• Title/Summary/Keyword: Photocatalytic

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Preparation and Characterization of ZnO-ACF/TiO2 Composite Catalysts for the Photocatalytic Degradation of MO under Visible Light

  • Sun, Qian;Zhu, Lei;Meng, Ze-Da;Ullah, Kefayat;Ye, Shu;Oh, Won-Chun
    • Journal of the Korean Ceramic Society
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    • v.50 no.4
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    • pp.269-274
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    • 2013
  • ACF and ZnO modified $TiO_2$ composite materials (ZnO-ACF/$TiO_2$) were prepared by a sol-gel method. The composites were characterized by X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis and scanning electron microscope (SEM) analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of the MO was determined using UV spectrophotometers. An increase in the photocatalytic activity was observed and attributed to an increase of the photo-absorption effect by the ZnO and the cooperative effect of the ACF.

Photocatalytic Degradation of Acetaldehyde and MEK using Batch Type Photo-Reactor (회분식 광촉매반응기를 이용한 아세트알데하이드와 MEK 제거특성 연구)

  • Cha, Wang Seog
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.3
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    • pp.1527-1532
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    • 2013
  • The kinetics of photocatalytic degradation of gaseous acetaldehyde and methylethylketone(MEK) were studied by the batch scale of photo-reactor. Variable parameters were initial concentration of acetaldehyde and MEK, water vapor content, and temperature. The photocatalytic degradation rate was increased with increasing concentration of acetaldehyde and MEK, but maintained gentle increase beyond a certain concentration. The Langmuir-Hinselwood model was successfully applied to correlate experimental data. Water vapor inhibited the degradation reaction of acetaldehyde and MEK. The optimum reaction temperature was $45^{\circ}C$ for acetaldehyde and MEK.

Degradation of gas-phase toluene by $TiO_2$ loaded on carbon fibers using Atomic Layer Deposition (ALD) under UV irradiation

  • Luo, Yuan;Kim, Myoung-Joo;Seo, Hyun-Ook;Kim, Kwang-Dae;Tai, Wei Sheng;Kim, Young-Dok
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.349-349
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    • 2010
  • $TiO_2$ thin films were prepared on C fibers, and photocatalytic activity of these films for removing gas-phase toluene was studied. $TiO_2$ films were deposited on C fiber with 0.5 A-per-cycle growth rate by Atomic Layer Deposition (ALD) using TTIP (titanium tetra-isopropoxide) and $H_2O$ as precursors. The catalysts were characterized by Brunauer-Emmett-Teller (BET) for surface area and Scanning Electron Microscope (SEM) for morphology, respectively. Moreover, the samples were further characterized by X-ray Photoelectron Spectroscopy (XPS). As a function of $TiO_2$ thickness, no significant change in the photocatalytic activity could be identified. Interestingly, the bare-carbon fiber showed an even higher photocatalytic activity than the $TiO_2$ thin films for removing toluene. Origin of the high photocatalytic activity of the bare C fiber is discussed.

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Photocatalytic activities and surface properties of e-beam treated carbon paper deposited $TiO_2$ using Atomic Layer Deposition (ALD)

  • Kim, Myoung-Joo;Seo, Hyun-Ook;Luo, Yuan;Kim, Kwang-Dae;Kim, Young-Dok
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.345-345
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    • 2010
  • Thin film of $TiO_2$ deposited on carbon paper was fabricated by atomic layer deposition (ALD) using titanium isopropoxide (TTIP) and $H_2O$ as precursors. In this work, the photocatalytic activities of $TiO_2$ films with and without e-beam treatment were compared. The samples were treated by e-beam using e-beam energy of 1MeV and exposure range between 5 and 15kGy. The photocatalytic activity was evaluated by the photocatalytic degradation of methyleneblue (MB) under UV irradiation (365nm) at room temperature using an UV-vis spectroscopy. The surface properties were characterized by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The sample treated by the low radiation dose has more catalytic activity than other ones. SEM images show that the high radiation dose caused the $TiO_2$ to aggregation on carbon paper. Due to the aggregation of $TiO_2$, the partially exposed carbon paper was oxidized.

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Synthesis and Characterization of Fe-fullerene/TiO2 Photocatalysts Designed for Degradation of Methylene Blue

  • Meng, Za-Da;Zhang, Kan;Oh, Won-Chun
    • Korean Journal of Metals and Materials
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    • v.48 no.7
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    • pp.674-682
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    • 2010
  • Fe-fullerene/$TiO_2$ composite photocatalysts were prepared with titanium (IV) n-butoxide (TNB) by a sol-gel method. The samples were characterized by scanning electron microscopy (SEM), Transmission electron microscope (TEM), specific surface area (BET), X-ray diffraction analysis (XRD) and energy dispersive X-ray spectroscopy (EDX). The photocatalytic activities were evaluated by the photocatalytic degradation of methylene blue (MB) solution. XRD patterns of the composites showed that the Fe-fullerene/$TiO_2$ composite contained a typical single and clear anatase phase. The surface properties shown by SEM present a characterization of the texture on Fe-fullerene/$TiO_2$ composites and showed a homogenous composition in the particles for the titanium sources used. The EDX spectra for the elemental identification showed the presence of C and Ti with strong Fe peaks for the Fe-fullerene/$TiO_2$ composite. From the photocatalytic results, the excellent activity of the Fe-fullerene/$TiO_2$ composites for degradation of methylene blue under UV light irradiation could be attributed to both the effects between photocatalytic reaction of the supported $TiO_2$, decomposition of the organometallic reaction by the Fe compound and energy transfer effects such as electron and light of the fullerene.

Synthesis of LaMnO3-Diamond Composites and Their Photocatalytic Activity in the Degradation of Weak Acid Red C-3GN

  • Huang, Hao;Lu, Benqian;Liu, Yuanyuan;Wang, Xeuqian;Hu, Jie
    • Nano
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    • v.13 no.10
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    • pp.1850121.1-1850121.11
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    • 2018
  • In this study, a series of $LaMnO_3$-diamond composites with varied $LaMnO_3$ mass contents supported on micro-diamond have been synthesized using a sol-gel method. The as-prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and the Fourier transform infrared spectra (FTIR). Meanwhile, the photocatalytic performances were also tested by photoluminescence (PL) spectroscopy, ultraviolet-visible diffuse reflection spectra (UV-Vis DRS) and the degradation of weak acid red C-3GN (RC-3GN). Results show that the peak position of $LaMnO_3$ is shifted to low angle after the introduction of diamond, and perovskite particles uniformly distributed on the surface of diamond, forming a network structure, which can increase the active sites and the absorption of dye molecules. When the mass ratio of $LaMnO_3$ and diamond is 1:2 (LMO-Dia-2), the composite shows the most excellent photocatalytic activity. This result offers a sample route to enlarge the range of the application of micro-diamond and provide a new carrier for perovskite photocatalysts.

Facile Synthesis and Characterization of GO/ZnS Nanocomposite with Highly Efficient Photocatalytic Activity

  • Li, Lingwei;Xue, Shaolin;Xie, Pei;Feng, Hange;Hou, Xin;Liu, Zhiyuan;Xu, Zhuoting;Zou, Rujia
    • Electronic Materials Letters
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    • v.14 no.6
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    • pp.739-748
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    • 2018
  • ZnS nanowalls, microspheres and rice-shaped nanoparticles have been successfully grown on graphene oxide (GO) sheets by the hydrothermal method. The morphologies, structures, chemical compositions and optical properties of the as-synthesized GO/ZnS have been characterized by X-ray power diffraction, energy dispersive spectrometer, scanning electron microscope, Raman spectra, photoluminescence spectroscopy and ultraviolet-visible absorption spectroscopy. It was found that the concentration of CTAB and the reaction temperature were important in the formation of GO/ZnS microstructures. The photocatalytic activity of the as-synthesized GO/ZnS was investigated through the photocatalytic degradation of textile dyeing waste. Results showed that the catalytic activity of the GO/ZnS porous spheres to methyl orange and methylene blue is higher than those of other samples. The degradation rates of methyl orange and methylene blue by porous spheres in 50 min were 97.6 and 97.1%, respectively. This is mainly attributed to the large specific surface area of GO/ZnS porous spheres and high separation efficiency between photogenerated electron and hole pairs.

Diameter-Controllable Synthesis and Enhanced Photocatalytic Activity of Electrospun ZnO Nanofibers (전기방사를 이용하여 제조된 산화아연 나노섬유의 직경제어 및 광촉매 특성)

  • Ji, Myeong-Jun;Yoo, Jaehyun;Lee, Young-In
    • Korean Journal of Materials Research
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    • v.29 no.2
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    • pp.79-86
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    • 2019
  • A heterogeneous photocatalytic system is attracting much interest for water and air purification because of its reusability and economical advantage. Electrospun nanofibers are also receiving immense attention for efficient photocatalysts due to their ultra-high specific surface areas and aspect ratios. In this study, ZnO nanofibers with average diameters of 71, 151 and 168 nm are successfully synthesized by facile electrospinning and a subsequent calcination process at $500^{\circ}C$ for 3 h. Their crystal structures, morphology features and optical properties are systematically characterized by X-ray diffraction, scanning electron microscopy, UV-Vis and photoluminescence spectroscopies. The photocatalytic activities of the ZnO nanofibers are evaluated by the photodegradation of a rhodamine B aqueous solution. The results reveal that the diameter of the nanofiber, controlled by changing the polymer content in the precursor solution, plays an important role in the photocatalytic activities of the synthesized ZnO nanofibers.

Microwave Assisted Synthesis of SnS Decorated Graphene Nanocomposite with Efficient Visible-Light-Driven Photocatalytic Applications

  • Wang, Jun-Hui;Zeng, Yi-Kai;Gu, Hao;Zhu, Lei;Oh, Won-Chun
    • Korean Journal of Materials Research
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    • v.30 no.12
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    • pp.641-649
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    • 2020
  • A facile microwave assisted solvothermal process is designed for fabricating SnS nanoparticles decorated on graphene nanosheet, which used as visible light driven photocatalyst. Some typical characterization techniques such as XRD, FT-IR, SEM with EDX analysis, and TEM and BET analysis are used to analyse the physical characteristics of as-prepared samples. Spherical SnS nanoparticles are uniformly dispersed on the surface of graphene nanosheet due to ammonia, which can prevent the aggregation of graphene oxide. Meanwhile, microwave radiation provides fast energy that promotes the formation of spherical SnS nanoparticles within a short time. The visible light photocatalytic activity of as-prepared SnS-GR nanocomposites is analysed through photodegradation efficiency of methylene blue with high concentration. According to the higher photocatalytic property, the as-prepared SnS-GR nanocomposites can be expected to be an efficient visible light driven photocatalyst. After five cycles for decolorization, the rate decreases from 87 % to 78 % (about 9 %). It is obvious that the photocatalytic activity of SnS-GR nanocomposite has good repeatability.

Enhanced photocatalytic performance of magnesium-lithium co-doped BiVO4 and its degradation of methylene blue

  • Nayoung Kim;Hyeonjin Kim;Jiyu Lee ;Seog-Young Yoon
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.33 no.4
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    • pp.132-138
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    • 2023
  • Doped and undoped-BiVO4 samples with different elements (Li, Mg) and amounts were synthesized with a hydrothermal method. The synthesized samples were characterized using various techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis diffusion reflectance spectroscopy (UV-Vis DRS), and photoluminescence (PL) spectroscopy. Photocatalytic activity of the samples was evaluated by measuring the degradation of methyl blue (MB) under visible light irradiation. The results indicated that the incorporation of Mg and Li into BiVO4 caused lattice distortion, the presence of surface hydroxyl groups, a narrower band gap, and a reduced recombination ratio of photo-induced electron-hole pairs. Notably, the photocatalytic activity of Mg5%-Li5% co-doped BiVO4 sample exhibited a significant improvement compared to that of undoped BiVO4 sample.