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Reduced Graphene Oxide–TiO2 Nanotube Composite: Comprehensive Study for Gas Sensing Applications
摘要： Graphene oxide (GO) and reduced graphene oxide (RGO) have unique properties that can revolutionize performances of functional devices. Graphene-based materials can be coupled with metal oxide nanomaterials for gas sensing applications. In this work, we report the synthesis and the gas sensing properties of a composite material based on RGO loaded TiO2 nanotubes. To properly tune the reduction of GO to RGO we adopted a gas-phase process that can be applied in situ on each gas sensor device, allowing to track the process effects through the sensor conductance. We systematically investigated the gas-response dependence from RGO loading and its reduction, showing the occurrence of an optimal RGO concentration arising from the interplay of these two parameters. Hence, these two factors should be considered in parallel to functionalize the metal oxide materials with GO for the fabrication of chemical sensor devices.
关键词： TiO2 nanotube,gas sensing,reduced graphene oxide,reduction effect,surface functionalization,Graphene oxide
更新于2025-09-09 09:28:46
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AIP Conference Proceedings [Author(s) PROCEEDINGS OF THE 3RD INTERNATIONAL SYMPOSIUM ON CURRENT PROGRESS IN MATHEMATICS AND SCIENCES 2017 (ISCPMS2017) - Bali, Indonesia (26–27 July 2017)] - The newest material Fe3O4/TiO2/CuO/NGP composites for removal of methylene blue dye by adsorption and photocatalysis
摘要： In this research, FCT nanocomposites were synthesized using a sol-gel method and Fe3O4/CuO/TiO2 (FCT)/NGP composites were synthesized using a co-precipitation method. All prepared samples were characterized by X-ray diffraction (XRD), Fourier energy dispersive X-ray (EDX) spectroscopy, vibrating sample magnetometry (VSM), and thermogravimetric analysis (TGA). Methylene blue was used as a model for organic dyes to determine the adsorptive properties of all prepared samples. The removal of methylene blue from aqueous solution was investigated using an adsorption process. All samples followed a pseudo second order kinetic reaction. The maximum adsorption capacity was 48 mg/g.
关键词： Fe3O4,TiO2,adsorption,photocatalytic,graphene
更新于2025-09-09 09:28:46
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ALMA observations of TiO <sub/>2</sub> around VY CMa
摘要： Titanium dioxide, TiO2, is a refractory species that could play a crucial role in the dust-condensation sequence around oxygen-rich evolved stars. We present and discuss the detections of 15 emission lines of TiO2 with ALMA in the complex environment of the red supergiant VY CMa. The observations reveal a highly clumpy, anisotropic out?ow in which the TiO2 emission likely traces gas exposed to the stellar radiation ?eld. We ?nd evidence for a roughly east-west oriented, accelerating bipolar-like structure, of which the blue component runs into and breaks up around a solid continuum component. We see a distinct tail to the south-west for some transitions, consistent with features seen in the optical and near-infrared. We ?nd that a signi?cant fraction of TiO2 remains in the gas phase outside the dust-formation zone and suggest that this species might play only a minor role in the dust-condensation process around extreme oxygen-rich evolved stars like VY CMa.
关键词： oxygen-rich evolved stars,ALMA,dust-condensation,TiO2,VY CMa
更新于2025-09-09 09:28:46
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Impact of Overlapping Fe/TiO <sub/>2</sub> Prepared by Sol-Gel and Dip-Coating Process on CO <sub/>2</sub> Reduction
摘要： Fe-doped TiO2 (Fe/TiO2) film photocatalyst was prepared by sol-gel and dip-coating process to extend its photoresponsivity to the visible spectrum. To promote the CO2 reduction performance with the photocatalyst, some types of base materials used for coating Fe/TiO2, which were netlike glass fiber and Cu disc, were investigated. The characterization of prepared Fe/TiO2 film coated on netlike glass fiber and Cu disc was analyzed by SEM and EPMA. In addition, the CO2 reduction performance of Fe/TiO2 film coated on netlike glass disc, Cu disc, and their overlap was tested under a Xe lamp with or without ultraviolet (UV) light, respectively. The results show that the concentration of produced CO increases by Fe doping irrespective of base material used under the illumination condition with UV light as well as that without UV light. Since the electron transfer between two overlapped photocatalysts is promoted, the peak concentration of CO for the Fe/TiO2 double overlapping is approximately 1.5 times as large as the Fe/TiO2 single overlapping under the illumination condition with UV light, while the promotion ratio is approximately 1.1 times under that without UV light.
关键词： UV light,Fe-doped TiO2,visible spectrum,photocatalyst,dip-coating,sol-gel,CO2 reduction
更新于2025-09-09 09:28:46
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Photocatalytic Degradation Mechanism of Reactive Brilliant Blue X-BR by Expanded Perlite/TiO2
摘要： Expanded perlite loaded titanium dioxide photocatalysts were prepared by a sol-gel method. Expanded perlites were modified using H2SO4 and cetyltrimethylammonium bromide in this experiment. The photocatalytic degradation mechanism of Reactive brilliant blue X-BR by expanded perlites loaded titanium dioxide photocatalysts has been investigated. The samples were characterized by scanning electron microscopy, specific surface area, X-ray diffraction analysis. The photocatalytic activities were evaluated by the photocatalytic oxidation of Reactive brilliant blue X-BR solution. It was found that the prepared expanded perlite loaded titanium dioxide photocatalysts have an excellent photocatalytic under ultraviolet illumination. The results of ultraviolet spectrum and infrared absorption spectrum showed that the anthraquinone structures and benzene rings were destroyed under photocatalytic oxidation reaction. The identification by gas chromatography-mass spectrometer analyses indicated that H2O and carbon dioxide could be the primary degradation products.
关键词： Reactive brilliant blue X-BR,Expanded perlites,Photocatalytic degradation mechanism,TiO2
更新于2025-09-09 09:28:46
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Fabrication of highly efficient and hierarchical CdS QDs/CQDs/H-TiO2 ternary heterojunction: Surpassable photocatalysis under sun-like illumination
摘要： Highly efficient and durable visible-light utilized nanocomposites have a vital role in environmental pollutants remediation. Hence, in this study, we have fabricated CdS QDs co-sensitized CQDs/H-TiO2 (Hollow Titania) ternary heterostructures (CdS QDs/CQDs/H-TiO2) in a facile region-selective deposition route. The as-fabricated nanocomposites were evidently characterized by physicochemical techniques. CdS QDs were uniformly distributed on the smooth surface of hierarchical CQDs/H-TiO2 heterojunction. The as-fabricated CdS QDs/CQDs/H-TiO2 nanocomposite has high-performances for efficient degradation efficacy of phenol, MB and RhB which exhibited enhanced degradation activities with rate constants (k) of 0.03, 0.051 and 0.045 min-1, respectively. All these superior photocatalytic activities obviously attributed to the effect of calcination temperature, enhanced photocurrent, minimized recombination of photo-induced charges in the photocatalysis and optimum content of CdS QDs have the distinct basis for the close interfacial connection developing. In addition, evidenced on the arguable results of electron spin resonance and radical-trapping experiments, the primary reactive-oxygen species and a plausible reaction-mechanism for organic pollutants degradation over CdS QDs/CQDs/H-TiO2 were proposed. This creative work is strategically considered an important step to potentially enhance the utilization of TiO2 in various fields as visible light-induced heterojunction.
关键词： Hollow TiO2,CdS QDs/CQDs/H-TiO2,Visible-light photocatalysis,CQDs/H-TiO2,Environmental remediation
更新于2025-09-04 15:30:14
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Solution combustion synthesis and characterization of phosphorus doped TiO2–CeO2 nanocomposite for photocatalytic applications
摘要： Phosphorus doped TiO2-CeO2 nanocomposite (P-TiO2-CeO2) was synthesized by solution combustion method. The prepared sample has been heated at di?erent temperatures and characterized by X-ray di?raction (XRD), scanning electron microscopy (SEM), UV–vis absorption spectra, X-ray photoelectron spctroscopy (XPS). XRD analysis reveals the retarded phase transition by increased thermal stability due to phosphorus doping. FE-SEM shows the porous structure of the sample. The absorption edge of the P/TiO2-CeO2 nanocomposite exhibits redshift with increasing heating temperature with its value around 2.93 eV, 2.90 eV and 2.89 eV at 400 °C, 500 °C and 600 °C respectively. From the observed P2p XPS peak, it is con?rmed that the doped phosphorus enters substitutionally into Ce4+/Ti4+ site, which can play an important role in the photocatalytic activity of the sample. The binding energy of Ti 2p XPS peak increases slightly from 458.5 eV to 458.8 eV due to interaction between titanium and cerium.
关键词： Phosphorus doping,TiO2,CeO2,XPS,TiO2-CeO2 nanocomposite
更新于2025-09-04 15:30:14
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Effect of TiCl4 Treatment on Different TiO2 Blocking Layer Deposition Methods
摘要： Organolead halid perovskite CH3NH3PbI3 solar cells with all-mesoporous device structure were fabricated with TiO2 blocking layer created by two different methods. Three groups of devices were tested. The TiO2 blocking layer of group 1 was spin-coated with conventional method, while that of groups 2 and 3 was grown by magnetron sputtering of metallic Ti and followed thermal oxidation. Different durations (0, 30, 45, and 60 minutes) of TiCl4 treatment were used during fabrication to study how the performance of each group of solar cells was affected. For all groups of samples, it was obvious that treated samples had much better I-V characteristics that non-treated, with up to 50% improvement in PCE. The difference in the performance improvement was investigated.
关键词： TiCl4 treatment,Perovskite Solar Cells (PSCs),TiO2 blocking layer
更新于2025-09-04 15:30:14
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Effect of Anodization Parameters on the Surface Morphology and Photoelectrochemical Properties of TiO2 Nanotubes
摘要： Titanium sheets are anodized to prepare titanium dioxide nanotubes (TiO2 NTs) with varying chemical polishing times, anodizing voltages, anodizing times and NH4F electrolyte concentrations. The surface morphology of the TiO2 NTs is observed by a Scanning Electron Microscope (SEM) and used to characterize the inner diameter (di), centre to centre distance (l) and wall thickness (w). The photoelectrochemical performance of TiO2 NT arrays is described by measurements of the photocurrent density and the incident photon to current efficiency (IPCE). The data show l can be controlled by the anodizing voltage; in contrast, di and w are influenced by the anodizing time and NH4F electrolyte concentration. Furthermore, the effects of the anodization parameters on the TiO2 NTs’ surface morphology were determined to influence each other. Using the optimum condition of an anodizing voltage of 60 V at 60 min in 0.125 mass % NH4F ethylene glycol, TiO2 NTs were fabricated that showed a photocurrent density of 90.42 μA /cm2 and maximum IPCE of 18.76 % at 300 nm. The results indicate that the effects of the anodization parameters on the photocurrent response of TiO2 NTs are primarily achieved through control of the wall thickness and the ratio of the diameter to the wall thickness (di / w). For a wall thickness that is greater than a critical value, the ratio di / w can reach a range in which the TiO2 NTs show a high photocurrent output.
关键词： surface morphology,wall thickness,TiO2 nanotubes,anodization,photoelectrochemical property
更新于2025-09-04 15:30:14
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Synthesis of Al-MCM-41@Ag/TiO <sub/>2</sub> Nanocomposite and Its Photocatalytic Activity for Degradation of Dibenzothiophene
摘要： Mesoporous Al-MCM-41@Ag/TiO2 nanocomposites were synthesized successfully by combining the sol-gel method and hydrothermal treatment, using titanium isopropoxide (TTIP), AgNO3, and Vietnamese bentonite as precursors of Ti, Ag, and Si, respectively. The synthesized materials were well characterized by X-ray powder di?raction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption isotherm measurements, energy dispersive X-ray spectroscopy (EDX), UV-visible di?use re?ectance spectroscopy (UV-Vis/DRS), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity was evaluated by the photodegradation of dibenzothiophene (DBT) under both UV and visible light irradiation. MCM-41@Ag/TiO2 catalyst exhibited high catalytic activity for the oxidative desulfurization (ODS) of DBT reaching almost 100% conversions at 50°C after 2 h under UV and visible light irradiations. The signi?cant enhanced degradation of DBT over Al-MCM-41@Ag/TiO2 might be due to the synergy e?ects of high surface area of MCM-41, well-distributed TiO2 anatase, and reduced electron-hole recombination rates due to the dispersion of Ag nanoparticles.
关键词： photocatalytic activity,Al-MCM-41@Ag/TiO2,dibenzothiophene,visible light irradiation,oxidative desulfurization
更新于2025-09-04 15:30:14