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RISS 인기검색어
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- 저자 : Byeongkil Shin (검색결과 4 건)
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Byeongkil Shin,Heesoo Lee,Hyun Park 대한금속재료학회(구 대한금속학회) 2016 대한금속·재료학회지 Vol.54 No.10
The effect of added WO₃ on the catalytic activity and surface characteristics of the MnOx-TiO₂ system was investigated for the low-temperature selective catalytic reduction of NOx with NH₃. Based on physio-chemical characterizations, the specific surface areas of the WO₃-MnOx-TiO₂ catalysts increased from 76.12m²/g to 90.29m²/g as the WO₃ content increased, and crystallinity of the anatase TiO₂ phase decreased. The NOx conversion efficiency of the WO₃-MnOx-TiO₂ catalysts with WO₃ contents was over 70% at 200 °C, and their efficiency was over 90% at 300 °C. The results of Fourier transform infrared spectroscopy indicated that the 1438 and 1632 cm-1 values, which were assigned to Lewis and Brønsted acid sites, increased with the increase in WO₃ content. The enhanced catalytic acidity originated from changes to the physical and chemical structures on the surface. MmOx formed on the TiO₂ surface of the 15 wt% WO₃-doped MnOx-TiO₂, and amorphous state Mn2O3 (Mn3+) and WO3 (W6+) existed on the surface, which led to the improved Lewis and Brønsted acid sites, respectively.
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Shin, Byeongkil,Chun, Ho Hwan,Cha, Jin-Sun,Shin, Min-Chul,Lee, Heesoo American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.5
<P>The effects of CeO2 addition on the catalytic activity and the SO2 resistance of CeO2-doped MnOx-TiO2 catalysts were investigated for the low-temperature selective catalytic reduction (SCR) with NH3 of NOx emissions in marine applications. The most active catalyst was obtained from 30 wt% CeO2-MnOx-TiO2 catalyst in the whole temperature range of 100-300 degrees C at a low gas hourly space velocity (GHSV) of 10,000 h-1, and its de-NOx efficiency was higher than 90% over 250 degrees C. The enhanced catalytic activity may contribute to the dispersion state and catalytic acidity on the catalyst surface, and the highly dispersed Mn and Ce on the nano-scaled TiO2 catalyst affects the increase of Lewis and Bronsted acid sites. A CeO2-rich additive on MnOx-TiO2 could provide stronger catalytic acid sites, associated with NH3 adsorption and the SCR performance. As the results of sulfur resistance in flue gas that contains SO2, the de-NOx efficiency of MnOx-TiO2 decreased by 15% over 200 degrees C, whereas that of 30 wt% ceria-doped catalyst increased by 14-21% over 150 degrees C. The high SO2 resistance of CeO2-MnOx-TiO2 catalysts that resulted from the addition of ceria suppressed the formation of Mn sulfate species, which led to deactivation on the surface of nano-catalyst.</P>
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무기계 MnO<sub>x</sub>-WO<sub>3</sub>-TiO<sub>2</sub> 나노분말의 표면특성 및 자기마모형 수지 적용성 평가
신병길,박현,Shin, Byeongkil,Park, Hyun 해양환경안전학회 2016 海洋環境安全學會誌 Vol.22 No.2
선박 및 해양구조물에서의 생물학적 오손을 방지하기 위하여 나노크기의 $MnO_x-WO_3-TiO_2$ 분말을 졸겔법으로 합성하여 특성을 제어하였고, 입자의 결정과 미세구조 등 분체특성 평가를 실시하였다. 자기마모형 방오도료의 안료에 적용하기 위하여 수지에 첨가된 $TiO_2$계 나노분말 안료의 함량에 따른 표면특성 및 방오성능을 확인하였다. $TiO_2$계 안료의 분체특성으로 비표면적은 약 $90m^2/g$, 입자크기는 약 100 ~ 150 nm을 보였다. 텅스텐 산화물은 망간산화물과 티타늄산화물과 상관관계를 통해, 삼원계 분체가 분체특성 및 표면특성이 우수하였다. 망간산화물의 첨가는 독특한 산화환원 특성으로 인하여 방오성능을 증가시키고, 텅스텐 산화물은 안료의 분체특성을 향상시킴으로, 안료와 수지의 비율을 조절하여 분산성, 표면특성 및 방오성능을 제어하였다. 그 결과로, 분산성 및 표면특성에 있어서 1, 5 wt. % 안료가 첨가된 것이 일부 우수하였으나, 5개월 동안의 해상침지시험에서는 2 wt. % 함유된 시편이 높은 방오성능을 보여 해양구조물의 방오안료 적용가능성을 확인하였다. The $MnO_x-WO_3-TiO_2$ nanoscale powders were synthesized by sol-gel method in order to prevent the biological fouling on the ships and offshore structures. Powder characteristics and antifouling performance were investigated with respect to the crystalline, microstructure and surface property for application in self-polishing copolymer resins. The high antifouling activity of $TiO_2$-system biocide was attributed to its redox potential and soluble metal ions originating from tungsten oxides according to the improvements in the powder characteristics. Based on their physio-chemical characterizations, the specific surface areas of powders were about $90m^2/g$ and the grain size was in the region 100 ~ 150 nm. Powder characteristics and surface properties were improved by the addition of $WO_3$. Antifouling performance were analyzed according to their surface properties and static immersion tests to determine the effects of the $TiO_2$-system compounds. The surface of 2 wt. % added sample was clean for 5 month. This may be attributed to the ability of $MnO_x-WO_3-TiO_2$ powders to act as a promoter in antifouling agents.
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CeO<sub>2</sub>가 졸겔법으로 합성한 CeO<sub>2</sub>-TiO<sub>2</sub>계 SCR용 촉매의 활성에 미치는 물리화학적 영향
김부영,신병길,이희수,전호환,Kim, Buyoung,Shin, Byeongkil,Lee, Heesoo,Chun, Ho Hwan 한국결정성장학회 2013 한국결정성장학회지 Vol.23 No.6
$CeO_2$의 첨가가 $CeO_2-TiO_2$계 SCR촉매 활성에 미치는 영향을 구조적, 형상학적, 물리화학적 분석을 통해 규명하였다. 순수한 $TiO_2$ 분말과 10, 20, 30 wt%의 $CeO_2$를 첨가한 $CeO_2-TiO_2$ 분말을 졸겔법으로 합성한 결과, 분말 모두 $TiO_2$의 아나타제 (anatase)상을 나타내었고 $CeO_2$를 첨가할수록 $TiO_2$ 표면에 결정성이 낮은 $CeO_2$가 분산되어 피크강도가 낮아짐을 확인하였다. 순수한 $TiO_2$의 비표면적이 $60.6306m^2/g$인데 반해 $CeO_2-TiO_2$의 비표면적은 30 wt%의 $CeO_2$를 첨가한 경우 $116.2791m^2/g$으로 비표면적이 증가하였고 따라서 첨가된 $CeO_2$가 $TiO_2$의 응집을 억제한 것으로 예상된다. $NO_x$ 제거효율은 30 wt% $CeO_2-TiO_2$ 촉매가 $300^{\circ}C$에서 98 %로 다른 분말보다 높은 효율을 나타내는데 이는 FT-IR을 이용하여 촉매의 산점 변화를 확인한 결과 30 wt% $CeO_2-TiO_2$ 분말의 경우가 다른 분말들에 비해 산점이 상대적으로 많았기 때문이다. 따라서 졸겔법으로 합성한 SCR용 $CeO_2-TiO_2$계 촉매에서 $CeO_2$의 첨가는 $TiO_2$의 입성장을 억제하여 비표면적을 증가시키고 $Br{\Phi}nsted$ 및 Lewis 산점을 증가시킴으로써 촉매 효율을 향상시켰다고 판단된다. The effects of $CeO_2$ on catalytic activity of $CeO_2-TiO_2$ for the selective catalytic reduction (SCR) of $NO_x$ were investigated in terms of structural, morphological, and physico-chemical analyseis. $CeO_2-TiO_2$ catalysts were synthesized with three different additions, 10, 20, and 30 wt% of $CeO_2$, by the sol-gel method. The XRD peaks of all specimens were assigned to a $TiO_2$ phase (anatase) and the peaks became broader with the addition of $CeO_2$ because it was dispersed as an amorphous phase on the surface of $TiO_2$ particles. The specific surface area of $TiO_2$ increased with the addition of $CeO_2$ from $60.6306m^2/g$ to $116.2791m^2/g$ due to suppression of $TiO_2$ grain growth by $CeO_2$. The 30 wt% $CeO_2-TiO_2$ catalyst, having the strongest catalytic acid sites ($Br{\Phi}nsted$ and Lewis), showed the highest $NO_x$ conversion efficiency of 98 % at $300^{\circ}C$ among the specimens. It was considered that $CeO_2$ contributes to the improvement of the $NO_x$ conversion of $CeO_2-TiO_2$ catalyst by increasing specific surface area and catalytic acid sites.
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