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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） ▾

  • A comparison of water photo-oxidation and photo-reduction using photoelectrodes surface-modified by deposition of co-catalysts: Insights from photo-electrochemical impedance spectroscopy

    摘要： The purpose of this research paper is to highlight the similarities in the kinetic treatment between water photo-oxidation into molecular oxygen and water photo-reduction into molecular hydrogen, using photoelectrodes surface modified by deposition of co-catalysts. Photo-anodes made of TiO2 nanorods surface-covered by crystals of cobalt Zeolitic Imidazolate Framework (ZIF-67), and photo-cathodes made of Rh:SrTiO3 particles surface-modified by adsorption of molecules of trisdioximate hexa-chlorine cobalt (II) clathrochelate (Co(Cl2Gm)3(BCH3)2), have been prepared and used for water photo-oxidation and photo-reduction experiments, respectively. Both photoelectrodes have been characterized by SEM and cyclic voltammetry under illumination conditions. Charge transfer mechanisms have been investigated by photo-electrochemical impedance spectroscopy (PEIS). It is shown that for both systems, the presence of a co-catalyst increases the charge transfer kinetics, and that the trapping resistance is larger than the charge transfer resistance, at any operating potential.

    关键词： Water photo-oxidation,Titanium dioxide nanorods,Strontium titanate,Water photo-reduction,ZIF-67 MOF

    更新于2025-09-23 15:23:52

  • A new insight for photocatalytic hydrogen production by a Cu/Ni based cyanide bridged polymer as a co-catalyst on titania support in glycerol water mixture

    摘要： A two dimensional Cu/Ni based coordination polymer (CP-1) $0.7(C2H6O2)$1.6(H2O) (4,4?-dipy ? 1,3-di(4-pyridyl)propane) has been demonstrated as a potential co-catalyst on TiO2 support for hydrogen evolution under UV light. CP-1/TiO2 composite exhibits considerable hydrogen production in comparison with the pristine CP-1 and TiO2 (P25), highlighting that the photocatalytic performance is significantly related with the good separation of photo generated e-/h+ pairs. Different wt. % (2.5, 5 and 7.5%) of CP-1 in CP-1/TiO2 composites were tested for photocatalytic hydrogen production in 5 vol % glycerol/water mixture. The 5 wt % CP-1/TiO2 composite displayed the greatest hydrogen production of 9.2 mmol h-1 g-1. The concealed mechanism is divulged on the behalf of results obtained by cyclic voltammetry, photoluminescence and diffused reflectance/UV-visible studies which demonstrate that upon irradiation of UV light, electrons transfer from TiO2 conduction band to CP-1. CP-1 not only grabs the conduction band electrons of titania but also performes as a co-catalyst to reduce the protons into hydrogen. These results are anticipated to direct the forthcoming advancement in creating proficient, cheap semiconductor photocatalysts for solar hydrogen production.

    关键词： Hydrogen,Coordination polymer,Co-catalyst,Photocatalyst,Titanium dioxide

    更新于2025-09-23 15:23:52

  • Comparing the Efficiency of N-Doped TiO2 and N-Doped Bi2MoO6 Photo Catalysts for MB and Lignin Photodegradation

    摘要： In this study, we tested the efficiency of nitrogen-doped titanium dioxide (N-TiO2) and nitrogen-doped bismuth molybdate (N-Bi2MoO6) compounds as photocatalysts capable of degrading methylene blue and lignin molecules under irradiation with ultraviolet (UV) and visible light (VIS). Moreover, we compared TiO2 and Bi2MoO6 catalysts with N-TiO2 and N-Bi2MoO6 compounds using chemical coprecipitation. The catalysts were prepared starting from Ti(OCH2CH2CH3)4, Bi(NO3)3·5H2O, and (NH4)6Mo7O24 reagents. N-doping was achieved in a continuous reflux system, using ethylene diamine as a nitrogen source. The resulting materials were characterized using Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Additionally, we observed the decrease in particle size after processing the compounds in the reflux system. The results regarding photocatalytic degradation tests show a remarkable effect for nitrogen doped samples, achieving 90% of lignin degradation.

    关键词： photocatalysis,lignin,visible light,UV light,bismuth molybdate,Titanium dioxide

    更新于2025-09-23 15:23:52

  • Optimizing one-dimensional TiO2 for photocatalytic hydrogen production from a water-ethanol mixture and other electron donors

    摘要： This work is focused on synthesizing and employing one-dimensional (1D) titanium dioxide (TiO2) for hydrogen (H2) production. Based on using electron donors (EDs) (ethanol, methanol, formic acid and 1,2,3 propanetriol), the increased H2 production, when compared to P25 TiO2 nanoparticles, was due to the large specific surface area (SSA) and enhanced electron mobility of 1D TiO2. The impact of the 1D TiO2 synthesis reaction conditions (temperature, NaOH concentration and the TiO2 precursor concentration) on the photocatalytic H2 production rate was evaluated using a 3-factor 3-level Box Behnken design (BBD). The BBD model demonstrated that the temperature and the NaOH concentration significantly affected the 1D TiO2 phase structure, crystal size, SSA, bandgap and the photocatalytic H2 production rate. The phase structure and crystal size of 1D TiO2 were key factors affecting the H2 production rate. 1D TiO2 containing an anatase phase with a mean crystal size of 20.1±0.2 nm was synthesized at 126oC, 15 M NaOH and 49 g·L-1 TiO2. The maximum H2 production rate of 475±12 μmol·h-1 (quantum efficiency (ε) = 20.2±0.5%) for the 1D TiO2 sample was significantly enhanced when compared to commercial TiO2 P25. The H2 production rate for the optimized 1D TiO2 was significantly enhanced by decorating the structure with Pt and Au. Hydrothermal synthesized of 1D TiO2 provided an efficient and low cost method for producing H2 from ethanol, methanol, formic acid and 1,2,3 propanetriol.

    关键词： hydrogen production,hydrothermal,1D titanium dioxide,TiO2-B,anatase,photocatalyst,quantum yield

    更新于2025-09-23 15:23:52

  • Surface functionalization of titanium with zinc/strontium-doped titanium dioxide microporous coating via microarc oxidation

    摘要： Deficient osseointegration and implant-related infections are pivotal issues for the long-term clinical success of titanium (Ti) implants. Zinc (Zn) and strontium (Sr) serve dual functions by promoting osteogenesis and inhibiting bone destruction, and Zn has good antibacterial activity. As such, this study examined the preparation of a Zn/Sr-doped titanium dioxide microporous coating (MT-Zn/Sr) on a Ti surface using microarc oxidation (MAO), with Zn and Sr evenly distributed throughout the coating. In vitro, the coating could promote the adhesion, proliferation, differentiation and mineralization of osteoblasts, showing good biological activity. Antibacterial testing demonstrated the good antibacterial activity of the coating, as it inhibited the proliferation of Staphylococcus. In vivo, MT-Zn/Sr promoted early osseointegration between the Ti substrate and the bone tissue. This work is expected to provide a new method for improving the biological activity of Ti implants and thus has important theoretical significance and great clinical prospects.

    关键词： Osseointegration,Strontium,Zinc,Titanium coating,Antibacterial property

    更新于2025-09-23 15:23:52

  • Metal–organic framework coated titanium dioxide nanorod array p–n heterojunction photoanode for solar water-splitting

    摘要： This paper presents a p–n heterojunction photoanode based on a p-type porphyrin metal–organic framework (MOF) thin film and an n-type rutile titanium dioxide nanorod array for photoelectrochemical water splitting. The TiO2@MOF core–shell nanorod array is formed by coating an 8 nm thick MOF layer on a vertically aligned TiO2 nanorod array scaffold via a layer-by-layer self-assembly method. This vertically aligned core–shell nanorod array enables a long optical path length but a short path length for extraction of photogenerated minority charge carriers (holes) from TiO2 to the electrolyte. A p–n junction is formed between TiO2 and MOF, which improves the extraction of photogenerated electrons and holes out of the TiO2 nanorods. In addition, the MOF coating significantly improves the efficiency of charge injection at the photoanode/electrolyte interface. Introduction of Co(III) into the MOF layer further enhances the charge extraction in the photoanode and improves the charge injection efficiency. As a result, the photoelectrochemical cell with the TiO2@Co-MOF nanorod array photoanode exhibits a photocurrent density of 2.93 mA/cm2 at 1.23 V (vs. RHE), which is ~ 2.7 times the photocurrent achieved with bare TiO2 nanorod array under irradiation of an unfiltered 300 W Xe lamp with an output power density of 100 mW/cm2.

    关键词： p–n junction,photoanode,titanium dioxide,metal-organic framework,water-splitting

    更新于2025-09-23 15:23:52

  • Application of quantitative light-induced fluorescence technology for tooth bleaching treatment and its assessment: An in vitro study

    摘要： Objectives: This study aimed to determine the effectiveness of combination of photocatalysts - low concentration of hydrogen peroxide (3.5%) and titanium dioxide (TiO2), activated at a wavelength of 405 nm using quantitative light-induced fluorescence (QLF) technology, and to quantify the tooth-bleaching effect using fluorescence images from QLF technology. Materials and Methods: Forty bovine incisors were extrinsically stained according to Stookey’s method. Two bleaching solutions were prepared by mixing 3.5% H2O2 with 0.05% of anatase and rutile nano-TiO2 powder. These solutions were applied to the stained teeth using a micro-brush and then irradiated for 15 minutes at either 306 or 405 nm to activate the bleaching agent. The color difference was assessed before and after every 5 minutes of treatment. The ?E and ?F were obtained from white-light and fluorescence images, respectively. Results: All the low H2O2/TiO2 treatments caused significant bleaching after irradiation at 306 and 405 nm (p<0.05). There was no significant difference between the wavelengths (p>0.05), but a greater bleaching effect was obtained with anatase-TiO2 at 306 nm and rutile-TiO2 at 405 nm. Analysis of the fluorescence images revealed that the ?F values decreased significantly in all the groups according to the treatment times (p<0.05). There was a statistically significant reverse correlation between ?E and ??F (r= -0.822, p<0.001). Conclusions: Low H2O2/TiO2 with 405 nm of QLF technology demonstrated greater bleaching effect. Furthermore, the fluorescent images from QLF technology showed a possibility for assessment of tooth bleaching.

    关键词： Digital imaging,Tooth bleaching,Theragnosis,405 nm wavelength,Titanium dioxide,Quantitative light-induced fluorescence (QLF)

    更新于2025-09-23 15:23:52

  • Electrostatically Directed Assembly of Nanostructured Composites for Enhanced Photocatalysis

    摘要： It is well established that the activity of photocatalysts can be improved by deposition of redox catalysts, which can effectively extract the photogenerated charge carriers, enhance the rate of interfacial reactions, and thus suppress undesired recombination processes. For optimum performance, a high degree of control over the loading, size, and surface catalytic properties of redox catalyst particles is desirable. Herein, a novel, highly controllable, and versatile method for preparation of TiO2 catalyst composites is reported. It starts with the generation of “naked” (ligand-free) nanoparticles of CuOx or FeOx by pulsed laser ablation of metal oxide targets in water. In the next step, a nearly quantitative colloidal deposition of CuOx and FeOx nanoparticles onto anatase TiO2 substrate is achieved by adjusting the pH in order to establish electrostatic attraction between the colloids and the substrate. The resulting TiO2–CuOx and TiO2–FeOx assemblies with optimum catalyst amount (≈0.5 wt%) exhibit photocatalytic rates in degradation of 2,4-dichlorophenoxyacetic acid enhanced by a factor of ≈1.5 as compared to pristine TiO2 under simulated solar irradiation. The electrostatically directed assembly of TiO2 with ligand-free catalyst nanoparticles generated by pulsed laser ablation is thus demonstrated as a viable tool for preparation of composites with enhanced photocatalytic performance.

    关键词： photocatalysis,titanium dioxide,laser ablation,colloidal deposition,nanoparticles

    更新于2025-09-23 15:23:52

  • UV Illumination-Enhanced Molecular Ammonia Detection Based On a Ternary-Reduced Graphene Oxide–Titanium Dioxide–Au Composite Film at Room Temperature

    摘要： In this work, we report on UV illumination enhanced room-temperature trace NH3 detection based on ternary composites of reduced graphene oxide nanosheets (rGO), titanium dioxide nanoparticles (TiO2) and Au nanoparticles as the sensing layer, which is firstly reported by far. The effect of UV state as well as componential combination and content on the sensing behavior disclosed that, rGO nanosheets served as not only a template to attach TiO2 and Au, but an effective electron collector and transporter; TiO2 nanoparticles acted as a dual UV and NH3 sensitive material; Au nanoparticles could increase the sorption sites and promote charge separation of photoinduced electron-hole pairs. The as-prepared rGO/TiO2/Au sensors were endowed with a sensing response of 8.9% toward 2 ppm NH3, a sensitivity of 1.43×10-2/ppm within the investigated range, nice selectivity, robust operation repeatability and stability, which was fairly competitive in comparison with previous work. Meanwhile, the experimental results provided clear evidence of inspiring UV-enhanced gas detection catering for the future demand of low power-consumption and high sensitivity.

    关键词： Room temperature.,Gas sensor,Reduce graphene oxide,Ammonia,Au nanoparticle,Titanium dioxide,UV illumination

    更新于2025-09-23 15:23:52

  • Fluorine modification on titanium dioxide particles: Improving the anti-icing performance through a very hydrophobic surface

    摘要： In this study, fluorine modification was successfully conducted on titanium dioxide (TiO2) to enhance the anti-icing property through fabricating a very hydrophobic surface. TiO2 was firstly modified with 3-methacryloxypropyl-trimethoxysilane (MPS) to introduce C=C bonds. Then, dodecafluoroheptyl methacrylate (DFHMA) monomers were successfully grafted on the TiO2 particles via C=C bonds introduced by MPS. Herein, azobisisobutyronitrile (AIBN) was used as initiator to initiate the reaction. The chemical components of the TiO2 particles were investigated by X-ray photoelectron spectroscopy (XPS). XPS analysis of fluorine-modified TiO2 revealed that the fluorine content reached a peak value of 7.3%, while the water contact angle enhanced to a maximum value of 146o. This water contact angle value of 146o was dramatically increased by 131o in comparison with unmodified TiO2, indicating a very hydrophobic surface. The crystallization temperature of a water droplet on the corresponding fluorine-modified TiO2 decreased to -19.4 oC (10.3 oC decrease in comparison with that of a water droplet on unmodified TiO2). Also, the freezing delay time on the fluorine-modified TiO2 is more than 25 min under the testing temperature of -10 oC, exhibiting excellent anti-icing property.

    关键词： Azobisisobutyronitrile,Fluorine modification,Anti-icing property,Dodecafluoroheptyl methacrylate,Titanium dioxide

    更新于2025-09-23 15:23:52