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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
  • charge – discharge energy efficiency
  • Lithium-ion battery
  • degradation diagnosis
  • photovoltaic surplus energy
  • working electric vehicle
应用领域
  • Electrical Engineering and Automation
机构单位
  • Ritsumeikan University
493 条数据
?? 中文（中国） ▾

  • Synthesis of TiO2/SiO2-B2O3 Ternary Nanocomposites: Influence of Interfacial Properties on their Photocatalytic Activities with High Resolution Mass Spectrometry Monitoring

    摘要： An investigation on unusual interface properties of unprecedented ternary composites, formed by the inclusion of assorted proportions of B2O3 into TiO2/SiO2 structure, is conducted herein. The influences of B2O3 content and calcination temperature were evaluated. The precursor TiO2/SiO2 material was synthesized via a simple sol-gel procedure that was followed by B2O3 inclusion via maceration and calcination. The materials were fully characterized and their photocatalytic performance to degrade the Indigo Carmine dye investigated. The material prepared with a B/Ti molar ratio of 1 and at calcination temperature of 350 °C (B1-350) showed the best performance, with a superior photocatalytic activity than that of commercial TiO2. The presence of B2O3-TiO2-SiO2 interfaces in the structure of such material was of critical importance in producing a material with these attractive features. Finally, high resolution mass spectrometry monitoring allowed for the characterization of the main degradation products formed under these conditions.

    关键词： high resolution mass spectrometry,degradation of Indigo Carmine,B2O3-TiO2-SiO2 ternary nanocomposites,photocatalytic activity,by-products characterization,structural defects

    更新于2025-09-04 15:30:14

  • Two bimetallic metal–organic frameworks capable of direct photocatalytic degradation of dyes under visible light

    摘要： Two bimetallic metal–organic frameworks (MOFs), specifically {2[LiM(TDA)2(DMF)]·NH2+(CH3)2}n (M = Co (HNU-29) or Zn (HNU-30), TDA = 2,5-thiophenedicarboxylate), were synthesized by solvothermal methods. X-ray crystal structures of the two MOFs showed them to be isostructural. Thus, in both cases, the metal secondary building units were connected by TDA2? ligands to form a 3D framework whose structure can be simplified to the twofold interpenetrated dia net. HNU-29 showed excellent photocatalytic activity for the degradation of methylene blue (MB) under visible light even without the addition of H2O2 as an electron acceptor, remaining stable even after several cycles of reuse. The MB degradation followed first-order kinetics, and the photocatalytic degradation mechanism was found to be related to the effective ligand-to-metal charge transfer within the framework.

    关键词： Photocatalysis,Methylene blue,Metal–organic frameworks,Visible light,Dye degradation

    更新于2025-09-04 15:30:14

  • Intrinsic correlation between electronic structure and degradation: from few layers to bulk black phosphorus

    摘要： Black phosphorus (BP) has received much attention due to its fascinating properties, such as a high mobility and tunable band gap which covers the band gap lacuna between graphene and transition metal dichalcogenides. However, these advantages have been overshadowed due to the fast degradation of BP in ambient conditions. To overcome this obstacle, the degradation mechanisms should be unveiled with direct observation followed by a thorough analysis. Here, we reveal two sequential degradation processes and layer-dependent degradation rates of BP under dark conditions by scanning Kelvin probe microscopy (SKPM) measurements and theoretical modeling. The layer-dependent degradation is successfully interpreted with the oxidation model based on the Marcus-Gerischer theory (MGT). Under dark conditions, the electron transfer rate from BP to oxygen molecule depends on the number of layers that give different carrier concentrations. The oxidation rate is strongly dependent on the number of layers, and thus carrier concentrations. This suggests the possibility of stability improvement by carrier modulation. This work not only provides a deeper understanding of the degradation mechanism itself but also suggest new strategies for stable BP-based electronics design.

    关键词： oxidation model,degradation,work function,Marcus-Gerischer theory,black phosphorus

    更新于2025-09-04 15:30:14

  • Local chemical environment in hexane-methylethylketone solutions as a model of polyethylene degradation investigated by fluorescence spectroscopy

    摘要： The fluorescence spectra of pyrene and Prodan in hexane-methylethylketone solutions, which are models of polyethylene degradation, were investigated to develop a method for understanding the degradation of polymer materials. The fluorescence properties of pyrene and Prodan were highly sensitive to the polarity of the solutions. The fluorescence intensity ratios, I384/I373 for pyrene and I380/I420 for Prodan, were useful indexes for investigating the local chemical environment. These fluorescence indexes may be more than 10 times sensitive to the conventional carbonyl index by infrared absorption. This fluorescence probe method will find further application in the evaluation of polymer degradation.

    关键词： Fluorescence,Polymer degradation,Local chemical environment,Prodan

    更新于2025-09-04 15:30:14

  • Revision of the Sun’s Spectral Irradiance as Measured by SORCE SIM

    摘要： The Spectral Irradiance Monitor (SIM) instrument on board the Solar Radiation and Climate Experiment (SORCE) performs daily measurements of the solar spectral irradiance (SSI) from 200 to 2400 nm. Both temporal and spectral corrections for instrument degradation have been built on physical models based on comparison of two independent channels with different solar exposure. The present study derives a novel correction for SIM degradation using the total solar irradiance (TSI) measurements from the Total Irradiance Monitor (TIM) on SORCE. The correction is applied to SIM SSI data from September 2004 to October 2012 over the wavelength range from 205 nm to 2300 nm. The change in corrected, integrated SSI agrees within 0.1 W m?2 (1σ ) with SORCE TIM TSI and independently shows agreement with the SATIRE-S and NRLSSI2 solar models within measurement uncertainties.

    关键词： Solar spectral irradiance,Degradation correction,Solar spectrum,Solar variability,Solar cycle

    更新于2025-09-04 15:30:14

  • Generating highly specific spectra and identifying thermal decomposition products via Gas Chromatography / Vacuum Ultraviolet Spectroscopy (GC/VUV): Application to nitrate ester explosives

    摘要： Gas chromatography/mass spectrometry (GC/MS) is a "workhorse" instrument for chemical analysis, but it can be limited in its ability to differentiate structurally similar compounds. The coupling of GC to vacuum ultraviolet (VUV) spectroscopy is a recently developed technique with the potential for increased detection specificity. To date, GC/VUV has been demonstrated in the analysis of volatile organic compounds, petroleum products, aroma compounds, pharmaceuticals, illegal drugs, and lipids. This paper is the first to report on the utility of GC/VUV for explosives analysis in general, and the first to report on thermal degradation within the VUV cell and its analytical utility. The general figures of merit and performance of GC/VUV were evaluated with authentic standards of nitrate ester explosives (e.g., nitroglycerine (NG), ethylene glycol dinitrate (EGDN), pentaerythritol tetranitrate (PETN), and erythritol tetranitrate (ETN)). In addition, the explosive analytes were thermally degraded in the VUV cell, yielding reproducible, complex and characteristic mixtures of gas phase products (e.g., nitric oxide, carbon monoxide, and formaldehyde). The relative amounts of the degradation products were estimated via spectral subtraction of library spectra. Lastly, GC/VUV was used to analyze milligram quantities of intact and burned samples of double-base smokeless powders containing nitroglycerine, diphenylamine, ethyl centralite, and dibutylphthalate.

    关键词： Thermal degradation,Nitrate ester explosives,Vacuum ultraviolet spectroscopy,Gas chromatography

    更新于2025-09-04 15:30:14

  • Advanced oxidation of formaldehyde in aqueous solution using the chemical-less UVC/VUV process: Kinetics and mechanism evaluation

    摘要： This study was conducted to evaluate the degradation of high concentrations of formaldehyde in the chemical-less UVC/VUV photo-reactor. 99.5% degradation and 94% chemical oxygen demand (COD) removal of 200 mg/L formaldehyde was achieved in the UVC/VUV photo-reactor at reaction time of 60 min and solution pH of 7. The effect of water anions such as carbonate, bicarbonate, nitrate, chloride, sulfate and phosphate was examined on degradation and COD removal of formaldehyde; nitrate and carbonate exhibited the highest inhibitory effects on the process. Besides, treatment of formaldehyde-contaminated tap water was also investigated and formaldehyde removal was decreased from 99.5% is aqueous solution to 86.2% in tap water. The findings of radical scavenging tests revealed that hydroxyl radical was the most predominant oxidizing agent contributed in degradation of formaldehyde. It is concluded therefore that the UVC/VUV process as a unique chemical-less process efficient for advanced degradation of high concentrations of formaldehyde.

    关键词： Hydroxyl radical,COD removal,Vacuum UV,Formaldehyde degradation,Advanced photo-oxidation

    更新于2025-09-04 15:30:14

  • Facile <i>Justicia adhatoda</i> leaf extract derived route to silver nanoparticle: Synthesis, characterization and its application in photocatalytic and anticancer activity

    摘要： The aim of the present study is to investigate the photocatalytic and anticancer activity of green synthesized silver nanoparticle (AgNPs) using leaf extract of Justicia adhatoda. Several techniques were used to confirm and characterize the synthesized AgNPs. The synthesis of nanoparticle was identified by the formation of dark brown color in the reaction mixture and SPR band noted at 425 nm. The obtained AgNPs were spherical in shape with its average sizes in the ranges of 12.0, 26.7 and 47.9 nm, respectively, it can be tuned by varying the concentration of AgNO3 analyzed by High resolution Scanning Electron Microscope and Transmission Electron Microscope (HRSEM with EDAX and TEM). The formation and size distribution of obtained AgNPs were determined by Dynamic Light Scattering (DLS) method. The negative zeta potential values were observed, causing dispersion stability of synthesized AgNPs. Fourier transform infrared spectroscopy (FTIR) and Surface Enhanced Raman (SERS) analyzed the existence of alcohols, amides and etc., in the leaf extract which behave as capping and reducing agents for the synthesis. The Face Centered Cubic (FCC) nature of AgNPs was depicted by X-Ray Diffraction analysis. The photocatalytic activity is established by size-dependent nature of AgNPs, using an organic dye (methylene blue) as a substrate. Besides, the AgNPs showed significant anticancer activity against Human lung cancer cell line (A549). From in-vitro investigation and dye degradation experimental studies confirmed that the synthesized AgNPs have potent photocatalytic as well as anticancer activity.

    关键词： anticancer,photocatalytic degradation,J.adhatoda,AgNPs,Green synthesis

    更新于2025-09-04 15:30:14

  • Synthesis g-C <sub/>3</sub> N <sub/>4</sub> of high specific surface area by precursor pretreatment strategy with SBA-15 as a template and their photocatalytic activity toward degradation of rhodamine B

    摘要： Using SBA-15 as a template, high surface area porous graphitic carbon nitrides (g-C3N4) were successfully synthesized by pretreating melamine using hydrochloric acid, and fully characterized by Fourier-Transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron micrographs (SEM), N2 adsorption-desorption, ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence (PL) spectrum. The results of these analyses indicated that the g-C3N4 synthesized from HCl-pretreated melamine with SBA-15 as a template has enhanced specific surface area and increased the separation rate of the photogenerated electrons and holes compared with bulk g-C3N4, but didn’t change the structure of bulk g-C3N4. The photocatalytic activity of samples was evaluated by the degradation of rhodamine B (RhB) under xenon lamp. The results indicated that the activity was improved significantly with the increase of specific surface area. The rate constant for CN-3（ HCl pretreatment melamine precursor and SBA-15 as a template） was 13 times as high as g-C3N4. Furthermore, the CN-3 catalyst exhibited outstanding structural and catalytic stability.

    关键词： precursor pretreatment strategy,SBA-15 template,g-C3N4,Degradation of RhB,high surface area

    更新于2025-09-04 15:30:14

  • Visible–light driven photocatalytic degradation of bisphenol-A using ultrasonically synthesized polypyrrole/K-birnessite nanohybrids: Experimental and DFT studies

    摘要： Although manganese oxides are known for their semiconductor characteristics, the photocatalytic performance of conducting polymer intercalated K-Birnessite (K-Bi) has not been explored till date. With the view to design a visible light driven organic–inorganic hybrid photocatalyst for rapid degradation of Bisphenol A (BPA), the present work reports the ultrasound-assisted green synthesis of K-Bi/polypyrrole (Ppy) nanohybrids. The loading of Ppy in K-Bi was confirmed by thermogravimetric analysis while the formation of organic–inorganic hybrid was confirmed by infrared spectroscopy. K-Bi revealed a band gap of 2.8 eV while for the nanohybrids it was found to be ranging between 2.4 and 1.6 eV. X-ray diffraction studies confirmed partial intercalation of Ppy chains in the inter-layer space of K-Bi. High resolution transmission electron microscopy and scanning electron microscopy studies showed mixed morphology of K-Birnessite/Ppy nanohybrids. Rapid degradation of BPA was observed under visible irradiation in presence of K-Bi/Ppy nanohybrids and almost 90% degradation of 20 mg/L BPA solution was achieved within 120 min. The degradation was found to follow pseudo-first order kinetics and the degraded fragments were identified using liquid chromatography-mass spectrometry. Degradation pathway was proposed based on density-functional theory calculations of fukui index predicting the radical easy-attacking (f0) and (f-) sites in BPA.

    关键词： DFT calculations,Degradation kinetics,Photocatalysis,Manganese oxide,Polypyrrole

    更新于2025-09-04 15:30:14