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Fabrication of photoactive CaTiO3–TiO2 composite thin film electrodes via facile single step aerosol assisted chemical vapor deposition route
摘要： CaTiO3–TiO2 composite oxide films have been employed, for the first time, as photoelectrodes in photoelectrochemical (PEC) splitting of water. The transparent methanol solutions of Ti(Pro)4 and newly synthesized calcium complex [Ca2(TFA)3(OAc)(PrOH)(H2O)(THF)3] (1) (where TFA stands for trifluoroacetato; OAc stands for acetate; and PrOH stands for isopropanol) were utilized for aerosol assisted chemical vapor deposition (AACVD) of the target films. The composite electrodes were deposited on fluorine doped tin oxide (FTO) coated conducting glass substrates at varying deposition temperatures of 500–600 °C. The resulting films were extensively characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray analysis and scanning electron microscopy. PEC responses of all the composite electrodes were studied under simulated solar irradiation of AM 1.5 G (100 mW cm?2). The CaTiO3–TiO2 photoanode formed at 600 °C showed higher photocurrent density of 610 μA cm?2 at 0.7 V versus Ag/AgCl/3 M KCl reference electrode as compared to the other two electrodes fabricated similarly with only difference of fabrication temperature (i.e., 500 and 550 °C).
关键词： photoelectrodes,photoelectrochemical water splitting,aerosol assisted chemical vapor deposition,CaTiO3–TiO2 composite
更新于2025-09-10 09:29:36
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Electrospinning Construction of Flexible Composite Nanoribbons with Color-Tunable Fluorescence
摘要： Herein, we describe the innovative one-dimensional nanomaterials, electrospun composite nanoribbons (width 10.119 ± 0.186 μm) containing complexes of Eu(TTA)3(TPPO)2 and Tb(BA)3phen in a matrix of polymethylmethacrylate (PMMA). Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and fluorescence spectroscopy were used to characterize the final products. The novel luminescent composite nanoribbons exhibit green, orange and red fluorescence emission peaks at 490, 545, 592, and 615 nm, which are ascribed to the 5D4 → 7F6 (490 nm) and 5D4 → 7F5 (545 nm) energy transitions of Tb3+ ions, and the 5D0 → 7F1 (592 nm), 5D0 → 7F2 (615 nm) transitions of Eu3+ ions, respectively. It is observed that the doping percentage and the chosen excitation wavelength could be used to tune the emission color of the samples. The color-tunable luminescent composite nanoribbons have potential applications in the fields of display panels, lasers and bioimaging.
关键词： fluorescence,electrospinning,composite nanoribbons,rare earth complexes,tunable color
更新于2025-09-10 09:29:36
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Use of iodine for improving phase quantification using x-ray tomography
摘要： X-ray computed tomography (CT) has been used to quantify pore structure and crack characterization in cementitious materials. However, similar contrast (greyscale values) of the hydration products in the reconstructed image volume has limited the ability to quantify these phases, and this remains a significant need to further the impact of this experimental method. The goal of this research was to improve the ability to quantify synthesized hydration products by incorporating a contrast agent to improve segmentation between the four main hydration products in portland cement; C-S-H, calcium hydroxide (CH), monosulfate (AFm), and ettringite (AFt). Pure C-S-H, CH, and AFt, and a pure and modified AFm, with iodine as a contrast agent, were synthesized for investigation by x-ray CT. Multi-energy scans were used to isolate individual phases using a synchrotron radiation facility. Using iodine as a contrast agent resulted in accurate quantification of the four main hydration products.
关键词： Composite (E),Hydration products (B),Image analysis (B),X-ray tomography,Cement (D)
更新于2025-09-10 09:29:36
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FeSiAl/ZnO-filled resin composite coatings with enhanced dielectric and microwave absorption properties
摘要： Composite coatings with resin matrix and hybrid fillers of FeSiAl and ZnO powders have been developed for their potential application as microwave absorbing coatings. The effects of FeSiAl and ZnO content on the complex permittivity, complex permeability and reflection loss (RL) of such composite coatings were studied in the frequency range of 8.2–12.4 GHz (X-band). Compared with the complex permeability, the complex permittivity showed more dependence on the absorbent content and the permittivity values increase notably with increasing FeSiAl or ZnO content. Owing to the best impedance matching and appropriate electromagnetic attenuation, the composite coating filled with 35 wt% FeSiAl and 20 wt% ZnO powders exhibits the most desirable microwave absorption properties with the effective absorption bandwidth (< ?10 dB, > 90% absorption) 3.5 GHz in 8.6–12.1 GHz and the strong absorption peak ?40.5 dB at 10.4 GHz, when the thickness is 2.2 mm. The results suggest that FeSiAl/ZnO-filled resin composite coatings could be qualified as good candidates for highly efficient and strong microwave absorbing coatings.
关键词： FeSiAl,dielectric properties,resin composite coatings,microwave absorption,ZnO
更新于2025-09-10 09:29:36
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Metal-Enhanced Fluorescence of Gold Nanoclusters as a Sensing Platform for Multi-component Detection
摘要： Metal-enhanced fluorescence (MEF) has been applied to construct biosensing systems in the recent decades owing to its favorable optical properties. Herein, silver nanoparticles (AgNPs) are used to enhance fluorescence of gold nanoclusters (AuNCs), by fabricating a core-shell composite nanostructure Ag@SiO2-AuNCs consisting of a silver core, a silica shell and an outer conjugated layer of AuNCs. The core-shell MEF-capable nanoparticles possess water dispersibility, high stability and good biocompatibility. The interaction between AuNCs on the surface of the outer silica shell and the silver core, significantly improves the excitation efficiency, and thus enhances the fluorescence emission, photostability and quantum yield of the AuNCs. The composite nanoparticle Ag@SiO2-AuNCs provides a fluorescence enhancement of up to 3.21-fold when the separation distance (the thickness of the silica shell) is about 10 nm. Finally, the composite nanostructures have further been applied to develop a sensing platform for multi-component detection based on the MEF capability and the OFF-ON-OFF switching nature of the fluorescence signal, and the detection limits for Cu2+, inorganic pyrophosphate (PPi) and pyrophosphatase (PPase) are 39 nM, 78.7 nM and 0.976 mU, respectively. This platform has been applied to detect Cu2+, PPi and PPase with satisfactory results in living cells.
关键词： Metal-enhanced fluorescence (MEF),Fluorescence sensor,Core-shell composite nanostructure,Gold nanoclusters (AuNCs)
更新于2025-09-10 09:29:36
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Enhanced Visible Photocatalytic Activity of Tree-like ZnO/CuO Nanostructure on Cu Foam
摘要： Novel tree-like ZnO/CuO composite, composed of CuO nanowire trunks and ZnO nanorod branches, have been successfully synthesized on Cu foam substrate. Single-crystalline CuO nanowires and ZnO nanorods are obtained by thermal oxidation and hydrothermal processes, respectively. The morphological, crystal and optical properties of the as-prepared samples have been studied by field-emission scanning microscopy, X-ray diffractometer, transmission electron microscopy, and UV-vis spectrophotometer. The resultant tree-like ZnO/CuO composites on Cu foam show excellent photocatalytic activity with a rate constant of about 0.0073 min-1 in the photo-degradation of Rhodamine B (RhB) under visible light (λ>420 nm). The Cu foam not only provides extra-large surface area for the growth of tree-like CuO/ZnO composites, but also acts as an effective frame to support the catalysts. Furthermore, tree-like ZnO/CuO composite catalysts show high recovery yield for the recycling during the degradation of organic pollutants. This work provides an insight view into the design and synthesis of composite photocatalyst effectively supported by a substrate.
关键词： Cu foam,ZnO/CuO composite,self-supported photocatalyst,visible photocatalytic activity
更新于2025-09-10 09:29:36
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Alveolar TiO2-β-SiC photocatalytic composite foams with tunable properties for water treatment
摘要： New alveolar TiO2-β-SiC photocatalytic composite foams gathering within a ready-to-use media, the TiO2 active phase and the β-SiC alveolar foam structure have been prepared through a Shape Memory Synthesis (SMS) replica method. They have been obtained by incorporating TiO2 powders inside the infiltration slurry used for transforming the pre-shaped polyurethane foam into its corresponding carbide. The photocatalytic composite foams contained 16 wt. % and 24 wt. % of TiO2, most of them being available for the reaction by being located in the external layer of the foam rather than dispersed within the foam matrix, so that no further post-synthesis immobilization process was needed for coating the foam with TiO2 active phase. The adsorption behaviour of the TiO2-β-SiC composite foams towards the Diuron pollutant in water was tuned by applying a final calcination treatment to the as-synthesized foams within the 400-700 °C range, that allowed to tune the amount of residual unreacted carbon within the foams, while allowing the formation of small TiO2 crystallites via the selective oxidation of TiC carbide, and thanks to the β-SiC resistance to oxidation. The TiO2-β-SiC composite foams calcined at 700 °C outperformed a reference β-SiC supported foam TiO2 catalyst in terms of diuron degradation, while the reference foam remained more efficient in terms of mineralization rate.
关键词： water treatment,photocatalysis,Shape Memory Synthesis replica method,adsorption properties,TiO2-β-SiC composite foam
更新于2025-09-10 09:29:36
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Photoelectrocatalytic decolorization of azo dyes with nano-composite oxide layers of ZnO nanorods decorated with Ag nanoparticles.
摘要： Photoelectrocatalysis provides an excellent frame for the application of photocatalytic nanostructured materials on easy recoverable supports. This study reports the two-step synthesis of hierarchically nanostructured ZnO/Ag composite photoelectrodes. Wutzite ZnO was selectively electronucleated as spheroidal seeds on fluor doped tin oxide substrates and nanodecorated with Ag nanoclusters under electrochemical control. Hirearchically organized nanorods were selectively chemically grown on the plane (002) perpendicular to the substrate from ZnO/Ag seeds. Solutions emulating dye effluents with the usual contents of 0.1 M of NaCl and a model azo dye (Methyl Orange) were decolorized using ZnO/Ag nanorods in different treatments. Photocatalysis attained discrete decolorizations of 8% whereas photoelectrocatalysis completely decolorized solutions after 60 min. The influence of the metal/semiconductor interface (ZnO/Ag) as introduced Schottky barrier is studied demonstrating a four-fold enhancement on decolorization kinetics respect bare ZnO nanorods. The influence of the seed growth control on the final photoelectrocatalytic response is reported to control the hierarchical organization of nanorods. This resulted in different decolorization kinetics as result of the differences on the efficient use of the delivered photons conditioned by the photoelectrode structure.
关键词： photocatalysis,photocathode,nano-coating,electrochemical water treatment,Metallic/semiconductor composite photocatalysts
更新于2025-09-10 09:29:36
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Enhanced Sensing Performance to Toluene and Xylene by Constructing NiGa2O4-NiO Heterostructures
摘要： The selective detection of methyl benzene (e.g. toluene and xylene) using oxide semiconductor-based gas/vapor sensors is highly desirable but limited by the low chemical reactivity of the benzene compounds. Exploiting p-type semiconductor oxides (e.g., NiO) which provide distinctive catalytic activities for methyl benzene detection is an essential approach. However, the intrinsic responses of p-type semiconductor oxides are often low. In this paper, high-performance toluene and xylene detection has been realized by a sensor based on novel p-p heterojunction NiGa2O4-NiO nanospheres. Construction of optimized p-p heterojunctions, which resulting from the rationally controlling of the NiGa2O4 content in NiGa2O4-NiO, leads to significantly promoted sensing properties for toluene and xylene detection. It is found that the sensor based on 50% NiGa2O4-NiO exhibits the best sensing performances. Its highest response (Rg/Ra = 12.7 to toluene; Rg/Ra = 16.3 to xylene) is almost 10 times higher than that of the pure NiO (Rg/Ra < 2) to 100 ppm toluene and xylene at 230 oC. More importantly, the sensor exhibits superior selectively for detection of the methyl benzene even against more reactive interfering gases/vapors, such as formaldehyde and ethanol. The p-p oxide heterojunction suggests a promising sensing material for toluene and xylene detection with high response, excellent selectivity, good stability and rapid response/recover time.
关键词： Composite semiconductor,NiO,NiGa2O4,Heterojunction,Xylene,Toluene
更新于2025-09-10 09:29:36
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AIP Conference Proceedings [Author(s) 6TH INTERNATIONAL CONFERENCE ON PRODUCTION, ENERGY AND RELIABILITY 2018: World Engineering Science & Technology Congress (ESTCON) - Kuala Lumpur, Malaysia (13–14 August 2018)] - Hydrothermal synthesis of carbon dots and their luminescence
摘要： The synthesis of carbon dots by hydrothermal method with external heating from precursors such as glucose, citric acid, birch bark soot, cowberry, blueberry, redcurrant, and blackbird cherry are investigated. The photoluminescence studies of these carbon dots at di?erent excitation wavelengths was held. It is shown that there is an e?ect of the shift of luminescence spectra intensity peaks with the increasing of excitation wavelengths. The presence of this e?ect open new perspectives for development of composite materials from carbon dots, starch, and epoxy, which can convert the light of the blue LED into the green.
关键词： composite materials,luminescence spectra,hydrothermal synthesis,carbon dots,photoluminescence
更新于2025-09-10 09:29:36