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A novel cheap, one-step and facile synthesis of hierarchical TiO2 nanotubes as fast electron transport channels for highly efficient dye-sensitized solar cells
摘要： The well-aligned hierarchical TiO2 nanotubes (HTNTs) have been synthesized by a one-step hydrothermal method employing potassium titanium oxalate, ethanol and H2O, which are strongly adhered onto transparent conducting oxide glass. The preparation is straightforward, cheap and applicative for mass manufacture. The thickness of membranes is changed from 12 to 22 lm by adjusting the reaction time. The HTNTs consist of one-dimensional (1D) long TiO2 nanotube trunks and numerous short TiO2 nanorod branches, which can balance surface area and charge transport. By employing optimized HTNTs for dye-sensitized solar cells, a remarkable power conversion ef?ciency of 9.89% is obtained. The result is superior to P25 (8.34%), because 1D trunk-1D branch structure of HTNTs offers the advantages of strong light-harvesting, directed electron transport, and ef?cient charge collection. The HTNTs may ?nd an underlying application in the manufacture of photovoltaic devices.
关键词： Dye-sensitized solar cell,Titania,Hierarchical structure,Charge transport,Nanotube
更新于2025-09-19 17:13:59
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The optimization of surface morphology of Au nanoparticles on WO3 nanoflakes for plasmonic photoanode
摘要： Among many candidates for photoanode materials of photoelectrochemical (PEC) cell, nanostructured tungsten trioxide (WO3) is regarded as one of the most promising materials due to its superior electrical properties and adequate bandgap (~2.8eV) and band edge position. WO3 nanoflakes(WO3 NFs), which have merits on its high surface area and crystallinity, have been actively studied for this manner but solar-to-hydrogen (STH) efficiency of WO3 NFs based photoanode is still not sufficient both in light absorption and charge separation. Plasmon-induced enhancement using Au nanoparticles is excellent approach for both the efficiency of light absorption and charge separation of WO3. However, it still needs optimization on its amount, shape, coverage, and e.t.c. Here, we synthesized WO3 NFs by solvothermal growth and decorated gold nanoparticles on these nanoflakes by e-beam evaporation and rapid thermal annealing (RTA) process in a row. By this process, a large-area AuNPs/WO3 nanocomposite structure with various size, interparticle distance, and coverage of AuNPs were fabricated. These AuNPs/WO3 NFs type photoanode achieve high light absorption both in UV and visible range and consequently higher photocurrent density. The optimized AuNPs/WO3 nanocomposite photoanode exhibits 1.01mA/cm2 of photocurrent density, which is increased to 19.8% compared with bare WO3 nanoflakes. Field emission-scanning electron microscope(FE-SEM), X-ray Diffraction(XRD), UV-vis spectrometer analysis were measured to analyze the morphology and crystallinity and relationship between structure and PEC performance.
关键词： Au nanoparticles,WO3 nanoflakes,plasmonic photoanode,Au/WO3 hierarchical structure,LSPR
更新于2025-09-19 17:13:59
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Electrochemical Fabrication of rGO-embedded Ag-TiO2 Nanoring/Nanotube Arrays for Plasmonic Solar Water Splitting
摘要： Effective utilization of hot electrons generated from the decay of surface plasmon resonance in metal nanoparticles is conductive to improve solar water splitting efficiency. Herein, Ag nanoparticles and reduced graphene oxide (rGO) co-decorated hierarchical TiO2 nanoring/nanotube arrays (TiO2 R/T) were facilely fabricated by using two-step electrochemical anodization, electrodeposition, and photoreduction methods. Comparative studies were conducted to elucidate the effects of rGO and Ag on the morphology, photoresponse, charge transfer, and photoelectric properties of TiO2. Firstly, scanning electron microscope images confirm that the Ag nanoparticles adhered on TiO2 R/T and TiO2 R/T-rGO have similar diameter of 20 nm except for TiO2 R-rGO/T. Then, the UV–Vis DRS and scatter spectra reveal that the optical property of the Ag-TiO2 R/T-rGO ternary composite is enhanced, ascribing to the visible light absorption of plasmonic Ag nanoparticles and the weakening effect of rGO on light scattering. Meanwhile, intensity-modulated photocurrent spectroscopy and photoluminescence spectra demonstrate that rGO can promote the hot electrons transfer from Ag nanoparticles to Ti substrate, reducing the photogenerated electron–hole recombination. Finally, Ag-TiO2 R/T-rGO photoanode exhibits high photocurrent density (0.98 mA cm?2) and photovoltage (0.90 V), and the stable H2 evolution rate of 413 μL h?1 cm?2 within 1.5 h under AM 1.5 which exceeds by 1.30 times than that of pristine TiO2 R/T. In line with the above results, this work provides a reliable route synergizing rGO with plasmonic metal nanoparticles for photocatalysis, in which, rGO presents a broad absorption spectrum and effective photogenerated electrons transfer.
关键词： TiO2 nanoring/nanotube hierarchical structure,Spectral responses,Plasmonic Ag nanoparticles,Reduced graphene oxide,Water splitting
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE Eurasia Conference on IOT, Communication and Engineering (ECICE) - Yunlin, Taiwan (2019.10.3-2019.10.6)] 2019 IEEE Eurasia Conference on IOT, Communication and Engineering (ECICE) - Amount and Scattering of Dyes and their Influence on the Photocurrent Enhancement of TiO2 Hierarchically Structured Photoanodes for Dye-Sensitized Solar Cells
摘要： In this study, we prepared and analyzed the properties of hills-like hierarchically structured TiO2 photoanodes for dye-sensitized solar cells (DSSCs). We expected that the presence of appropriately aggregated TiO2 clusters in the photoanode layer would translate in a relatively strong light scattering and dye loading, increasing the photovoltaic efficiency. A detailed light-harvesting study was performed by employing polyvinyl alcohol (PVA) polymers of different molecular weights as binders for the aggregation of the TiO2 nanoparticles (P-25 Degussa). Hence, we obtained a series of TiO2 films presenting a variety of morphologies. Their reflection, as well as the absorbance of the attached dye, the amount of dye loading, and the performance of the fabricated DSSC devices were investigated. Our optimized device presenting a relatively high dye loading and well light harvesting ability, and able to enhance the short-circuit current (Jsc) in the DSSCs by 23%.
关键词： Dye-sensitized solar cell,Hierarchical structure,Light scattering,TiO2 photoanode
更新于2025-09-16 10:30:52
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Dyes Amount and Light Scattering Influence on the Photocurrent Enhancement of Titanium Dioxide Hierarchically Structured Photoanodes for Dye-Sensitized Solar Cells
摘要： In this study, we prepared and analyzed the properties of hill-like hierarchically structured titanium dioxide (TiO2) photoanodes for dye-sensitized solar cells (DSSCs). We expected that the presence of appropriately aggregated TiO2 clusters in the photoanode layer would translate to relatively strong light scattering and dye loading, increasing the photovoltaic efficiency. A detailed light-harvesting study was performed by employing polyvinyl alcohol (PVA) polymers of different molecular weights as binders for the aggregation of the TiO2 nanoparticles (P-25 Degussa). Hence, we obtained a series of TiO2 films, presenting a variety of morphologies. Their reflection, as well as absorbance of light by the attached dye, the amount of dye loading, and the performance of the fabricated DSSC devices were investigated. Our optimized device, with a relatively high dye loading and good light harvesting ability, was able to enhance the short-circuit current (Jsc) in the DSSCs by 23%.
关键词： hierarchical structure,TiO2 photoanode,light scattering,dye-sensitized solar cell
更新于2025-09-16 10:30:52
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Architecturing CoTiO3 overlayer on nanosheets-assembled hierarchical TiO2 nanospheres as a highly active and robust catalyst for peroxymonosulfate activation and metronidazole degradation
摘要： Catalytic performance of a heterogeneous cobalt-based catalyst for advanced oxidative process (AOP) correlates tightly with its structure and composition. The main objective of this study is to maximize the utilization and accessibility of cobalt sites while enhancing their activity and stability through rational structural and composition designs, and thus to achieve an excellent performance for heterogeneous peroxymonosulfate (PMS) activation. To this end, a novel CoTiO3/TiO2 composite (CTT), composed of CoTiO3 overlayer on nanosheets-assembled hierarchical TiO2 nanospheres, was elaborately designed and synthesized. The resulting CTT possessed certain features including CoTiO3-rich surface, large surface area (114.8 m2 g?1), and highly open porous channels, which afforded sufficient accessible active sites against undesirable particle agglomeration and shedding. Moreover, cobalt sites of CTT exhibited a higher activity toward PMS than those of Co3O4 due to the composition-induced distinct adsorption nature, easy electron transfer, and strong bond-weakening ability. Benefitting from the unique combination of structural and compositional advantages, CTT manifested remarkable catalytic efficiency, low cobalt leaching (0.078 mg L?1), and excellent reusability in activation of PMS for degradation of the emerging antibiotic pollutant metronidazole (MNZ). The potential degradation pathway for MNZ and the catalytic mechanism were further elucidated. The design strategy proposed in this study may provide a new opportunity for future development of high-performance heterogeneous cobalt-based catalysts in remediation of aquatic environment.
关键词： Heterogeneous cobalt-based catalyst,CoTiO3-rich surface,Metronidazole,Peroxymonosulfate activation,Catalytic degradation,Nanosheets-assembled hierarchical structure
更新于2025-09-12 10:27:22
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Au/TiO2 nanotube array based multi-hierarchical architecture for highly efficient dye-sensitized solar cells
摘要： Control over balanced high light-harvesting and efficient charge transport is of crucial importance for photoelectrochemical applications but still remains great challenge. We develop here single-wall TiO2 nanotube array with in-situ deposited Au nanoparticles. Based on this Au–TiO2 hybrid, we further build a “cigar-like” Au/TiO2-nanotube-array/TiO2-nanoparticles multi-hierarchical architecture through a novel vacuum-assisted colloid-filling approach for dye-sensitized solar cell application. In this elaborate structure, Au nanoparticles welding on nanotube walls play dual roles of direct injecting hot electrons into TiO2 to elevate the conductivity of TiO2 film by about 4 times (under illumination) for fast electron transport, and introducing a plasmonic effect to improve light-harvesting as well. Meanwhile, the thick TiO2 nanoparticulate decoration provides the photoanode vast surface area for ~3.2 times the dye-loading amount of the pristine TiO2 nanotube array based electrode, which will further boost the light-harvesting remarkably. The resulting dye-sensitized solar cell yields an impressively high power conversion efficiency of 8.93%, which is 190.4% that of the pristine TiO2 nanotube array based device. The technology presented in this work provides also a promising prospect for the preparation of multi-hierarchical structures for a wide range of applications, such as photocatalysis and gas sensors.
关键词： Hot electron,Vacuum filling,Dye-sensitized solar cells,Hierarchical structure,Plasmon
更新于2025-09-12 10:27:22
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Ultrathin Co-Co LDHs nanosheets assembled vertically on MXene: 3D nanoarrays for boosted visible-light-driven CO2 reduction
摘要： Converting carbon dioxide (CO2) to multiple energy-rich chemicals by photocatalysis could validly mitigate the severe issues of climate changes and energy shortages. Exploring efficient catalysts for enhancing the performance of CO2 photoreduction is still challenging. Herein, a novel three-dimensional hierarchical Co-Co layered double hydroxide/Ti3C2TX nanosheets (Co-Co LDH/TNS) nanoarray was successfully prepared via an in-situ MOF-derived strategy. This wise design rationally integrates the functional and structural merits of active Co species with conductive MXene to a hierarchical nanoarray architecture composed of ultrathin nanosheets, which can remarkably promote separation of photogenerated charge carriers and accelerate electrons transmission. Benefitting from these features, the hierarchical Co-Co LDH/TNS composites manifest significant enhancement on the CO2-to-CO evolving rate (1.25×104 μmol h?1 g-1) under illumination (>400nm) with a high apparent quantum efficiency (0.92%) and excellent stability. Our work demonstrates that 3D hybrid structure composed of MXene species can serve as promising candidates for CO2 photoreduction, providing fundamental guidance to improve photocatalytic performance by rational engineering of complex hierarchical architecture materials.
关键词： hierarchical structure,electrons transfer,CO2 reduction,photocatalysis,Ti3C2TX nanosheets
更新于2025-09-11 14:15:04
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Constructing hierarchical SnO2 nanofiber/nanosheets for efficient formaldehyde detection
摘要： SnO2 nanofiber/nanosheets with hierarchical nanostructures were successfully synthesized via a facile hydrothermal method by using hollow SnO2 nanofibers as the backbone. The microstructure, morphology, chemical composition, oxidation states and surface areas of SnO2 nanofibers, SnO2 nanofiber/nanosheets and SnO2 nanosheets were comparatively studied by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET). The characterization results indicated that the hierarchical SnO2 nanofiber/nanosheets were constructed by nanosheets arrays uniform growth on the surface of nanofibers. Sensing performances of SnO2-based nanomaterials were investigated utilizing formaldehyde (HCHO) as a target gas. Compared to SnO2 nanofibers, nanosheets and the physical mixture of nanofibers and nanosheets, the gas sensor based on SnO2 nanofiber/nanosheets exhibited better response, more excellent selectivity, transient response and trace detection ability to HCHO gas. The response (Ra/Rg) of the gas sensor is 57 toward 100 ppm HCHO at 120 °C, which is about 300% and 200% higher than that of pure SnO2 nanofibers sensors and SnO2 nanosheets sensors, respectively. Furthermore, the sensor has an excellent response/recovery performance with 4.7 s and 11.6 s for detecting 100 ppm HCHO. Both the growth process and the gas sensing mechanism of SnO2 hierarchical nanostructures were discussed. Successful preparation of SnO2 nanofiber/nanosheets is attributed to uniform decoration of seeds on the nanofibers and suitable growth conditions of nanosheets. Enhanced sensing performance mainly result from the synergistic effect of nanofibers and nanosheets, hierarchical structures and larger specific surface areas. The synthetic strategy can also be applied in preparing hierarchical materials of different constituent materials.
关键词： Homogeneous materials,SnO2 nanofiber/nanosheets,Formaldehyde gas sensors,Hierarchical structure
更新于2025-09-10 09:29:36
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Synthesis of 3D Hierarchical Structure TiO2 and Its Photocatalytic Activity
摘要： 3D hierarchical structure TiO2 can be synthesized via a solvothermal method using butyl titanate as precursor and acetic acid as solvent. The microspheres were characterized and analyzed by X-ray diffraction (XRD), electron microscope scanning (SEM), transmission electron microscope (TEM), N2 adsorption-desorption, the ultraviolet, X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL), ultraviolet and visible spectrophotometer (UV-Vis). The photocatalytic degradation performance was evaluated under the condition of methyl orange (MO) simulating wastewater. The results showed that the 3D hierarchical structure was one-step synthesized by the coordination of several surfactants, and as the time of solvent heat increases, morphology, and structure can be regulated from a 3D hierarchical structure to the grain-shaped, and the process of dissolution, recrystallization and orientated growth occurred during the course of reaction, which is different from the previous literature. The morphology of TiO2 can be regulated and controlled by reaction time. 3D hierarchical structure anatase TiO2 exhibited excellent photocatalytic activity in the degradation of organic compounds. The unit of hierarchy structure interconnected with each other, forming of various sizes of holes, which increase the specific surface area and are beneficial to the diffusion of the object molecules.
关键词： Solvothermal,Photocatalysis,3D hierarchical structure,Titania
更新于2025-09-09 09:28:46