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oe1(光电查) - 科学论文

793 条数据
?? 中文(中国)
  • Ni-P-TiO <sub/>2</sub> nanocomposite coatings with uniformly dispersed Ni <sub/>3</sub> Ti intermetallics: effects of TiO <sub/>2</sub> nanoparticles concentration

    摘要: Ni-P-TiO2 nanocomposite coatings were electrodeposited on copper substrates and influence of TiO2 nanoparticles concentration on the phase structure, morphology, chemical composition, microhardness, and corrosion behaviour of the coatings was investigated. Results demonstrate that Ni3Ti intermetallics form and grow during the electrodeposition of the coatings. This study is the first to report the formation of the intermetallics in the case of electrodeposited Ni-P alloy matrix composite coatings. Moreover, the formation mechanism of the intermetallics is discussed in detail. The formed intermetallics dispersed uniformly throughout the microstructure of the nanocomposite coatings, thereby playing a critical role in improving the mechanical and corrosion-related properties of the coatings. Ni-P-10 g·L?1 TiO2 nanocomposite coating possessing the highest amount of Ni3Ti intermetallic associated with the lowest P content, thereby showing the superior microhardness and corrosion resistance. All in all, the volume fraction of Ni3Ti intermetallics is the dominant factor altering the various properties of the coatings.

    关键词: corrosion behaviour,DC electrodeposition,Ni-P-TiO2 nanocomposite coatings,Ni3Ti intermetallic,mechanical properties

    更新于2025-09-23 15:23:52

  • Carboxylic acid-functionalized TiO <sub/>2</sub> nanoparticle-loaded PMMA/PEEK copolymer matrix as a dental resin for 3D complete denture manufacturing by stereolitographic technique

    摘要: The main goal of the present investigation was to the synthesis of bioactive TiO2 nanoparticle-incorporated poly(methylmethacrylate)/polyetheretherketone nanocomposite for enhanced antibacterial and biocompatibility characteristics with suitable properties for manufacturing 3D printed stereolitographic dental prosthesis. The carboxylic acid-functionalized TiO2 nanoparticles have been dispersed into the copolymer matrixes through emulsion polymerization method, and the structural and morphological properties were investigated by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy, and energy dispersive X-ray (EDX) analytical techniques. The FTIR spectrum of synthesized nanocomposites that shows high intense peaks at 2,970–2,850 cm?1 is related to the symmetric and asymmetric stretching C-H vibration of methyl and methylene groups of the polymer matrix. The microscopic results of nanocomposite exhibited that functionalized nanoparticles were effectively and uniformly dispersed into the polymer matrix in the absence of particle agglomerations, and it has been given excellent killing efficiency of 99% under dark conditions against bacterial pathogens Escherichia coli and Staphylococcus aureus and also exhibited favorable cell compatibility with dental pulp cells. This facile synthesized nanocomposite was efficaciously employed for denture manufacturing with stereolitographic technique.

    关键词: Stereolitographic method,TiO2 nanoparticles,Antibacterial,Dental,Copolymer

    更新于2025-09-23 15:23:52

  • Layer-by-layer self-assembly of polyaniline nanofibers/TiO2 nanotubes heterojunction thin film for ammonia detection at room temperature

    摘要: In this paper, for the first time, polyaniline nanofibers/TiO2 nanotubes (PANI/TiO2) heterojunction thin film has been prepared on Pt interdigital electrodes by layer-by-layer self-assembly method and applied in room temperature NH3 detection. It is found that the optimal self-assembly layer number is three (PANI/TiO2-3) compared to one layer (PANI/TiO2-1) and five layers (PANI/TiO2-5). The PANI/TiO2-3 thin film sensor possesses superior response characteristics compared with our other PANI based sensors, including higher response value (336%@5 ppm NH3), acceptable response/recovery time (110 s/1086 s@5 ppm NH3), low detection limit (0.5 ppm), and remarkable selectivity. The enhanced gas sensing performances could be ascribed to the tremendous variation of the carrier concentration caused by the p-n junctions as well as the increased specific surface area and pore volume. This work not only offers a superb strategy to fabricate heterojunction thin film but also accelerates the development of room-temperature operable NH3 sensors.

    关键词: Ammonia detection,Layer-by-layer self-assembly,Polyaniline/TiO2 heterojunction,Thin film,Room temperature operation

    更新于2025-09-23 15:23:52

  • Highly enhanced photocatalytic H2 evolution of Cu2O microcube by coupling with TiO2 nanoparticles

    摘要: The improvement of photocatalytic performance could be attributed to the formation of p-n heterojunction. Furthermore, the interface effect of Cu2O and TiO2 caused a broader absorbance in visible light region and the lower recombination of photogenerated electron-hole pairs. It is believed that the Cu2O/TiO2 p-n heterojunction composites could provide an alternative method to design highly efficient photocatalysts for solar energy. The yield remained around 92.6% after three cycles. Hydrogen production of the Cu2O/TiO2 (60 wt. %, labeled as CT-60) exhibits the highest enhanced photocatalytic activities in hydrogen production with H2 evolution 3002.5 μmol/g. CT-60 is 103 and 8.5 fold higher than cubic Cu2O and TiO2 nanoparticles, respectively. The photocatalytic performance of the composite was effectively tuned by controlling the amount of TiO2. A Cu2O/TiO2 p-n heterojunctions composite was created via a facile, controllable, and one-pot hydrothermal method based on cubic Cu2O and TiO2 nanoparticles in the presence of dioctyl sulfosuccinate sodium salt (AOT) surfactant. The TiO2 nanoparticles with average edge length of ~10.1 nm were uniformly distributed on the crystal surface of Cu2O cube {100}.

    关键词: superior stability,high hydrogen yield,Cu2O/TiO2,photocatalytic

    更新于2025-09-23 15:23:52

  • Improved charge separation of NiS nanoparticles modified defect-engineered black TiO2 hollow nanotubes for boosting solar-driven photocatalytic H2 evolution

    摘要: NiS nanoparticles (NPs) modified black TiO2 hollow nanotubes (NBTNs) are successfully synthesized via surface hydrogenation and facile solvothermal method. The unique structure with intensified surface and interface characteristic endow NBTNs with more catalytic sites, and increase charge carrier separation efficiency with a extended charge lifetime, overwhelmingly promoting its photocatalytic performance. The resultant NBTNs possess a relatively high surface area and pore size of ~89 m2 g-1 and ~9.8 nm, respectively. The resultants NBTNs exhibit an excellent solar-driven photocatalytic hydrogen rate (3.17 mmol h-1 g-1), which almost as high as that of Pt as cocatalyst, in which the apparent quantum (AQE) yield of 5.4 % (420 nm) is recorded for the NBTNs sample. Moreover, the turnover number (TON) can be up to 116000 within 48 h. And the turnover frequency (TOF) is 2400 for NiS. This novel strategy could provide a better understanding of cocatalyst photocatalytic mechanism, and a scheme simultaneously regulating the morphology and structure of photocatalyst for promoting H2 generation.

    关键词: Mesoporous TiO2 nanotube,Oxygen vacancy defect,NiS cocatalyst,Photocatalysis,Ti3+ self-doping

    更新于2025-09-23 15:23:52

  • Intrinsic Au-decoration on anodic TiO2 nanotubes grown from metastable Ti–Au sputtered alloys—High density co-catalyst decoration enhances the photocatalytic H2 evolution

    摘要: Recent work demonstrated that intrinsic Au nanoparticle decoration of TiO2 nanotube arrays (NTs) can be achieved by electrochemical anodization of Ti–Au alloy substrates. However, for a Ti–Au cast alloy produced by melt-alloying, the Au concentration cannot exceed the solubility limit of Au in Ti of 0.2 at.% – this sets constraints on the intrinsic Au nanoparticle loading on anodic TiO2 NTs. Here we explore “metastable” Ti–Au metal substrates that are produced by Ti and Au cosputtering and we establish Au concentrations that far exceed the solubility limit in cast Ti–Au alloys. We show the use of these “metastable” Ti–Au sputtered layers for the anodic formation of TiO2 NTs with a much higher density of Au nanoparticle loading than using classic alloys. Under optimized conditions (Au nanoparticle density) photocatalytic H2 production from such Au@TiO2 platforms provides a 15 times higher photocatalytic H2 evolution rate than the best rates achieved with conventional alloys.

    关键词: Anodic TiO2 nanotube,Metastable Ti–Au alloy,Sputtering,Anodization,Photocatalytic H2 evolution

    更新于2025-09-23 15:23:52

  • Hierarchical Fe2O3 nanorods/TiO2 nanosheets heterostructure: Growth mechanism, enhanced visible-light photocatalytic and photoelectrochemical performances

    摘要: A novel three-dimensional (3D) Fe2O3 nanorods (NRs)/TiO2 nanosheets (NSs) heterostructure is fabricated by employing the TiO2 NSs with dominant high-energy {0 0 1} facets as synthetic template via the facile hydrothermal and chemical bath deposition methods. The structure, morphology and optical property of 3D Fe2O3/TiO2 composites are examined, and the results demonstrate that these samples have pure phase, high crystallinity and good visible-light response. Furthermore, all Fe2O3/TiO2 composites exhibit the superior photocatalytic and photoelectrochemical (PEC) performances compared to pure TiO2 NSs, which should be ascribed to the larger surface area, better optical absorption and efficient electron-hole separation of 3D Fe2O3/TiO2 heterostructure. Among Fe2O3/TiO2 composites, the sample T3 obtained by using 0.05 M iron nitrate at 90 °C for 100 min exhibited the best visible-light photocatalytic activity and PEC performance, which achieves 89.3% photodegradation of Methyl Blue within 120 min and 2.39 mA cm?2 photocurrent density at a potential of 0 V, respectively. The photocatalytic degradation efficiency and photocurrent density of T3 are 1.83 and 11.95 times higher than that of pure TiO2 NSs. In addition, the detailed growth mechanism of Fe2O3 nanomaterials onto TiO2 NSs and the optimization mechanism of photocatalytic and PEC performances are also discussed in present paper.

    关键词: Photoelectrochemical,Photocatalytic,Visible-light,TiO2 nanosheets,Fe2O3/TiO2 heterostructure

    更新于2025-09-23 15:22:29

  • Highly enhanced photoelectrochemical cathodic protection performance of the preparation of magnesium oxides modified TiO2 nanotube arrays

    摘要: The magnesium oxide modified TiO2 nanotube arrays (TiO2 NTs) was prepared to investigate the photoelectrochemical (PEC) cathodic protection performance to 304 stainless steel (SS 304). With the annealing treatment at different temperature, the surface of the modified materials changed remarkably. The film-like Mg(OH)2 obtained at 400 °C transformed to MgO particles after treatment at 500 °C and 600 °C. Further thermal processing at 700 °C enables MgTixOy@TiO2 shell-core structure. Using photoelectrochemical approaches to study the series samples, the cathodic protection performance of the modified TiO2 NTs has significantly improved. The magnesium oxides modified TiO2 NTs treated at 600 °C (Ti-Mg-O 600) shows the best PEC cathodic protection to the underneath steel. Further investigation shows that the highly enhanced PEC cathodic protection performance of Ti-Mg-O 600 was attributed to the effective separation of photogenerated carriers, the increase of carrier concentration and the negative shift of the conduction band potential.

    关键词: Magnesium oxides,Modified TiO2,TiO2 nanotube arrays,Photoelectrochemical cathodic protection

    更新于2025-09-23 15:22:29

  • Development of Titanium Dioxide (TiO <sub/>2</sub> )-Embedded Buoyant Photocatalyst Balls Using Expanded Polystyrene

    摘要: A new immobilization technique of nanoscale TiO2 powders to expanded polystryrene (EPS) balls with temperature-controlled melting method was developed for mass production, and the characterization of TiO2 powder-embedded EPS (TiEPS) balls was evaluated. Based on the scanning electron microscope (SEM) images and associated energy-dispersive X-ray spectroscopy (EDX) analysis, the components of intact EPS balls are carbon and oxygen whereas those of TiEPS balls are carbon, oxygen, and titanium, indicating that TiO2 powders were embedded on the surface of EPS balls. As also evident by the X-ray diffraction (XRD) and FTIR analyses, no significant changes in crystalline structure of TiO2 powders embedded on the EPS balls were found during the preparation and application processes of TiEPS balls. These characterization results indicated that the patches of TiO2 powders were soundly impregnated over the surface of EPS balls without the significant changes in crystalline structure of TiO2 powders and both structural changes and deformation of EPS polymer.

    关键词: FTIR,TiO2-Embedded EPS Balls,Photocatalyst,Methylene Blue (MB),Expanded Polystyrene (EPS),X-ray Spectroscopy,TiO2

    更新于2025-09-23 15:22:29

  • [IEEE 2018 International Semiconductor Conference (CAS) - Sinaia, Romania (2018.10.10-2018.10.12)] 2018 International Semiconductor Conference (CAS) - Enhanced Photoconductivity of SIGE-Trilayer Stack by Retrenching Annealing Conditions

    摘要: We studied the effect of short term furnace annealing over the photoconductive properties of tristacked layer i.e. TiO2/(SiGe/TiO2)3. The structure was prepared by depositing alternate layers of TiO2 and SiGe films, using sputtering technique. A direct-current magnetron transmission electron microscopy and grazing incidence spectroscopy was used to analyze the morphology of the structure. Photoconductive properties were studied by measuring photocurrent spectra at different applied voltages and temperatures. Tristack layers were obtained with 5-10 nm SiGe nanocrystals (NCs) by annealing at 600 °C for 5 min. No sign of SiO2 formation was found inside stacked layers. A maximum in the photocurrent spectra was observed at 994 nm at 300 K but it red-shifted gradually to 1045 nm with decrease in temperature to 100 K. This transition in peak maxima is attributed to SiGe NCs, due to lattice vibration and to contribution of non-radiative recombination at low temperatures.

    关键词: TiO2,magnetron sputtering,nanocrystals,photoconductivity,SiGe,annealing

    更新于2025-09-23 15:22:29