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oe1(光电查) - 科学论文

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出版时间
  • 2018
研究主题
  • imgae sensor
  • internet of things
  • drone
  • visible light ID
  • Signal-to-Noise Ratio (SNR)
  • Infinite Gain Multiple Feedback (IGMF)
  • Visible Light Communications (VLC)
  • LED
  • Trans-Impedance Amplifier (TIA)
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • Tohoku University
  • University of Northumbria
  • University of Huddersfield
645 条数据
?? 中文（中国） ▾

  • Photocatalytic Degradation of Reactive Dyes Over Titanates

    摘要： MTiO3 (M = Sr, Ca, Ba and Pb) catalysts were synthesized by polymeric precursor method and characterized by using various instrumental techniques such as X-ray diffraction (XRD), UV-diffuse reflectance spectroscopy (UV-DRS), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). TiO2 were also synthesized by sol–gel method and used for the optimization of reaction parameters such as catalyst weight, dye concentration and pH in the photocatalytic degradation of reactive dyes such as reactive blue 198 (RB 198), reactive black 5 (RB 5) and reactive yellow 145 (RY 145) under UV irradiation. MTiO3 (M = Sr, Ca, Ba and Pb) catalysts were evaluated towards the photocatalytic decolourization of RB 198, RB 5 and RY 145 under optimized reaction conditions. Among the different metal titanates, strontium titanate showed the highest decolourization (≈90%) of all the three reactive dyes under UV irradiation at 120 minutes and also found to be active under visible irradiation as it decolourises the dyes in about 450 minutes. The degradation rate of strontium titanate was monitored by TOC analyzer. Kinetic studies of the photocatalytic degradation of reactive dyes confirmed that the reaction followed the pseudo first order kinetics.

    关键词： Perovskites,Reactive Dyes,Polymeric Precursor,UV-Visible Degradation,Sol–Gel

    更新于2025-09-04 15:30:14

  • SPECTROSCOPIC STUDIES ON POUZOLZIA WIGHTII BENN

    摘要： Objective: The present study was aimed to reveal the spectroscopic profile (UV-Vis and FT-IR) of Pouzolzia wightii Benn. Methods: To detect the UV-Vis spectroscopic profile of P. wightii crude extracts were examined under UV-Vis Shimadzu spectrophotometer with the wavelength ranged from 100 to 1100 nm. About 1 mg of different extracts of petroleum ether, chloroform, ethyl acetate and acetone, ethanolic extracts of P. wightii were separately made into thin discs with 10-100 mg of potassium bromide using a mould and pressed under anhydrous conditions. The pellets were measured in an automatic recording FT-IR Spectrophotometer (Shimadzu 8400S) in the range of 400 to 4000 cm-1 Results: In UV-Vis analysis, P. wightii petroleum ether extracts showed more number of peaks in roots (15) than other studied parts. Chloroform and ethyl acetate extracts of P. wightii leaves observed 9 peaks and acetone extracts of P. wightii stem showed 10 peaks. Medicinal property of plant extracts are confirmed by the presence of secondary metabolites. FT-IR analysis of ethyl acetate extracts of P. wightii leaves, stem and root observed the highest number of (16, 12 and 16) functional compounds. Conclusion: These UV-Vis and FT-IR spectroscopic results may be used as a pharmacognostic marker in the pharmaceutical industries and can be used as a chemometric tool to distinguish the studied P. wightii leaves, stem and root. The present study used to find out the bioactive compounds which may be subjected to subsequent target isolation. Further research will be needed for the structural characterization of the isolated compound by the use of different analytical methods such as NMR and mass spectrophotometer.

    关键词： Pharmacognosy,FT-IR-Fourier Transform-Infra Red,Pouzolzia wightii,UV-Vis-Ultra Violet–Visible

    更新于2025-09-04 15:30:14

  • Synthesis of Al-MCM-41@Ag/TiO <sub/>2</sub> Nanocomposite and Its Photocatalytic Activity for Degradation of Dibenzothiophene

    摘要： Mesoporous Al-MCM-41@Ag/TiO2 nanocomposites were synthesized successfully by combining the sol-gel method and hydrothermal treatment, using titanium isopropoxide (TTIP), AgNO3, and Vietnamese bentonite as precursors of Ti, Ag, and Si, respectively. The synthesized materials were well characterized by X-ray powder di?raction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption isotherm measurements, energy dispersive X-ray spectroscopy (EDX), UV-visible di?use re?ectance spectroscopy (UV-Vis/DRS), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity was evaluated by the photodegradation of dibenzothiophene (DBT) under both UV and visible light irradiation. MCM-41@Ag/TiO2 catalyst exhibited high catalytic activity for the oxidative desulfurization (ODS) of DBT reaching almost 100% conversions at 50°C after 2 h under UV and visible light irradiations. The signi?cant enhanced degradation of DBT over Al-MCM-41@Ag/TiO2 might be due to the synergy e?ects of high surface area of MCM-41, well-distributed TiO2 anatase, and reduced electron-hole recombination rates due to the dispersion of Ag nanoparticles.

    关键词： photocatalytic activity,Al-MCM-41@Ag/TiO2,dibenzothiophene,visible light irradiation,oxidative desulfurization

    更新于2025-09-04 15:30:14

  • mpg-C <sub/>3</sub> N <sub/>4</sub> /Ag <sub/>2</sub> O Nanocomposites Photocatalysts with Enhanced Visible-Light Photocatalytic Performance

    摘要： To study the photocatalytic activity under visible light irradiation, a series of mesoporous graphitic carbon nitride (mpg-C3N4)/Ag2O photocatalysts were synthesized. The as-prepared photocatalysts were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption Brunauer-Emmett-Teller method (N2-BET), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectra (DRS), and photoluminescence spectra (PL) methods to determine their phase structure, purity, morphology, spectroscopic and photoluminescence emission performance, respectively. Photocatalytic degradation of methyl orange (MO) aqueous solution under visible-light irradiation indicated that the mpg-C3N4/Ag2O-50 nanocomposite exhibited the best activity. The degradation rate of MO reached to 90.8% in 120 min onto the mpg-C3N4/Ag2O-50 nanocomposite, and as compared with the pure mpg-C3N4 and Ag2O samples, the photocatalytic activity of the mpg-C3N4/Ag2O-50 nanocomposite was greatly enhanced. The enhancement of photocatalytic activity was mainly ascribed to the enhanced visible-light absorption ability and the formation of p–n heterojunctions between counterparts of the nanocomposites, which promoted the generation and separation of charge carriers.

    关键词： mpg-C3N4/Ag2O,MO Degradation,Photocatalytic Activity,Visible-Light Photocatalysis,p–n Heterojunctions

    更新于2025-09-04 15:30:14

  • Preparation of Nano Spinel Doped TiO <sub/>2</sub> and Its Photocatalytic Activity Evaluation Under Visible Light Irradiation

    摘要： Nano MgFe–TiO2 photocatalyst was prepared by mixing nanoscale spinel compounds such as magnesium ferrite (MgFe) and TiO2. The cations produced by MgFe are affected by various influencing factors such as calcination temperature, precursor, and mass ratio of Mg and Fe. This study is to evaluate the photocatalytic efficiency of nano MgFe-doped TiO2 under visible light according to the composition ratio of Mg, Fe and TiO2. With an increase the percentage of doping (i.e., Mg and Fe) over TiO2, the band gap between conduction band and valance band decreases, therefore showing better photocatalytic activity in visible light. Also as percentage of doping over TiO2 increases, surface area of the catalyst also increases subsequently resulting in an increase in the adsorption capacity.

    关键词： Visible Light,Spinel Compound,Magnesium Ferrite,Photocatalysis,TiO2

    更新于2025-09-04 15:30:14

  • A Facile Method for Preparation of Cu2O-TiO2 NTA Heterojunction with Visible-Photocatalytic Activity

    摘要： Based on highly ordered TiO2 nanotube arrays (NTAs), we successfully fabricated the Cu2O-TiO2 NTA heterojunction by a simple thermal decomposition process for the first time. The anodic TiO2 NTAs were functioned as both “nano-container” and “nano-reactors” to load and synthesize the narrow band Cu2O nanoparticles. The loaded Cu2O expanded absorption spectrum of the TiO2 NTAs from ultraviolent range to visible light range. We found that the Cu2O-TiO2 NTA heterojunction films had visible activity towards photocatalytic degrading methyl orange (MO). The photocatalytic abilities of the Cu2O-TiO2 NTA heterojunction films were found increased with the Cu2O content from 0.05 to 0.3 mol/L. This could be explained by more electron-hole pairs generated and less recombination, when the Cu2O-TiO2 heterojunction got formed. Here, we put forward this promising method, hoping it can facilitate the mass production and applications of Cu2O-TiO2 NTA heterojunction.

    关键词： TiO2 nanotube,Visible photocatalysis,Thermal decomposition,Cu2O,Heterojunction

    更新于2025-09-04 15:30:14

  • Preparation of erythromycin imprinted polymer by metal-free visible-light–induced ATRP and its application in sensor

    摘要： Erythromycin (ERY) molecular imprinted polymer was prepared on the surface of Au electrode modified with Ni and Au nanoclusters (MIP/AuNCs/Ni/Au) via metal-free visible-light–induced atom transfer radical polymerization, which was very easy, controllable, and environmentally benign. MIP/AuNCs/Ni/Au was examined by energy dispersive spectrometer (EDS), scanning electron microscope (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Further, MIP/AuNCs/Ni/Au was successfully used for the determination of ERY by differential pulse voltammetry (DPV). Under the optimal conditions, MIP/AuNCs/Ni/Au gave a linear correlation over the ERY concentration from 1.0 × 10?8 to 1.0 × 10?1 mg/L with the detection limit of 3.2 × 10?9 mg/L (S/N = 3). Comparing with the similar sensors, the larger linear range and lower detection limit indicated the promising prospect of this electrochemical sensor. Hence, this study was of great importance for the polymer-modified electrodes and the sensitive detection of ERY.

    关键词： Molecular imprinted polymer (MIP),Metal-free visible-light–induced atom transfer radical polymerization (MVL ATRP),Erythromycin (ERY)

    更新于2025-09-04 15:30:14

  • Photocatalytic C(sp3)-H activation towards α-methylenation of ketones using MeOH as 1C source steering reagent

    摘要： Unprecedented direct access to terminal enones via α-methylenation of aryl ketones to form C=C bond is achieved under visible-light conditions using methanol as one carbon source substrate and solvent as well. The reaction involves Cu@g-C3N4-catalysed in situ oxidation of methanol into formaldehyde followed by dehydrative cross aldol type reaction. Various aryl ketones react efficiently with MeOH, producing α,β-unsaturated carbonyl compounds only in 4-8 h at room temperature in excellent yield (84-97%). Operational simplicity, wide substrate scope, ambient reaction conditions, visible-light photocatalysis and novel application of MeOH as methylene donor substrate are the salient features making the envisaged protocol mild, efficient and green alternative to the existing methods for synthesis of such fine chemicals.

    关键词： g-C3N4,1 C source,Ketone,Visible-light,Terminal enone

    更新于2025-09-04 15:30:14

  • Preparation of size-controlled silver phosphate catalysts and their enhanced photocatalysis performance via synergetic effect with MWCNTs and PANI

    摘要： In this work, novel photocatalysts Ag3PO4@MWCNTs@PANI with excellent visible light photocatalytic performance and photostability were successfully prepared by a facile in-situ precipitation method. The optimal catalyst Ag3PO4@0.1%MWCNTs@3%PANI showed the highest photocatalytic performance for degradation of phenol and p-nitrophenol, the apparent rate constant of which was 21.9 and 10 times than that of the pure Ag3PO4, respectively. Interestingly, the Ag3PO4 exhibited significant changes in particle size, which changed from 10-20 μm for pure Ag3PO4 particles into 0.38-1.0 μm and 0.15-0.38 μm with the addition of MWCNTs and PANI, respectively. In presence of MWCNTs, similar phenomena have been reported in our previous studies, while the ability of PANI dissolved in the presence of DMF solvent to control the size of Ag3PO4 crystal was reported for the first time. The dramatic enhancement of photocatalytic activity and photostability could be attributed to the synergetic effect between MWCNTs and PANI on Ag3PO4. The MWCNTs penetrating in the bulk phase of Ag3PO4 could serve as conductors of photogenerated electrons and rapidly migrated electrons to the surface of the photocatalysts. Meanwhile, photogenerated holes in the valence band of Ag3PO4 were transferred to the photocatalysts surface through HOMO of PANI. Consequently, high separation efficiency of electron-hole pairs was successfully achieved. A novel design and preparation strategy for photocatalyst was proposed to simultaneously achieve the small size control of catalyst crystal and improve the photocatalytic performance of catalyst by adding MWCNT and PANI.

    关键词： MWCNTs,PANI,size-controlled,visible light catalyst,photocatalysis

    更新于2025-09-04 15:30:14

  • BixTiyOz-Fe multiphase systems with excellent photocatalytic performance in the visible

    摘要： New photocatalysts based on bismuth titanates doped with iron with outstanding visible photocatalytic activity were prepared by a facile hydrothermal method followed by incipient wetness impregnation. The starting material was composed by three phases; majority of Bi20TiO32 closely interconnected to Bi4Ti3O12 and amorphous TiO2. Fe doping increased the already very high visible activity of the original material. The high visible activity showed by these materials could be ascribed to a combination of several features; i.e. low band gap energy value (as low as 1.78 eV), a structure allowing a good separation path for visible photogenerated electron-holes pairs and a relatively high surface area. Fe doping could be acting as bonding paths for the bismuth titanates phases, and the amount of Fe on the surface was found to be a crucial parameter on the photocatalytic activity of the materials. Visible activity of the best photocatalyst was superior to UV-Activity of commercial TiO2 P25 used as reference in same experimental conditions.

    关键词： Fe doping,Bi20TiO32,Bi4Ti3O12,Visible photocatalysis,Phenol degradation

    更新于2025-09-04 15:30:14