum measurements. The results showed that CdS nanorods grafted on top of TiO 2 nanorods like a lawn. The amount grafted as well as the diameter and crystallinity of CdS nanorods increased first and then decreased as the grafting time increased, due to Ostwald ripening. Under the back-side illumination, the composite film with 2 h grafting time exhibited the highest photocurrent density which was almost twice of that of the pure TiO 2 nanorods. 相似文献
8.
Free-standing TiO 2 nanotube (NT) arrays have been prepared by a two-step anodization method. These translucent TiO 2 NT arrays can be transferred to the fluorine-doped tin oxide glass substrates to form front-side illuminated TiO 2 NT electrodes. The TiO 2 NT electrodes were double-sensitized by CdSe/CdS quantum dots (QDs) through successive ionic layer adsorption and reaction (SILAR) process. The absorption range of the TiO 2 NT electrode was extended from ~380 to 700 nm after sensitization with CdSe/CdS QDs. The SILAR cycles were investigated to find out the best combination of CdS and CdSe QDs for photovoltaic performance. The power conversion efficiency of 2.42 % was achieved by the CdSe(10)/CdS(8)/TiO 2 NT solar cell. A further improved efficiency of 2.57 % was obtained with two cycles of ZnS overlayer on the CdSe(10)/CdS(8)/TiO 2 NT electrode, which is 45.19 % higher than that of back-side illuminated solar cell. Furthermore, the ZnS(2)/CdSe(10)/CdS(8)/TiO 2 NT solar cell possesses a higher stability than CdSe(10)/CdS(8)/TiO 2 NT solar cell during the same period. The better photovoltaic performance of the ZnS(2)/CdSe(10)/CdS(8)/TiO 2 NT solar cell has demonstrated the promising value to design quantum dots-sensitized solar cells with double-sensitized front-side illuminated TiO 2 NT arrays strategy. 相似文献
9.
The CdS/TiO 2NTs composite was prepared by a simple two-step chemical solution routes to directly transfer trititanate nanotubes to TiO 2NTs and simultaneously coupled with CdS nanoparticles. The results of XRD, TEM, Diffuse reflectance UV-Visible absorption spectra revealed that the CdS nanoparticles were homogeneously embedded on the surface of TiO 2NTs and the absorption spectrum of TiO 2NTs was extended to visible region. The activity of hydrogen production by photocatalytic water decomposition for the CdS/TiO 2NTs composite was examined under visible light irradiation ( λ > 400 nm) and the quantity of H 2 evolution was ca. 1708 μL/g for 6 h. 相似文献
10.
TiO 2 nanowires prepared by thermal annealing of anodized Ti foil were sensitized with CdS quantum dots (QDs) via chemical bath deposition (CBD). Microstructural characterizations by SEM, TEM and XRD show that the CdS nanocrystals with the cubic structure have intimate contact to the TiO 2 nanowires. The amount of CdS QDs can be controlled by varying the CBD cycles. The experiment results demonstrate that the surface photovoltage (SPV) response intensity was significantly enhanced and the surface photovoltage response region was also expanded obviously for the TiO 2 NWs sensitized by CdS QDs. 相似文献
11.
TiO 2 nanoparticles with mean diameter of about 20 nm, average crystallite size of 15 nm and BET specific surface area of 78.88 m 2/g, were prepared through a simple sonochemical method and initial treatment in 10 M NaOH aqueous solution. XRD results exhibited that the obtained nanoparticles composed of pure rutile phase. During the initial treatment with NaOH aqueous solution, the Ti–O–Ti bonds in the TiO 6 octahedra structure of the raw material were broken, and new octahedras formed after ultrasonic irradiation. It is supposed that edge sharing was favored during ultrasonic treatment, leading to formation of the rutile nanoparticles. 相似文献
12.
Combustion reaction in the TiO 2-Al-C system was investigated by the combustion wave freezing technique with a wedge-shaped copper-made quenching block. The combustion reaction was a combined process in which the aluminothermic reduction of TiO 2 (3TiO 2 + 4Al 2Al 2O 3 + 3Ti) and TiC formation reaction (Ti + C TiC) occur in series. First, the aluminothermic reduction was activated by wet spreading of molten Al into interspaces between TiO 2 particles to produce rounded Al 2O 3 grains embedded in the Ti-rich liquid phase. In the later combustion stage, the Ti-rich phase reacted with the reactant C to produce TiC grains in the Ti-rich liquid phase. The three-dimensionally interconnected Al 2O 3 structure typically shown in this system mainly originated from interconnection between the rounded Al 2O 3 grains due to the high combustion temperature from the high exothermic TiC formation reaction. With decreasing the combustion temperature and controlling the C and TiC content, the interconnected Al 2O 3 structure changed to isolated. The isolated Al 2O 3 structure showed superior isothermal compaction behavior to the interconnected. Finally, it is suggested that the microstructure of combustion reaction should be one of the important factors in the SHS compaction process. 相似文献
13.
This report aimed to study the effect of CdS doping in TiO 2 on the phase transformation of TiO 2 from anatase to rutile using X-ray diffraction (XRD) and Raman spectroscopy. CdS-doped TiO 2 nanocomposites have been prepared and characterized using Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). We have observed that contrary to bare TiO 2, phase transformation of TiO 2 from anatase to rutile is hindered when doped with CdS at high temperature. Raman spectroscopy is found to be more sensitive for detection of the surface of TiO 2 as compared to XRD. 相似文献
14.
TiO 2 nanofibers decorated with Pt and Pd nanoparticles have been synthesized and studied in various photocatalytic processes. Excellent photocatalytic behavior in the decomposition of organic dyes in water, degradation of organic stains on the surface of flexible freestanding cellulose/catalyst composite films and in generation of hydrogen from ethanol using both suspended and immobilized catalysts are demonstrated. The performance of the nanofiber-based TiO 2 materials is competitive with??and in some cases outperforms??their conventional nanoparticle-based counterparts. In all cases, Pd-decorated TiO 2 nanoparticles and nanofibers proved to be more efficient than their Pt-based counterparts, which could be explained on the basis of the formation of nano-sized Schottky interfaces at the contacts between TiO 2 and metal nanoparticles. The feasibility of forming cellulose/catalyst composites provides a novel way of utilizing photocatalyst materials in large-area coatings and freestanding films. 相似文献
15.
Solid state reactions in the ZrO 2-Y 2O 3-TiO 2system have been studied and the solid solubility limit of TiO 2 in yttria stabilized tetragonal zirconia Y-TZP has been stablished. Structural characterization was carried out by XRD studies, and the changes in local structures with increasing TiO 2 in yttria stabilized tetragonal zirconia was analyzed for the first time by EXAFS and XANES measurements. The XANES results indicate a displacement of Ti ions from the center of symmetry with increasing titania content leading to assume a non randomly substitution of Ti
on Zr
sites in the tetragonal zirconia lattice. From the Ti-O and Ti-Ti measured distances, it has been assumed that the found electrical conductivity decrease with increasing titania content was due to both a trapping of the oxygen ion vacancies at Ti ions (Ti Zr Vö) and the formation of more complex associations like (Ti Zr Vö Ti Zr Vö), which giving rise to a reduction in the global concentration of moving oxygen vacancies. 相似文献
16.
In this work, two multilayer photoanode structures of TiO2/PbS(X)/CdS/ZnS/SiO2 and TiO2/PbS(X)/CdS/CdSe/ZnS/SiO2 were fabricated and applied in quantum dot-sensitized solar cells (QDSCs). Then, the effect of PbS QDs layer on the photovoltaic performance of corresponding cells was investigated. The sensitization was carried out by PbS and CdS QDs layers deposited on TiO2 scaffold through successive ionic layer adsorption and reaction (SILAR) method. The CdSe QDs film was also formed by a fast, modified chemical bath deposition (CBD) approach. Two passivating ZnS and SiO2 layers were finally deposited by SILAR and CBD methods, respectively. It was shown that the reference cell with TiO2/CdS/ZnS/SiO2 photoanode demonstrated a power conversion efficiency (PCE) of 3.0%. This efficiency was increased to 4.0% for the QDSC with TiO2/PbS(2)/CdS/ZnS/SiO2 photoelectrode. This was due to the co-absorption of incident light by low-bandgap PbS nanocrystalline film and also the CdS QDs layer and well transport of the charge carriers. For the CdSe included QDSCs, the PbS-free reference cell represented a PCE of 4.1%. This efficiency was improved to 5.1% for the optimized cell with TiO2/PbS(2)/CdS/CdSe/ZnS/SiO2 photoelectrode. The maximized efficiency was enhanced about 25% and 70% compared to the PbS-free reference cells with and without the CdSe QDs layer. 相似文献
17.
Inspired by nature, artificial photosynthesis through the construction of direct Z‐scheme photocatalysts is extensively studied for sustainable solar fuel production due to the effectiveness in enhancing photoconversion efficiency. However, there is still a lack of thorough understanding and direct evidence for the direct Z‐scheme charge transfer in these photocatalysts. Herein, a recyclable direct Z‐scheme composite film composed of titanium dioxide and cadmium sulfide (TiO 2/CdS) is prepared for high‐efficiency photocatalytic carbon dioxide (CO 2) reduction. In situ irradiated X‐ray photoelectron spectroscopy (ISI‐XPS) confirms the direct Z‐scheme charge‐carrier migration pathway in the photocatalytic system. Furthermore, density functional theory simulation identifies the intrinsic cause for the formation of the direct Z‐scheme heterojunction between the TiO 2 and the CdS. Thanks to the significantly enhanced redox abilities of the charge carriers in the direct Z‐scheme system, the photocatalytic CO 2 reduction performance of the optimized TiO 2/CdS is 3.5, 5.4, and 6.3 times higher than that of CdS, TiO 2, and commercial TiO 2 (P25), respectively, in terms of methane production. This work is a valuable guideline in preparation of highly efficient recyclable nanocomposite for photoconversion applications. 相似文献
18.
Mesoporous Au/TiO 2 nanocomposites with different Au particle size (7.3–11.8 nm) were synthesized via deposition–precipitation method. The synthesized nanocomposites have been characterized by XRD, TEM, XPS, DLS, ICP-OES, N 2 sorpometry, and UV–Vis spectroscopy. Au/TiO 2 showed higher quantum yield and greater photocatalytic efficiency compared to pure TiO 2 under both ultraviolet and sunlight illumination. The increase of the photocatalytic efficiency of TiO 2 upon deposition with gold nanoparticles, Au NPs, is due to the interface electron transfer from Au nanoparticles to TiO 2 under visible light illumination and from TiO 2 to Au nanoparticles under UV illumination. For the first time, the effect of Au particle sizes when it is very similar to the interparticles pores of TiO 2 has been investigated. The highest reaction rate (5.7 × 10 ?2 min ?1) and degradation efficiency of Safranin-O (SO) dye (97 %) were observed when the deposited gold nanoparticles are the smallest among the studied samples ( sAu/TiO 2). In spite of blocking a high percentage of the TiO 2 pores, the sAu/TiO 2 sample demonstrated a complete degradation of SO dye in 50 min which is more efficient than any other reported catalysts in the literature. 相似文献
19.
In this report, a novel and facile in situ gas–solid reaction method has been developed for the deposition of CdS quantum-dots (QDs) on a mesoscopic TiO 2 film. In the approach, cadmium nitrate solution was first coated on mesoporous TiO 2 films, and subsequently transformed into CdS QDs (with size about 2–3 nm) by reaction with hydrogen sulfide (H 2S) gas generated in a closed container at room temperature. Different from the conventional solution techniques, this method offers new opportunities for rapid and facile deposition of CdS QD-coated TiO 2 films without the introduction of the by-products. With the CdS QDs-decorated TiO 2 active electrodes, the liquid and solid solar cells were fabricated with power conversion efficiencies ( PCEs) of 1.90 and 0.80%, respectively. 相似文献
20.
The photoelectrochemical properties of TiO 2, CdS, and TiO 2/CdS anodes have been studied. The results demonstrate that, under illumination, CdS anodes are subject to photocorrosion,
and Cd 2+ ions pass into solution. Corrosion-resistant films of TiO 2 prevent CdS photocorrosion, and the CdS/TiO 2 system exhibits good photosensitivity in the visible range. 相似文献
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