• Title/Summary/Keyword: Turn Over Frequency(TOF)

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Chemical Doping of $TiO_2$ with Nitrogen and Fluorine and Its Support Effect on Catalytic Activity of CO Oxidation

  • Chakravarthy, G. Kalyan;Kim, Sunmi;Kim, Sang Hoon;Park, Jeong Young
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.142.2-142.2
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    • 2013
  • The effect of substrate on catalytic activity of CO oxidation with transition metal Platinum nanoparticles on doped and undoped TiO2 was investigated. Titanium dioxide was doped chemically with non-metal anions including nitrogen and fluorine. Undoped TiO2 was synthesized via simple conventional sol-gel route. Thin films of titania were developed by spin coating technique and the characterization techniques SEM, XRD, UV-Vis Absorption Spectroscopy and XPS were carried out to examine the morphology of films, crystal phase, crystallites, optical properties and elemental composition respectively. XPS analysis from doped TiO2 confirmed that the nitrogen site were interstitial whereas fluorine was doped into TiO2 lattice substitutionally. Catalytic activity systems of Pt/doped-TiO2 and Pt/undoped-TiO2 were fabricated to reveal the strong metal-support interaction effect during catalytic activity of CO oxidation reactions. By arc plasma deposition technique, platinum nanoparticles with mean size of 2.7 nm were deposited on the thin films of doped and undoped titanium dioxide. The CO oxidation was performed with 40 Torr CO and 100 Torr O2 with 620 Torr He carrier gas. Turn over frequency was observed two to three folds enhancement in case of Pt/doped TiO2 as compared to Pt/TiO2. The electronic excitation and the oxygen vacancies that were formed with the doping process were the plausible reasons for the enhancement of catalytic activity.

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Effect of Vanadium Surface Density of SCR Catalyst on Reaction Activity and SO2 Durability (상용 SCR 촉매의 바나듐 표면밀도가 반응활성 및 SO2 내구성에 미치는 영향연구)

  • Won, Jong Min;Park, Kwang Hee;Hong, Sung Chang
    • Applied Chemistry for Engineering
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    • v.28 no.2
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    • pp.158-164
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    • 2017
  • In this study, the reaction activity and XRD, BET, and Raman analysis were performed to verify $NH_3$-SCR reaction characteristics of various commercial SCR catalysts. It can be seen that the reaction rate of each commercial SCR catalyst increased linearly with increasing the vanadium content (1.3-5.4 wt%). In addition, through the above analysis, it was possible to confirm that the addition of WOx in the catalyst increased the Turn over frequency (TOF) within the range where the VOx surface density was more than 8.1 and the crystalloid VOx was not formed through the surface structure analysis. $SO_2$ durability tended to decrease with increasing the vanadium content, and the durability increased the most when W and Si were added.