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Label-free immunosensors based on a novel multi-amplification signal strategy of TiO2-NGO/Au@Pd hetero-nanostructures
摘要： A label-free electrochemical immunosensor for quantitative detection of human epididymis specific protein 4 antigen (HE4 Ag) was developed by a novel multi-amplification signal system. The multi-amplification signal system was formed by loading bimetallic Au@Pd holothurian-shaped nanoparticles (Au@Pd HSs) on titanium oxide nanoclusters functionalized nitrogen-doped reduced graphene oxide (TiO2-NGO). The Au@Pd HSs were obtained via seed-mediated approach with in-situ grown palladium nanoarms on gold nanorods (Au NRs) surfaces, which possessed good electrocatalysis for hydrogen peroxide (H2O2) reduction and excellent biocompatibility. The TiO2-NGO with the high catalytic activity and large specific surface area was synthesized by hydrothermal method. Using H2O2 as an electrochemically active substrate, the prepared label-free electrochemical immunosensor based on the TiO2-NGO/Au@Pd HSs hetero-nanostructures as the signal amplification platform exhibited excellent selectivity, reproducibility and stability for the detection of HE4 Ag. Meanwhile, the linear range from 40 fM to 60 nM with the detection limit of 13.33 fM (S/N = 3) was obtained, indicating the immunosensor offers a promising method for clinical detection of HE4 Ag.
关键词： Au@Pd nanoparticles,Titanium oxide,Label-free electrochemical immunosensor,Nitrogen-doped reduced graphene oxide,Human epididymis specific protein 4
更新于2025-09-23 15:23:52
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Photoactive Gel for Assisted Cleaning during Olive Mill Wastewater Membrane Microfiltration
摘要： A photoactive gel has been fabricated on the surface of polyethylene membranes for enhancing the fouling resistance during olive mill wastewater treatment. Light and pH responsive materials have been introduced in the membrane surface through the build up of a layer-by-layer pattern, which is formed by photocatalytic nanoparticles and ionic polyelectrolytes. The best working conditions to contrast foulants adsorption have been explored and identified. Repulsive interfacial forces and assisted transfer of foulants to catalytic sites have been envisaged as crucial factors for contrasting the decline of the flux during microfiltration. Tests in submerged configuration have been implemented for six continuous hours under irradiation at two different pH conditions. As a result, a worthy efficiency of the photoactive gel has been reached when suitable chemical microenvironments have been generated along the shell side of the membranes. No additional chemical reagents or expensive back-flushing procedures have been necessary to further clean the membranes; rather, fast and reversible pH switches have been enough to remove residues, thereby preserving the integrity of the layer-by-layer (LBL) complex onto the membrane surface.
关键词： submerged microfiltration,layer-by-layer,titanium oxide nanoparticles,water treatment,self-cleaning
更新于2025-09-23 15:23:52
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Water-soluble titanium-oxides: Complexes, clusters and nanocrystals
摘要： The water-soluble titanium-oxide structures covered in this review span a continuum from molecular clusters to colloidal nanocrystals. Here, a deliberate distinction is made between titanium clusters and nanoparticles with organic ligands, soluble in organic solvents, and related structures prepared and soluble in water. This distinction is made in response to rapid developments in three areas covered in this article: small titanium-oxide clusters prepared at low pH values in water, heterpolytungstate macroanions with high-nuclearity titanium-oxide cores, and polyoxometalate complexes of anatase-phase TiO2. The latter nanostructures occupy a unique position between polyoxometalate macroanions and traditional colloidal TiO2. As such, the progressively larger water-soluble titanium-oxide structures covered in the three main sections of this review establish a continuum that begins to blur the longstanding divide between molecular and colloid science.
关键词： Polyoxometalates,Titanium oxide,Water soluble,Clusters,Nanocrystals
更新于2025-09-23 15:23:52
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Development of a photocatalytic filter to control indoor air quality
摘要： Background: The aim of this work was the development and characterization of a photocatalytic filter for the treatment of indoor air, characterized by a low pressure drop. Methods: The filter (photocatalytic filter) was based on a polyester substrate additivated with active carbon (Carbotex 150-6), treated with a sol of titanium dioxide (Sol 121-AB; NextMaterials Ltd.) and illuminated with UV LEDs to induce photocatalytic activity. Results: Tests showed that this filter, used in a suitable device for air circulation with a very low noise level, had the ability to block solid particulates, to photocatalytically oxidize a major fraction of volatile organic compounds (VOCs) and deactivate all of the bacteria blocked on the filter, in contrast to traditional commercial air filters on which the bacteria remain viable. Conclusions: Activated charcoal filters treated with TiO2 and illuminated by UV LEDs were found to be extremely effective in killing bacteria and effective in decreasing VOC and total suspended particulates (TSP).
关键词： Bacteria,Titanium oxide,Photocatalysis,Filters,Total solid particulate,Volatile organic compounds
更新于2025-09-23 15:23:52
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Facile Sol-gel Synthesis of Metaloxide Nanoparticles in a Cellulose Paper Template
摘要： Ensembles of free standing particles of titanium, zinc, copper and iron oxides of 6-109 nm in size were sol-gel synthesized with a use of a cellulose paper as a template. The calcination time as short as 60 min at 550°C in air was found to be sufficient for the formation of crystalline single phase TiO2 or ZnO nanoparticles, Cu2O+CuO or Fe2O3+Fe3O4 nanocomposites and to burn out the organic components. The impurities initially present in the cellulose (Сa, Na, Cl) were detected in the synthesized compounds.
关键词： Sol-gel synthesis,Zinc oxide,Nanoparticle,Copper oxides,Cellulose,Iron oxides,Titanium oxide
更新于2025-09-23 15:22:29
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The photocatalytic degradation kinetics of gaseous formaldehyde flow using TiO2 nanowires
摘要： A high performance TiO2 nanowires photocatalyst was successfully prepared by a hydrothermal method to decompose gaseous formaldehyde into CO2 and H2O in a homemade tube reactor without secondary pollution under UV irradiation. The photocatalytic oxidization (PCO) kinetics fit well with the traditional Langmuir-Hinshelwood-Hougen-Watson (LHHW) model. Multiple parameters including formaldehyde concentration, flow rate, and light intensity were monitored online and proved to be key factors affecting the rate in the photocatalytic reactions. The crystallinity of photocatalyst and its surface reactive site density determined the adsorption equilibrium constant (KHCHO) of formaldehyde on TiO2. The experimental results show that the degradation kinetics of mobile gas-phase formaldehyde by TiO2 nanowires did not strictly conform to the first-order reaction kinetics, and its photocatalytic degradation rate increases with the increase of ultraviolet LED irradiation intensity. It takes only 8.6 minutes to completely degradate formaldehyde at a flow rate of 50 ml/min by 50 mg 700TiO2, and the reaction performance remains unchanged during the decomposing process of 1200 minutes.
关键词： reaction kinetics,formaldehyde,Titanium oxide nanowires,photocatalyst,photocatalytic oxidization
更新于2025-09-23 15:22:29
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Surface characterization of clean SrTiO <sub/>3</sub> (100) substrates by x-ray photoelectron spectroscopy
摘要： The authors analyze the x-ray photoelectron spectra of SrTiO3(100) (STO) substrates to clarify the electronic structure characteristics induced by a sputter–anneal procedure. The survey spectra, the valence band spectra, and the relevant core level spectra, i.e., Sr 3s, Sr 3p, Sr 3d, Sr 4s, Sr 4p, Ti 2p, Ti 3s, Ti 3p, O 1s, and O 2s along with their satellite structures, of both pristine and sputtered and annealed STO have been measured. A comparison of spectra reveals the appearance of new features in the Ti 2p spectra of sputtered and annealed STO, corresponding to Ti3+ states and gap states near the Fermi energy. The presence of Ti3+ states points to the formation of a two-dimensional electron system at the STO surface generated by Ar+ sputtering and annealing in vacuum. Furthermore, the sputter-annealed surface shows only minor carbon contamination as compared to that of the pristine substrate.
关键词： XPS,transition metal oxide,sputtering,2DES,strontium titanium oxide,core level,single crystal
更新于2025-09-23 15:21:01
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Femtosecond laser irradiation of titanium oxide thin films: accumulation effect under IR beam
摘要： This paper discusses the mechanisms of laser-induced periodic surface structures (LIPSS) formation using a high repetition rate femtosecond laser beam irradiation of magnetron-sputtered titanium oxide thin films (TiO1.8) grown onto SiO2/Si substrates. An Yb:YKW 500 fs linearly polarized laser emitting at a wavelength, λ, of 1030 nm, was used to irradiate the films (300 nm thickness) at a repetition rate of 100 kHz under both static and dynamic (scanning) conditions. Under static beam conditions, an incubation behavior related to materials in thin film form was established with a damage threshold of 72 mJ/cm2. Close to this fluence value and increasing the number of laser shots from 1 to 1000, micro-cracking occurred and propagated inside the beam waist diameter zone estimated close to 60 μm. In addition, using a higher fluence value of 280 mJ/cm2, i.e., well above the damage threshold, a melting occurred in an intermediate zone within the irradiated area, with a surprising ‘cure effect’ that contributes to the micro-cracks stabilization. Simultaneously, at the center of the Gaussian laser beam spot, the entire film ablation was observed. Furthermore, irradiation under dynamic mode with a scanning speed of 4 mm/s and a repetition rate of 100 kHz were achieved for the large-scale processing of the TiO1.8 films up to surface area of 25 × 25 mm2. For these irradiation conditions case that correspond to a fluence of 110 mJ/cm2 and a cumulative number of shots of 3000, 2D-LIPSS nano-cracks (200 nm length and λ/8 to λ/9 period) are obtained over the whole irradiated surface, a phenomenon that is mainly attributed to a thermo-mechanical ablation mechanism.
关键词： Femtosecond laser beam,Titanium oxide film,Micro/nano-cracks,High repetition rate,Incubation,LIPSS
更新于2025-09-23 15:21:01
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Properties of Thermally Evaporated Titanium Dioxide as an Electron-Selective Contact for Silicon Solar Cells
摘要： Recently, titanium oxide has been widely investigated as a carrier-selective contact material for silicon solar cells. Herein, titanium oxide ?lms were fabricated via simple deposition methods involving thermal eVaporation and oxidation. This study focuses on characterizing an /TiO2 electron-selective passivated contact layer with this oxidized method. Subsequently, the SiO2 stack was examined using high-resolution transmission electron microscopy. The phase and chemical composition of the titanium oxide ?lms were analyzed using X-ray di?raction and X-ray photoelectron spectroscopy, respectively. The passivation quality of each layer was con?rmed by measuring the carrier lifetime using quasi-steady-state photoconductance, providing an implied open circuit voltage of 644 mV. UV–vis spectroscopy and UV photoelectron spectroscopy analyses demonstrated the band alignment and carrier selectivity of the TiO2 layers. Band o?sets of ~0.33 and ~2.6 eV relative to the conduction and valence bands, respectively, were con?rmed for titanium oxide and the silicon interface.
关键词： carrier-selective contact cell,band alignment,titanium oxide,electron-selective contact
更新于2025-09-23 15:19:57
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Synergy of the catalytic activation on Ni and the CeO <sub/>2</sub> –TiO <sub/>2</sub> /Ce <sub/>2</sub> Ti <sub/>2</sub> O <sub/>7</sub> stoichiometric redox cycle for dramatically enhanced solar fuel production
摘要： Solar thermochemical approaches to CO2 and H2O splitting have emerged as an attractive pathway to solar fuel production. However, efficiently producing solar fuel with high redox kinetics and yields at lower temperature remains a major challenge. In this study, Ni promoted ceria–titanium oxide (CeO2–TiO2) redox catalysts were developed for highly effective thermochemical CO2 and H2O splitting as well as partial oxidation of CH4 at 900 1C. Unprecedented CO and H2 production rates and productivities of about 10–140 and 5–50 times higher than the current state-of-the-art solar thermochemical carbon dioxide splitting and water splitting processes were achieved with simultaneous close to complete CH4 conversions and high selectivities towards syngas. The underlying mechanism for the exceptional reaction performance was investigated by combined experimental characterization and density functional theory (DFT) calculations. It is revealed that the metallic Ni and the Ni/oxide interface manifest catalytic activity for both CH4 activation and CO2 or H2O dissociation, whereas CeO2–TiO2 enhances the lattice oxygen transport via the CeO2–TiO2/Ce2Ti2O7 stoichiometric redox cycle for CH4 partial oxidation and the subsequent CO2 or H2O splitting promoted by catalytically active Ni. Such findings substantiate the significance of the synergy between the reactant activation by catalytic sites and the stoichiometric redox chemistry governing oxygen ion transport, paving the way for designing prospective materials for sustainable solar fuel production.
关键词： thermochemical CO2 splitting,solar fuel production,density functional theory,Ni promoted ceria–titanium oxide,thermochemical H2O splitting,methane partial oxidation,redox catalysts
更新于2025-09-19 17:15:36