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Effect of Sputtering Technique and Properties of TiO2 Doped with SnO2 Thin Films
摘要： Doped oxide materials of 90% of TiO2 was doped with 10% of SnO2 that target has been deposited at a substrate temperature of 250°C for 1 hour by using DC Sputtering technique. The as synthesized target was TiO2-SnO2 was used to deposit on the glass substrates. The deposited oxide thin film was characterized for their structural, surface morphological, electrical and optical properties. X-ray diffraction is used for studying the nature and structure, scanning electron, atomic force microscopy and transmission electron microscopy are used to identify the surface morphology of the prepared films. The Van der Pauw technique is employed to measure electrical resistivity and Hall mobility of the film. Wide varieties of methods are available for measuring thin film thicknesses. Stylus profilometry will be helpful to find the thickness of the film, structural studies by X-ray, and micros structural analysis of the film.
关键词： Scanning Electron microscopy (SEM),Stylus profilometry,TiO2-SnO2,X-ray diffraction (XRD),UV-Vis-NIR spectrometer
更新于2025-09-04 15:30:14
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TiO <sub/>2</sub> :Sm <sup>3+</sup> based luminescent oxygen sensitive probes in LDPE packaging material
摘要： In present work it was attempted to prepare luminescent TiO2:Sm3+ microprobes embedded into low density polyethylene (LDPE) films for real-time non-intrusive detection of oxygen contamination in plastic film of food packages with a long term goal of streamlining the quality control mechanisms in food packaging process. The luminescence of TiO2:Sm3+ has previously been reported to be a usable for optical sensing of O2 and other gases [1]. In current work we also show that its thermal stability makes it especially suitable for thermo polymer industry as it can withstand required thermal treatments encountered in different polymer processing stages without losing its ability to function as an O2 probe. Sol–gel-prepared TiO2:Sm3+ microparticles were embedded into LDPE by direct mixing [2] and hot pressing the polymer in molten state. The optical response of the doped films to various O2 ambient concentrations are reported in comparison to pristine TiO2:Sm3+ powder. The shortcomings in the sensor performance due to poor oxide particle size control must be paid attention in the future.
关键词： extrusion,LDPE,Sm3+,oxygen sensor,TiO2
更新于2025-09-04 15:30:14
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Periodic TiO2 Nanostructures with Improved Aspect and Line/Space Ratio Realized by Colloidal Photolithography Technique
摘要： This paper presents substantial improvements of the colloidal photolithography technique (also called microsphere lithography) with the goal of better controlling the geometry of the fabricated nano-scale structures—in this case, hexagonally arranged nanopillars—printed in a layer of directly photopatternable sol-gel TiO2. Firstly, to increase the achievable structure height the photosensitive layer underneath the microspheres is deposited on a re?ective layer instead of the usual transparent substrate. Secondly, an increased width of the pillars is achieved by tilting the incident wave and using multiple exposures or substrate rotation, additionally allowing to better control the shape of the pillar’s cross section. The theoretical analysis is carried out by rigorous modelling of the photonics nanojet underneath the microspheres and by optimizing the experimental conditions. Aspect ratios (structure height/lateral structure size) greater than 2 are predicted and demonstrated experimentally for structure dimensions in the sub micrometer range, as well as line/space ratios (lateral pillar size/distance between pillars) greater than 1. These nanostructures could lead for example to materials exhibiting ef?cient light trapping in the visible and near-infrared range, as well as improved hydrophobic or photocatalytic properties for numerous applications in environmental and photovoltaic systems.
关键词： TiO2,sub-wavelength structures,sol-gel,colloidal photolithography
更新于2025-09-04 15:30:14
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Photodegradation of Methyl Orange Over CdS–TiO2/L-zeolite Composite Photocatalyst
摘要： A stable and active composite photocatalyst CdS–TiO2/L-zeolite has been synthesized through sol–gel method. The composite photocatalyst exhibits enhanced light harvesting in visible region indicating the improved photoresponsive ability because of CdS dopant. Photocatalytic conditions, such as the doping quantity of CdS, the concentration of photocatalyst, initial pH values and concentrations of methyl orange solutions have been systematically studied to obtain the highest photocatalytic efficiency. Photocatalytic kinetics of the composite photocatalyst is proved to conform to the first-order equation. The mechanism of the photocatalytic process is proposed in this work. L-zeolite support and CdS dopant could prevent the undesired electron/hole recombination and promote charge separation aiding for the continuous generation of active radicals. The novel composite photocatalyst shows good promise for applications in degrading environmental pollutants.
关键词： TiO2,Composite photocatalyst,Stability,CdS doping,L-zeolite
更新于2025-09-04 15:30:14
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Reference Module in Chemistry, Molecular Sciences and Chemical Engineering || Interface Potentials, Intrinsic Defects, and Passivation Mechanisms in Al 2 O 3 , HfO 2 , and TiO 2 Ultrathin Films
摘要： For the tailoring of interface properties in terms of providing active centers for surface reactions, surface passivation, or the adjustment of surface potentials, ultrathin metal oxide surface coatings are of importance. In this contribution we report about the applicability of Al2O3, HfO2, and TiO2 ultrathin films prepared by atomic layer deposition (ALD) regarding the aforementioned items. We have selected these metal oxides because of their wide field of applications. HfO2 is the main competitor for the replacement of SiO2 in microelectronic devices.1,2 Al2O3 ALD films are applied for passivation schemes in silicon-based3 and more recently perovskite solar cells.4 TiO2 is, for example, attractive for resistive switching devices5 and as active or passive layer in energy conversion applications such as solar cells6 or water splitting devices,7,8 to name a few. Here, the use of the ALD technique brings advantages such as: (i) precise thickness control to optimize the trade-off between light absorption (in a range of depletion layer) and charge separation (thinner thickness),7 (ii) high conformity to coat complex structures accompanied by increased light absorption,7 and (iii) capability to control the band-gap narrowing by doping with W7 or N9,10 and hence allow visible light absorption.
关键词： Al2O3,HfO2,TiO2,ultrathin films,interface potentials,intrinsic defects,passivation mechanisms,atomic layer deposition
更新于2025-09-04 15:30:14
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Preparation of TiO2 Microspheres with Tunable Pore and Chamber Size for Fast Gaseous Diffusion in Photoreduction of CO2 under Simulated Sunlight
摘要： TiO2 microsphere with tunable pore and chamber size are prepared by a simple solventhermal method and used as catalyst for the photocatalytic CO2 reduction. It is found that the hollow microsphere with relative lower surface area of 73.8 m2g-1 exhibits increased pore size of 18.1 nm and cavity structure, leading to higher CO2 diffusion coefficient of 5.40×10-5 cm2s-1 compared with the solid and yolk/shell microspheres. Therefore, the hollow microsphere possesses more accessible sites for CO2 adsorption, which finally gives rise to the enhanced CO production rate of 10.9±0.7 μmolg-1h-1 under simulated sunlight, which is respectively 1.6 and 1.4 times higher than that of solid and yolk/shell microspheres. Electron dynamic study further demonstrates that hollow microsphere shows the highest photocurrent density and the lowest charge recombination among three microspheres structure, which is attributed to the swift CO2 diffusion providing fresh CO2 molecules to rapidly scavenge the photo-generated electrons and finally leading to the excellence catalytic reduction performances. This method could be adopted as a general strategy to prepare high performance TiO2 catalysts with desirable structural qualities for the photocatalytic CO2 reduction under nature sunlight.
关键词： TiO2,CO2 reduction,Hollow structures,Photocatalysis,Mass transport
更新于2025-09-04 15:30:14
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Construction of Ti3+ self-doped TiO2/BCN heterojunction with enhanced photoelectrochemical performance for water splitting
摘要： Ti3+ self-doped TiO2/BCN heterojunction (Ti3+-TiO2/BCN) was constructed via a hydrothermal method with using NaBH4 as reducing agent. The BCN nanosheets function as a good support to block the agglomeration of Ti3+-TiO2 nanoparticles, which decreased the recombination of photogenerated charge carriers. The Ti3+-TiO2/BCN sample exhibited enhanced electronic conductivity and absorption in visible light region because of the introduction of Ti3+ and oxygen vacancies (Ov). The as-prepared Ti3+-TiO2/BCN sample showed enhanced photoelectrochemical (PEC) performance as confirmed by analyses of LSV, EIS, Bode plots and M–S. Under the visible light irradiation, the optimally Ti3+ self-doped TiO2/BCN heterojunction sample yield a photocurrent density of ～ 0.69 mA/cm2 at 1.23 V versus RHE, which is over three times as high as BCN and TiO2/BCN at the same conditions.
关键词： hydrothermal method,photoelectrochemical performance,NaBH4,water splitting,Ti3+ self-doped TiO2/BCN heterojunction
更新于2025-09-04 15:30:14
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Pd/TiO2 @ Carbon Microspheres Derived from Chitin for Highly Efficient Photocatalytic Degradation of Volatile Organic Compounds
摘要： Facing the serious air pollution caused by the volatile organic compounds (VOCs), the highly efficient degradation and removal of VOCs have attracted great attentions. To develop efficient novel photocatalysts, Pd/TiO2 @ carbon nanofibrous microspheres were constructed by carbonizing the TiO2/chitin microspheres, followed by immobilizing Pd nanoparticles on the TiO2/carbon microspheres via a green pathway. The composite microspheres were composed of carbon nanofibers, on which TiO2 nanoparticles and ultra-small Pd nanoparticles with mean size of 1 nm were well immobilized and distributed, supported by transmission electron microscope and elemental mappings results. The Pd/TiO2 @ carbon microspheres were used for the gas phase photodegradation of VOCs. The results demonstrated that the conversion of toluene and benzene to CO2 and H2O reached 96.4% and 91.7%, respectively, which were higher than the reported values in the literatures. The combination of TiO2 and Pd nanoparticles played an important role on the enhancement of the catalytic activity. Moreover, the Pd/TiO2 @ carbon microspheres could be recycled and reused. This work provided a new strategy to eliminate VOCs, which was beneficial to a sustainable world.
关键词： catalyst TiO2 nanoparticles,Chitin microsphere,Pd nanoparticles,degradation of volatile organic compounds,carbon nanofibers
更新于2025-09-04 15:30:14
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Enhanced visible-light photoelectrochemical hydrogen evolution through degradation of methyl orange in a cell based on coral-like Pt-deposited TiO2 thin film with sub-2 nm pores
摘要： TiO2 nanoparticles exhibit good photocatalytic activity for hydrogen evolution through water splitting; however, they demonstrate weak activity under visible light irradiation due to the wide band gap of TiO2. Deposition with noble metals such as platinum, as cocatalyst, led to the red-shift of the absorption edge of rutile TiO2; however, its activity is not significant for the photoelectrochemical (PEC) degradation of azo dyes such as methyl orange (MO). Herein, we investigated the photoelectrocatalytic degradation reaction of MO in a PEC cell based on Pt-deposited TiO2 thin film. The performance of the cell increased through the formation of mesoporous coral-like structures with sub-2 nm pores and the formation of defect states on the electrode surface. UV–vis studies confirmed, when methanol was added, the PEC cell exhibited a much higher MO degradation efficiency (99.6% after 28 min UV irradiation) than in the absence of methanol (64.7%). GC–MS studies confirmed the oxidation of methanol to formaldehyde, reacting on the electrode surface, followed by the reduction of the protons into hydrogen over the Pt sites. Also, the conversion of formaldehyde to formic acid and formic acid to CO2 are possible mechanisms to increase the hydrogen evolution rate to 418 μmol/h under visible light irradiation. Reaction of adsorbed active species within the surface of coral-like TiO2 structures with sub-2 nm pores provides high activity of the proposed PEC cell for visible-light-driven water splitting. These research studies may be continued to the design of other efficient semiconductor photocatalysts.
关键词： Photoelectrocatalytic activity,Photoelectrochemical cell,Coral-like TiO2 nanopores,Hydrogen production,Dye degradation
更新于2025-09-04 15:30:14
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Regulation of osteoblast differentiation by osteocytes cultured on sclerostin antibody conjugated TiO2 nanotube array
摘要： Sclerostin is a negative regulator of the Wnt signaling pathway for osteoblast differentiation. In this study, osteoblasts were co-cultured with osteocytes (MLO-Y4 cells) on the surface of sclerostin antibody-conjugated TiO2 nanotube arrays (TNTs-scl). Field emission scanning electron microscopy (SEM), contact angle measurement and confocal laser scanning microscope (CLSM) were employed to characterize the conjugation of sclerostin antibody onto the surface of TiO2 nanotube arrays. The cellular viability and morphology results displayed TNTs-scl (TNT30-scl and TNT70-scl) were beneficial to the growth of MLO-Y4 cells. There was no apparent change in sclerostin gene expression between MLO-Y4 cells grown on TNTs and TNTs-scl. However, TNTs-scl significantly reduced the amount of sclerostin in the medium. In comparison with the control groups, osteoblasts displayed higher differentiation capability when co-cultured with MLO-Y4 cells on the surface TNTs-scl, which was indicated by the ALP activity, mineralization capability as well as expression levels of key proteins in Wnt signaling. This study provides a simple strategy to engineer titanium surface for bone fracture recovery, especially in osteoporotic conditions.
关键词： TiO2 nanotube arrays,osteocytes,osteogenic differentiation,Sclerostin antibody
更新于2025-09-04 15:30:14