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oe1(光电查) - 科学论文

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出版时间
  • 2019
研究主题
  • Dye-sensitized solar cell
  • Photoelectrode
  • Light scattering layer
  • Transmittance
  • White pigment (R902+)
  • Rutile titanium dioxide
应用领域
  • Optoelectronic Information Materials and Devices
机构单位
  • Tribhuvan University
387 条数据
?? 中文（中国） ▾

  • Synthesis of a novel visible light responsive <i>γ</i> -Fe2O3/SiO2/C-TiO2 magnetic nanocomposite for water treatment

    摘要： This work investigates the preparation of a magnetically recoverable photocatalytic nanocomposite of maghemite nanoparticles coated with silica and carbon doped titanium dioxide. The novel nanocomposite boasts the advantages of efficient photocatalytic degradation of organic pollutants in water and ease of recovery of the fine particles after water treatment. The photocatalytic nanocomposite was successfully synthesized through a stepwise approach via co-precipitation and sol-gel methods. Characterisation by FTIR, XRD, TEM and EDS substantiated the existence of the intended structure of the nanocomposite and the particles were found to be in the size range of 15–22 nm with a quasi-spherical shape. BET surface area analysis revealed an average surface area of 55.20 m2/g which is higher than that of commercial TiO2 (Degussa P25, 50.00 m2/g) and an average pore diameter of 8.36 nm. A 5 ppm methylene blue solution was degraded with an efficiency of 96.8% after 3 h of solar irradiation, which was 19.7% greater than using the same photo-catalyst under strict UV light irradiation. Photo-catalysis using these nanoparticles was observed to be very effective. The prepared novel visible light active nanocomposite has great potential for incorporation into water treatment systems because it exhibits good stability and magnetism as well as high photocatalytic efficiency.

    关键词： methylene blue,titanium dioxide,water treatment,maghemite,photo-catalysis,magnetic nanocomposite

    更新于2025-09-23 15:22:29

  • The influence of Eu3+ concentration on the spectroscopic properties of YAG:Ti, Eu3+ nanocrystalline luminescent thermometer

    摘要： The influence of Eu3+ co-dopant on the luminescent properties of an yttrium aluminum garnet co-doped with titanium and europium ions (YAG: Ti, Eu) nanocrystals has been investigated. This is a continuation of the search for novel materials suitable for luminescence thermometry using an approach based on inorganic nanocrystals co-doped with transition metal ions and lanthanides. The optical response of Ti3+, Ti4+ and Eu3+ ions present in the examined structures was analyzed in a wide range of temperatures. A model of distribution of energy levels of these ions explaining the observed spectra and their dependence on the Eu concentration was proposed. Moreover, the possibility of energy transfers between these ions and their dependence on the concentration of Eu ions and on the temperature was indicated. On this basis, a model was proposed, allowing for the optimization of the maximum sensitivity and the corresponding temperature.

    关键词： Titanium,Luminescent thermometry,Europium,Eu3+,Nanocrystals

    更新于2025-09-23 15:22:29

  • Modification of graphene oxide with titanium dioxide by alcoholic reduction

    摘要： Graphene oxide (GO) nanocomposites doped with DEGUSSA (P25) was synthetized by (GO) alcoholic reduction at high temperatures, during the reduction the P25 anchored to the spaces left by carbonyls groups in the graphene network, this incorporation improved photocatalytic behavior by retarding the electro-hole pair (e? hC). Raman spectroscopy con?rms the anchorage, because the material with higher load of TiO2 presented a band at 1100 cm?1 belonging to Carbonate’s groups (CO3) and a total modi?cation of the bands D and G, also this material presents a band gap of 2.54 eV. The P25 incorporation into graphene three-dimensional arrangement is notorious in diffraction x ray patterns, because the graphene diffraction pattern shows a sharpened and smaller peak than the starting graphene oxide. The incorporation of TiO2 to graphene sheets, improved the band gap, which P25 being of 3.2 eV was reduced to almost 2.5 eV, naturally this allows it, to be an excellent material to be used as photoanodes, photovoltaic devices and photocatalysis, its demonstrated by a photodegradation of methylene blue at 60 ppm exposed to solar light and 25 ppm exposed to a sodium lamp that emits radiation close to 589 nm.

    关键词： methylene blue degradation,Band gap,graphene oxide,titanium dioxide

    更新于2025-09-23 15:22:29

  • Microstructure and mechanical properties of Ti/Al dissimilar joints produced by laser-MIG welding–brazing

    摘要： We butt-welded AA6061 aluminum alloy to Ti6Al4V titanium alloy, dissimilar light metals, by using laser-MIG hybrid welding–brazing without grooves. The parameters of the laser and arc were optimized to produce sound joints with good formation and mechanical properties. The microstructure of the layer of intermetallic compounds (IMCs) was investigated by scanning electron microscopy and energy dispersive spectroscopy. We also tested the tensile strength of the joints with and without reinforcement. The morphology and thickness of the IMCs varied throughout the joints. A continuous thin layer of TiAl3 appeared on the top surface of the Ti6Al4V, on which some rod-like IMCs grew toward the fusion zone. In the upper region of the butt plane, because more heat accumulated there from the high-power laser coupled with the MIG arc, double-layer IMCs with a thickness of ～ 10.0 μm formed, composed of TiAl (near the Ti alloy) and TiAl3 (near the fusion zone). In the lower region of the butt plane, the double-layer IMCs became continuous and uniform, the serrated morphology disappeared, and the thickness of the IMC layer decreased to 4.0 μm. On the backside of the joint, the thickness of the compound layer (TiAl3) was about 1.0 μm. The average tensile strengths of the reinforced and unreinforced joints were 226 MPa and 210 MPa, respectively, which are up to 88% and 81% of the AA6061 tensile strength, respectively.

    关键词： dissimilar joint,titanium alloy,intermetallic compounds.,Laser-MIG hybrid welding–brazing,aluminum alloy

    更新于2025-09-23 15:22:29

  • Microstructure and Characteristic of Biomedical Titanium Alloy Based on Picosecond Laser Micromachining

    摘要： Laser micromachining has become a hotspot in recent years due to its high precision, non-contact and adjustable parameter. In this paper, TC4 titanium alloy implant samples were conducted to obtain specific surface textures through picosecond laser. The laser parameters which directly influenced the microstructure and characteristic of surface textures were optimized within the context of laser power, scanning speed and scanning number via response surface methodology. The microstructure was evaluated using scanning electron microscope (SEM) while the feature size of the surface textures was measured through surface 3D profiler. In addition, endothelial cell culture was conducted to investigate the biofunctionalization of samples with specific surface textures. It demonstrated that well-structured textures played an important role in promoting cell adhesion and proliferation for titanium alloy implants.

    关键词： Picosecond laser micromachining,Microstructure,Biofunctionalization,Titanium alloy

    更新于2025-09-23 15:22:29

  • 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

  • Photocatalytic activity of anatase titanium dioxide nanostructures prepared by reactive magnetron sputtering technique

    摘要： In this work, nanostructured titanium dioxide (TiO2) photocatalysts with high optical and structural homogeneity were successfully synthesized by dc reactive magnetron sputtering technique. The TiO2 thin films were produced with high structural homogeneity without any heat treatment. Analysis of the X-ray diffraction patterns and UV–visible spectroscopy gave an indication that the structure of prepared films is anatase with energy band gap of 3.23 eV. The Fourier-transform infrared spectroscopy has confirmed the formation of Ti–O bond. The average size of TiO2 particles in the deposited films was ranging in 5–7 nm. These nanostructures are very applicable as photocatalysts as their photocatalytic activity was determined from the degradation rate with UV irradiation time as the first order reaction rate constant was determined to be 2.4 × 10?3 min?1.

    关键词： Anatase phase,Titanium dioxide,Nanostructures,Photocatalysis

    更新于2025-09-23 15:22:29

  • In-situ Platinum Plasmon Resonance Effect Prompt Titanium Dioxide Nanocube Photocatalytic Hydrogen Evolution

    摘要： In-situ photodeposition Pt nanoparticles (Pt NPs) on TiO2 on account of the surface plasmonic resonance (SPR) effect and strong interaction of two components, which exhibits an elevated solar-driven photocatalytic hydrogen evolution performance. Herein, Pt-decorated TiO2 nanocube hierarchy structure (Pt-TNCB) was in-situ fabricated via a facile solvothermal synthesis and photodeposition strategy. The Pt-TNCB exhibits an excellent solar-driven photocatalytic hydrogen evolution rate (337.84 μmol h-1), which is about 37 times higher than that of TNCB (9.19 μmol h-1). Interestingly, its photocatalytic property is still superior to TNCB with post modification Pt (1 wt %) (208.11 μmol h-1). The introduction of Pt efficiently extends the photoresponse of composite material from UV to visible light region, simultaneously boost their solar-driven photocatalytic performance, which attribute to the porous structure, the subsize TNCB, the SPR effect of Pt NPs and strong interaction of two components. In fact, Pt NPs can enhance collective oscillations on delocalized electrons, which is conducive to capture electrons and hinder the recombination of photogenerated electron-hole pairs, leading to the longer lifetime of photogenerated charges. The fabrication of Pt-TNCB photocatalyst with SPR effect may provide a promising method to improve visible-light photocatalytic activities for traditional photocatalysts.

    关键词： hydrogen evolution,titanium dioxide,surface plasmonic resonance,photodeposition,photocatalyst

    更新于2025-09-23 15:22:29

  • N-hydroxyphthalimide-TiO2 complex visible light photocatalysis

    摘要： TiO2 is the most established semiconductor photocatalyst. The prominence of TiO2 is becoming increasingly obvious because its interfacial redox reactions have implication on a wide range processes such as energy conversion and environmental remediation. Herein, we exploited the surface complex created by the interaction between organic molecules with binding sites and accommodating surface of TiO2 for visible light-driven selective aerobic oxidation reactions. A novel surface complex formed between N-hydroxyphthalimide (NHPI) and TiO2 was discovered. The NHPI-TiO2 complex turned out to be an outstanding visible light photocatalyst and was successfully used in the selective oxidation of amines into imines with atmosphere O2 under blue LED irradiation. The stability of the NHPI-TiO2 complex was preserved by 3 mol% of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) acted as a cooperative catalyst. Moreover, selectivities for the imine products were also prompted by TEMPO. Superoxide radicals (O2?-) were evidenced to be the primary reactive oxygen species (ROS) to execute the oxidative conversions. This work suggests that TiO2 surface complexes can be robust photocatalysts for visible light-driven selective aerobic reactions, provided that an appropriate cooperative redox catalyst exists to channel the photocatalytic electron transfer.

    关键词： titanium dioxide,surface complex,N-hydroxyphthalimide,molecular oxygen,TEMPO

    更新于2025-09-23 15:22:29

  • Design and Characterisation of Titanium Nitride Subarrays of Kinetic Inductance Detectors for Passive Terahertz Imaging

    摘要： We report on the investigation of titanium nitride (TiN) thin films deposited via atomic layer deposition (ALD) for microwave kinetic inductance detectors (MKID). Using our in-house ALD process, we have grown a sequence of TiN thin films (thickness 15, 30, 60 nm). The films have been characterised in terms of superconducting transition temperature Tc, sheet resistance Rs and microstructure. We have fabricated test resonator structures and characterised them at a temperature of 300 mK. At 350 GHz, we report an optical noise equivalent power NEPopt ≈ 2.3 × 10?15 W/√Hz, which is promising for passive terahertz imaging applications.

    关键词： Titanium nitride,ALD,Kinetic inductance detector

    更新于2025-09-23 15:22:29