• Title, Summary, Keyword: photodeposition

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Antimicrobial Treatment of Polyurethane Membrane Using Photodeposition of Nano-titanium Dioxide and Nano-silver (나노 TiO2와 나노 은의 광증착을 이용한 폴리우레탄 멤브레인의 항균성 부여 연구)

  • Sul, In Hwan;Kim, Young-A;Lee, Hyun Jeong;Chae, Seog;Min, Byung Gil
    • Textile Science and Engineering
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    • v.50 no.5
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    • pp.315-322
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    • 2013
  • Polyurethane membrane was chosen as an alternate for Gore-Tex$^{(R)}$ used in outdoor sportswear. Antimicrobial property was induced by dispersing titanium dioxide ($TiO_2$) particles on the surface of the membrane via sonication. Furthermore, Ag particle was photodeposited on the $TiO_2$ particles via UV irradiation to enhance the photocatalytic activity. Measurements using X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy showed that $TiO_2$ and Ag particles were evenly deposited on the membrane. In addition, the antimicrobial property against Klebsiella pneumoniae and Staphylococcus aureus was validated using the shake flask method and clear zone method.

Antimicrobial Properties of PET/(Nano-TiO2) Composite Films Prepared by Photocatalytic Deposition of Silver (나노 은을 광증착시킨 폴리(에틸렌 테레프탈레이트)/나노-TiO2 복합체의 항균특성 연구)

  • Jo, Seong-Min;Jhee, Kwang Hwan;Kim, Jung Hyun;Kwon, Oh Kyung;Lim, Sang Kyoo;Min, Byung Gil
    • Textile Science and Engineering
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    • v.49 no.6
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    • pp.377-382
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    • 2012
  • Nanocomposite films of poly(ethylene terephthalate)(PET) and nano titania($TiO_2$) were prepared by melt compounding with a twin-screw extruder followed by hot pressing for the purpose of investigating antibacterial activity. FE-SEM, EDS and XRD measurements confirmed that nano $TiO_2$ was successfully dispersed at the level of individual particles in the PET matrix. Silver was introduced through photocatalytic reduction by nano $TiO_2$ under UV (254 nm) irradiation to the nanocomposite films after being immersed in aqueous solution $AgNO_3$ (100 ppm Ag ion). Even at 1 wt% of $TiO_2$ content, the nanocomposite with silver photodeposition exhibited strong antimicrobial activity against Klebsiella pneumoniae and Staphylococcus aureus in measurement by shaking flask method.

Photocatalytic Decomposition of Gaseous Acetaldehyde by Metal Loaded $TiO_2$ with Ozonation

  • Cho, Ki-Chul;Yeo, Hyun-Gu
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.E1
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    • pp.19-26
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    • 2006
  • The decomposition of gaseous $CH_3CHO$ was investigated by metal loaded $TiO_2$ (pure $TiO_2,\;Pt/TiO_2,\;Pd/TiO_2,\;Mn/TiO_2\;and\;Ag/TiO_2$) with $UV/TiO_2$ process and $UV/TiO_2/O_3$ process at room temperature and atmospheric pressure. Metal loaded $TiO_2$ was prepared by photodeposition. Decomposition of $CH_3CHO$ was carried out in a flow-type photochemical reaction system using three 10W black light lamps ($300{\sim}400nm$) as a light source. The experimental results showed that the degradation rate of $CH_3CHO$ was increased with Pt and Ag on $TiO_2$ compared to pure $TiO_2$, but decreased with depositing Pd and Mn on pure $TiO_2$. The considerable increase in the degradation efficiency of the $CH_3CHO$ was found by a combination of photocatalysis and ozonation as compared to only by ozonation or photocatalysis. Loading of Pt on $TiO_2$ promoted conversion of gaseous ozone. The degradation rate of gaseous $CH_3CHO$ decreased with an increase of water vapor in the feed stream for the both $UV/TiO_2\;and\;UV/TiO_2/O_3$ processes. The pure $TiO_2$ was more affected by the water vapor than Pt loaded $TiO_2$.

Photocatalytic Properties of the Ag-Doped TiO2 Prepared by Sol-Gel Process/Photodeposition (졸-겔공정/광증착법을 이용한 Ag-Doped TiO2 합성 및 광촉매 특성)

  • Kim, Byeong-Min;Kim, Jung-Sik
    • Korean Journal of Materials Research
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    • v.26 no.2
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    • pp.73-78
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    • 2016
  • $TiO_2$ nanoparticles were synthesized by a sol-gel process using titanium tetra isopropoxide as a precursor at room temperature. Ag-doped $TiO_2$ nanoparticles were prepared by photoreduction of $AgNO_3$ on $TiO_2$ under UV light irradiation and calcinated at $400^{\circ}C$. Ag-doped $TiO_2$ nanoparticles were characterized for their structural and morphological properties by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). The photocatalytic properties of the $TiO_2$ and Ag-doped $TiO_2$ nanoparticles were evaluated according to the degree of photocatalytic degradation of gaseous benzene under UV and visible light irradiation. To estimate the rate of photolysis under UV (${\lambda}=365nm$) and visible (${\lambda}{\geq}410nm$) light, the residual concentration of benzene was monitored by gas chromatography (GC). Both undoped/doped nanoparticles showed about 80 % of photolysis of benzene under UV light. However, under visible light irradiation Ag-doped $TiO_2$ nanoparticles exhibited a photocatalytic reaction toward the photodegradation of benzene more efficient than that of bare $TiO_2$. The enhanced photocatalytic reaction of Ag-doped $TiO_2$ nanoparticles is attributed to the decrease in the activation energy and to the existence of Ag in the $TiO_2$ host lattice, which increases the absorption capacity in the visible region by acting as an electron trapper and promotes charge separation of the photoinduced electrons ($e^-$) and holes ($h^+$). The use of Ag-doped $TiO_2$ nanoparticles preserved the option of an environmentally benign photocatalytic reaction using visible light; These particles can be applicable to environmental cleaning applications.

Photoelectrochemical Water Oxidation Using ZnO Nanorods Coupled with Cobalt-Based Catalysts

  • Jeon, Tae-Hwa;Choi, Sung-Kyu;Jeong, Hye-Won;Kim, Seung-Do;Park, Hyun-Woong
    • Journal of Electrochemical Science and Technology
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    • v.2 no.4
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    • pp.187-192
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    • 2011
  • Photoelectrochemical performances of ZnO electrodes are enhanced by coupling with cobalt-based catalyst (CoPi) in phosphate electrolyte (pH 7). For this study, hexagonal pillar-shaped ZnO nanorods are grown on ZnO electrodes through a chemical bath deposition, onto which CoPi is deposited with different photodeposition times (10-30 min). A scanning electron microscopic study indicates that CoPi deposition does not induce any change of ZnO morphology and an energy-dispersive X-ray spectroscopic analysis shows that inorganic phosphate ions (Pi) exist on ZnO surface. Bare ZnO electrodes generate the current of ca. $0.36mA/cm^2$ at a bias potential of 0.5 V vs. SCE, whereas ZnO/CoPi (deposited for 10 min) has ca. 50%-enhanced current ($0.54mW/cm^2$) under irradiation of AM 1.5G-light ($400mW/cm^2$). The excess loading of CoPi on ZnO results in decrease of photocurrents as compared to bare ZnO likely due to limited electrolyte access to ZnO and/or CoPi-mediated recombination of photogenerated charge carriers. The primary role of CoPi is speculated to trap the photogenerated holes and thereby oxidize water into molecular oxygen via an intervalency cycle among Co(II), Co(III), and Co(IV).

Preparation and Antimicrobial Properties of Nylon 6/Nano-TiO2 Nanohybrids (나일론 6/나노-TiO2 유·무기 하이브리드의 제조 및 항균특성 연구)

  • Lee, Duk Hyeong;Jo, Seong Min;Min, Byung Gil
    • Textile Science and Engineering
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    • v.51 no.4
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    • pp.193-199
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    • 2014
  • Nanohybrids of nylon 6 and nano-titania ($TiO_2$) were prepared by melt compounding with a twin-screw extruder to investigate antibacterial activity. It was confirmed by field emission scanning electron microscopy (FESEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD) that nano-$TiO_2$ was successfully dispersed in the nylon 6 matrix at the level of individual particles. After immersion in an aqueous solution of $AgNO_3$ at 100 ppm Ag ion concentration, silver was introduced to the nanohybrids through photocatalytic reduction by nano-$TiO_2$ under UV (254 nm) irradiation. With increasing nano-$TiO_2$ content, the nanohybrids with silver photodeposited on the nano-$TiO_2$. The nylon $6/TiO_2$-Ag nanohybrids exhibited strong antimicrobial activity against Klebsiella pneumoniae and Staphylococcus aureus in measurements with the shaking flask method.

Hybrid between Inorganic Material and Biological Photosystem1 for Light Energy Application

  • Kim, Yeong-Hye;Nam, Gi-Tae
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.272-272
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    • 2013
  • The attractive features of photosynthetic reaction center proteins for energy application make them useful in solar energy conversion to hydrogen fuel or electrical energy. Almost unity charge separation quantum yield and its rapid speed of ~1ns, absorbance region in visible light (480~740 nm) and high proportion of photosynthetically active solar energy of 48.5% allowed photosystem1 to exploited as a bio-material for photo-energy devices. Directionality of photosystem1 in electron transfer can solve main problem in two-step water splitting process where back reaction deteriorates the overall efficiency. In the study, photosystem1 was extracted from spinach and the photo-induced excited electron in the reaction center was utilized in various field of light energy application. First, hydrogen evolving system realized by photodeposition of platinum at the end of the electron transfer chain, with combining specific semiconductor to oxidize water in the first step of Z-scheme. The evaluation by gas-chromatography demonstrated hydrogen evolution through the system. For the further application of photoelectrical material on electrode, photosystem1 have been controlled by copper ion, which is expected to assemble photosystem in specific orientation followed by maximized photoelectrical ability of film. The research proposed concrete methods for combining natural protein and artificial materials in one system and suggested possibility of designing interface between biological and inorganic materials.

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Few-Layered MoS2 Nanoparticles Loaded TiO2 Nanosheets with Exposed {001} Facets for Enhanced Photocatalytic Activity

  • Chen, Chujun;Xin, Xia;Zhang, Jinniu;Li, Gang;Zhang, Yafeng;Lu, Hongbing;Gao, Jianzhi;Yang, Zhibo;Wang, Chunlan;He, Ze
    • Nano
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    • v.13 no.11
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    • pp.1850129.1-1850129.10
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    • 2018
  • To improve the high charge carrier recombination rate and low visible light absorption of {001} facets exposed $TiO_2$ [$TiO_2(001)$] nanosheets, few-layered $MoS_2$ nanoparticles were loaded on the surfaces of $TiO_2(001)$ nanosheets by a simple photodeposition method. The photocatalytic activities towards Rhodamine B (RhB) were investigated. The results showed that the $MoS_2-TiO_2(001)$ nanocomposites exhibited much enhanced photocatalytic activities compared with the pure $TiO_2(001)$ nanosheets. At an optimal Mo/Ti molar ratio of 25%, the $MoS_2-TiO_2(001)$ nanocomposites displayed the highest photocatalytic activity, which took only 30 min to degrade 50 mL of RhB (50 mg/L). The active species in the degradation reaction were determined to be $h^+$ and $^{\bullet}OH$ according to the free radical trapping experiments. The reduced charge carrier recombination rate, enhanced visible light utilization and increased surface areas contributed to the enhanced photocatalytic performances of the 25% $MoS_2-TiO_2(001)$ nanocomposites.

Synthesis of Visible-working Pt-C-TiO2 Photocatalyst for the Degradation of Dye Wastewater (염료폐수 분해를 위한 가시광 감응형 Pt-C-TiO2 광촉매의 합성)

  • Hahn, Mi Sun;Yun, Chang Yeon;Yi, Jongheop
    • Clean Technology
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    • v.11 no.3
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    • pp.123-128
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    • 2005
  • Among various metal oxides semiconductors, $TiO_2$ is the most studied semiconductor for environmental clean-up applications due to its unique ability in photocatalyzing various organic contaminants, its chemical inertness, and nontoxicity. $TiO_2$, however, has a few drawbacks to be solved such as reactivity mainly working under ultraviolet irradiation (${\lambda}$ < 387 nm) and electron - hole recombination on $TiO_2$. In this study, to extend the absorption range of $TiO_2$ into the visible range and enhance electron - hole separation, we synthesized platinum (Pt) deposited $C-TiO_2$. The presence of Pt as an electron sink has been known to snhance the separation of photogenerated electron-hole pairs and induce the thermal decomposition. The characterization of as-synthesized $Pt-C-TiO_2$ was performed by Transmission Electron Microscopic (TEM), the Brunuer-Emmett-Teller (BET) method, X-ray Diffractometer (XRD), UV-vis spectrometer (UV-DRS), and X-ray Photoelectron Spectroscopy (XPS). In order to estimate the photocatalytic activity of the synthesized materials, the photoelectron Spectroscopy (XPS). In order to estimate the photocatalytic activity of the synthesized materials, the photodegradation experiment of an azo dye (Acid Red 44; $C_{10}H_7N=NC_{10}H_3(SO_3Na)_2OH$)was carried out by using an Xe arc lamp (300 W, Oriel). A 420 nm cut-off filter was used for visible light irradiation. From the results, Pt-deposited $C-TiO_2$ showed a far superior phothdegradation activity to Degussa P25, the commercial product under the irradiation of visible light and enhanced photocatalytic activity of visible-working $C-TiO_2$. This is a useful result into the application for the purification system of dye wastewater using visible energy of sun light.

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