• Title/Summary/Keyword: Photocatalytic

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Synthesis of ZnS:Mn-Gly-C60 Nanocomposites and Their Photocatalytic Activity of Brilliant Green

  • Li, Jiulong;Ko, Weon Bae
    • Elastomers and Composites
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    • v.53 no.2
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    • pp.75-79
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    • 2018
  • ZnS:Mn-glycine (ZnS:Mn-Gly) nanocomposites were synthesized by capping ZnS:Mn nanocomposites with glycine. Zinc sulfate heptahydrate ($ZnSO_4{\cdot}7H_2O$), glycine ($C_2H_5NO_2$), manganese sulfate monohydrate ($MnSO_4{\cdot}H_2O$), and sodium sulfide ($Na_2S$) were used as the source reagents. $ZnS:Mn-Gly-C_{60}$ nanocomposites were obtained by heating the ZnS:Mn-Gly nanocomposites and fullerene ($C_{60}$) at a 2:1 mass ratio in an electric furnace at $700^{\circ}C$ for 2 h. X-ray diffraction (XRD) was used to characterize the crystal structure of the synthesized nanocomposites. The photocatalytic activity of the $ZnS:Mn-Gly-C_{60}$ nanocomposites was evaluated, via the degradation of brilliant green (BG) dye under 254 nm irradiation, with a UV-vis spectrophotometer.

Influence of MAO Conditions on TiO2 Microstructure and Its Photocatalytic Activity (MAO 공정 변수가 TiO2 산화피막의 구조 및 광촉매 특성에 미치는 영향)

  • Kim, Jeong-Gon;Kang, In-Cheol
    • Journal of Powder Materials
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    • v.19 no.3
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    • pp.196-203
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    • 2012
  • $TiO_2$ was successfully formed on a Ti specimen by MAO (Micro-Arc-Oxidation) method treated in $Na_3PO_4$ electrolyte. This study deals with the influence of voltage and working time on the change of surface microstructure and phase composition. Voltage affected the forming rate of the oxidized layer and surface microstructure where, a low voltage led to a high surface roughness, more holes and a thin oxidized layer. On the other hand, a high voltage led to more dense surface structure, wider surface holes, a thick layer and fewer holes. Higher voltage increases photocatalytic activity because of better crystallization of the oxidized layer and good phase composition with anatase and rutile $TiO_2$, which is able to effectively separate excited electrons and holes at the surface.

PHOTOCATALYTIC DEGRADATION OF 2-CHLOROPHENOL USING TiO₂THIN FILMS PREPARED BY CHEMICAL VAPOR DEPOSITION AND ION BEAM SPUTTERING METHOD

  • Jung, Oh-Jin;Kim, Sam-Hyeok;Jo, Ji-Eun;Hwang, Chul-Ho
    • Environmental Engineering Research
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    • v.7 no.4
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    • pp.227-237
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    • 2002
  • Chemical vapor deposition (CVD), ion beam sputtering (IBS) and sol-gel method were used to prepare TiO$_2$ thin films for degradation of hazardous organic compounds exemplified by 2-chlorophenol (2-CP). The influence of supporting materials and coating methods on the photocatalytic activity of the TiO$_2$ thin films were also studied. TiO$_2$ thin films were coated onto various supporting materials including steel cloth (SS), copper cloth, quartz glass tube (QGT), and silica gel (SG). Results indicate that SS (37 μm)- TiO$_2$ thin film prepared by IBS method improves the photodegradation of 2-CP. Among all supporting materials studied, SS(37 μm) is found to be the best support.

Enhanced Visible Light Activity and Stability of TiO2 Nanopowder by co-doped with Mo and N

  • Hu, Shaozheng;Li, Fayun;Fan, Zhiping
    • Bulletin of the Korean Chemical Society
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    • v.33 no.4
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    • pp.1269-1274
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    • 2012
  • A visible light responsive N, Mo co-doped $TiO_2$ were prepared by sol-gel method. X-ray diffraction, TEM, $N_2$ adsorption, UV-vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared $TiO_2$ samples. Doping restrained the phase transformation from anatase to rutile and reduced the particle sizes. The band gap was much narrowed after N, Mo co-doping. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activities of doped $TiO_2$ were much higher than that of neat $TiO_2$. The photocatalytic stability of N, Mo co-doped $TiO_2$ was much better than that of N doped $TiO_2$.

Photocatalytic Decolorization of Dye Using Packed-bed Reactor and Immobilized TiO2/UV System (충전층 반응기와 고정화 TiO2/UV를 이용한 Rhodamine B의 광촉매 탈색)

  • Kim, Dong-Seog;Park, Young-Seek
    • Journal of Environmental Science International
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    • v.16 no.3
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    • pp.255-260
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    • 2007
  • The photocatalytic decolorization of Rhodamine B (RhB) was studied using packed-bed reactor and immobilized $TiO_2/UV$ System. The 20 W UV-A, UV-B and UV-C lamps were employed as the light source. The effect of shape and surface polishing extent of reflector, distance between the reactor and reflector, reactor material were investigated. The results showed that the order of the initial reaction constant with reflector shape was round > polygon > W > rhombus. The optimum distance between the reactor and reflector was 2 cm. The initial reaction constant of quartz reactor was 1.46 times higher than that of tile PVDF reactor.

Physical properties of mungbean starch/PVA bionanocomposites added nano-ZnS particles and its photocatalytic activity

  • Yun, Yeon-Hum;Kim, Eun-Sik;Shim, Wang-Geun;Yoon, Soon-Do
    • Journal of Industrial and Engineering Chemistry
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    • v.68
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    • pp.57-68
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    • 2018
  • The main objective of this study is to prepare the bionanocomposite films using mungbean starch (MBS), PVA, ZnS, and plasticizers, and to evaluate the physical properties, thermal stability, and photocatalytic activity. The bionanocomposite films were cross-linked by heat-curing process. The ZnS and bionanocomposite films were characterized by FT-IR, XRD, and SEM. The results indicated that the mechanical properties and water resistance enhanced up to 1.2-1.5 times by the addition of nano-ZnS particles, and the thermal stability was improved by the addition of nano-ZnS particles. The photocatalytic activity of the bionanocomposite films added nano-ZnS particles was examined using bisphenol A (BPA) and methyl orange (MO). In addition, the photodegradation efficiency of BPA and MO was evaluated using the pseudo-first order kinetic model (PFOK).

Effect of Heat Treatment and Platinum Loading on CdS Particles in the Photocatalytic Alanine Synthesis

  • Lee, Bu-Yong;Kim, Bong-Gon;Cho, Cheol-Rae;Sakada, Tadayoshi
    • Bulletin of the Korean Chemical Society
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    • v.14 no.6
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    • pp.700-704
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    • 1993
  • The photocatalytic alanine and hydrogen production reaction were studied by using CdS as a semiconductor photocatalysts. The rate of alanine and hydrogen production depends strongly on the temperature in heat treatment of CdS powder. In particular, the rate of alanine production, which was observed using Pt/CdS(A)-(CdS from Mitsuwa), was increased about six times than that of using Pt/CdS(B)-(CdS from Furruchi) under the same heat treatment condition at 500$^{\circ}$C. And the photocatalytic activity for alanine production using bare CdS(A) or Pt/CdS(A) was almost same with increasing temperature in heat treatment in the range of 100-600$^{\circ}$C. From X-ray diffraction data and photoluminescence spectrum, we conclude that the crystal structure changes of CdS(A) or strong interaction at interface of Pt and CdS contribute to increasing the rate of alanine and hydrogen production reaction.

Synergistic Effect on the Photocatalytic Degradation of 2-Chlorophenol Using $TiO_2$Thin Films Doped with Some Transition Metals in Water

  • Jeong, O Jin
    • Bulletin of the Korean Chemical Society
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    • v.22 no.11
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    • pp.1183-1191
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    • 2001
  • The metallorganic chemical vapor deposition (MOCVD) method has been used to prepare TiO2 thin films for the degradation of hazardous organic compounds, such as 2-chlorophenol (2-CP). The effect of supporting materials and metal doping on the photocatalytic activity of TiO2 thin films also has been studied. TiO2 thin films were coated onto various supporting materials, including stainless steel cloth(SS), quartz glass tube (QGT), and silica gel (SG). Transition metals, such as Pd(II), Pt(IV), Nd(III) and Fe(III), were doped onto TiO2 thin film. The results indicate that Nd(Ⅲ) doping improves the photodegradation of 2-CP. Among all supporting materials studied, SS(37 ${\mu}m)$ appears to be the best support. An optimal amount of doping material at 1.0 percent (w/w) of TiO2-substrate thin film gives the best photodegration of 2-CP.

UV Light Induced Photocatalytic Degradation of Cyanides in Aqueous Solution over Modified $TiO_2$

  • Kim, Hyeong Ju;Kim, Jae Hyeon;Lee, Cheong Hak;Hyeon, Taek Hwan;Choe, Won Yong;Lee, Ho In
    • Bulletin of the Korean Chemical Society
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    • v.22 no.12
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    • pp.1371-1374
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    • 2001
  • Metal doping was adopted to modify TiO2 (P-25) and enhance the photocatalytic degradation of harmful cyanides in aqueous solution. Ni, Cu, Co, and Ag doped TiO2 were found to be active photocatalysts for UV light induced degradation of aqueous cyanides generating cyanate, nitrate and ammonia as main nitrogen-containing products. The photoactivity of Ni doped TiO2 was greatly affected by the state of Ni, that is, the crystal size and the degree of reduction of Ni. The modification effects of some mixed oxides, that is, Ni-Cu/TiO2 were also studied. The activity of Ni-Cu/TiO2 for any ratio of Cu/Ni was higher than that of Ni- or Cu-doped TiO2, and the catalyst at the Cu/Ni ratio of 0.3 showed the highest activity for cyanide conversion.

Solvothermal synthesis of photocatalytic $TiO_2$ nanoparticles in toluene

  • Kim, Chung-Sik;Moon, Byung-Kee;Park, Jong-Ho;Park, Byung-Chun;Seo, Hyo-Jin
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.07a
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    • pp.300-301
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    • 2003
  • Nowadays as the concerns with global environmental issue increase, the application of TiO$_2$ to the treatment of polluted air and wastewater has become more and more widespread because of its promising photocatalytic performance. The photocatalytic activity of TiO$_2$ is greatly influenced by its crystal structure, particle size, surface area and porosity. (omitted)

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