• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.28.2-28.2
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• 2011

The selective catalytic reduction (SCR) of NOx by $NH_3$ is well known as one of the most convenient, efficient, and economical method to prevent NOx emission in flue gas from stationary sources. The degradation of the reactivity is the obstacle for its real application, since high concentrations of sulfur dioxide and thermal factor would deactivate the catalyst. It is necessary to develop high stability of catalysts for low-temperature SCR. Among the transition metal oxides, $WO_3$ is known to exhibit high SCR activity and good thermal stability. The $MnOx-WO_3-TiO_2$ catalysts prepared by sol-gel method with various $WO_3$ contents were investigated for low-temperature SCR. These catalysts were observed in terms of micro-structure and spectroscopy analyses. The $WO_3$ catalyst as a promoter is used to enhance the thermal stability of catalyst since it increases the phase transition temperature of $TiO_2$ support. It was found that the addition of tungsten oxides not only maintained the temperature window of NO conversion but also increased the acid sites of catalyst.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.83-90
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• 2004

Plasma/catalyst combined reactor was designed to overcome the limits of plasma and catalyst technologies. Optimum reductant and catalyst was selected from screening test. Experiments about the concentrations of reactant and $H_2O$ and the effect of temperature were carried out. Hydrocarbons with double bond such as propylene and so on were more reactive than any other reductants in plasma/catalyst condition. Photocatalyst, especially hombikat >$TiO_2$ with the largest surface area among the catalysts tested, showed the highest DeNOx efficiency in plasma/catalyst reaction. As the concentration of $H_2O$ increased, the removal of NO was enhanced. The increased concentration of >$O_2$ promoted the reaction of NO which was oxidized to$NO_2$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4672-4678
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• 2013

Aluminum dross is formation at the surface of the molten metal as the latter reacts with the furnace atmosphere and it was an unavoidable by-product of the aluminum production process. However aluminum dross was usually landfilled or disposed without treatment, causing much environmental damage. The purpose of this study is to investigate the possibility of ceramic catalyst support using recycled Al dross. The recycled Al dross was made into SCR catalyst by mixing with $WO_3$, $V_2O_5$ and $TiO_2$. The $V_2O_5-WO_3/TiO_2-Al_2O_3$ SCR catalyst was observed with XRF, XRD and BET. $V_2O_5-WO_3/TiO_2-Al_2O_3$ SCR strength was measured by Universal Testing Machine(UTM). As the added $Al_2O_3$, streagth is increased. And the NOx removal activity was observed by MR(Micro-Reactor). The temperatures ranging from $350^{\circ}C$ and $400^{\circ}C$, $V_2O_5-WO_3/TiO_2-Al_2O_3$ SCR catalyst De-NOx performance result of showed excellent activity over 90% at application condition.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1209-1215
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• 2022

The selective catalytic reduction (SCR) is known as a very efficient method to reduce nitrogen oxides (NOx) and the catalyst performs reduction from nitrogen oxides (NOx) to nitrogen (N₂) and water vapor (H2O). The catalyst, which is one of the factors determining the performance of the nitrogen oxide (NOx) ruduction method, is known to increase catalyst efficiency as cell density increases. In this study, the reduction characteristics of nitrogen oxides (NOx) under various engine loads investigated. A 100CPSI(60Cell) catalysts was studied through a laboratory-sized simulating device that can simulate the exhaust gas conditions from the power generation engine installed in the training ship SEGERO. The effect of 100CPSI(60Cell) cell density was compared with that of 25.8CPSI(30Cell) cell density that already had NOx reduction data from the SCR manufacturing. The experimental catalysts were honeycomb type and its compositions and materials of V₂O₅-WO₃-TiO₂ were retained, with only change on cell density. As a result, the NOx concentration reduction rate from 100CPSI(60Cell) catalyst was 88.5%, and IMO specific NOx emission was 0.99g/kwh satisfying the IMO Tier III NOx emission requirement. The NOx concentration reduction rate from 25.8CPSI(30Cell) was 78%, and IMO specific NOx emission was 2.00g/kwh. Comparing the NOx concentration reduction rate and emission of 100CPSI(60Cell) and 25.8CPSI(30Cell) catalysts, notably, the NOx concentration reduction rate of 100CPSI(60Cell) catalyst was 10.5% higher and its IMO specific NOx emission was about twice less than that of the 25.8CPSI(30Cell) catalysts. Therefore, an efficient NOx reduction effect can be expected by increasing the cell density of catalysts. In other words, effects to production cost reduction, efficient arrangement of engine room and cargo space can be estimated from the reduced catalyst volume.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.143-144
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• 2001

질소산화물(NOx) 제거기술 중, 선택적촉매환원(Selective Catalytic Reduciton: SCR)공정은 배기가스 중에 포함되어 있는 질소산화물을 암모니아와 촉매상에서 반응시켜 무해한 질소와 물로 전환하는 기술로 높은 탈질율 및 안정적인 기술로 인하여 상업적으로 널리 이용되고 있다(Bosch, 1988). 귀금속촉매, Cu/Zeolite 촉매 및 V$_2$O$_{5}$/TiO$_2$ 등 다양한 촉매들이 SCR 공정에 적용되는데 V$_2$O$_{5}$/TiO$_2$ 촉매가 높은 활성과 황 등 피독 물질에 대한 우수한 내구성으로 인하여 가장 효과적인 촉매로 알려져있다(Heck, 1999). (중략)

• Clean Technology
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• v.22 no.2
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• pp.132-138
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• 2016

The emission of SO₂ is inevitable in case of combustion of most fossil fuels except LNG in commercial power plant which has a bad effect on the durability of SCR catalyst. To develop a low temperature SCR catalyst which has a high NOx removal performance and excellent durability to SO₂, V₂O₅/TiO₂ catalysts were prepared by coating on the metal foam substrate with the impregnation amount of Sb₂O₃ as promotor. This study has evaluated the NOx removal performance and the durability to SO₂ on a laboratory scale atmospheric reactor and analyzed the properties of the prepared catalysts by means of porosimeter, BET, SEM (scanning electron microscope), EDX (energy dispersive x-ray spectrometer), XPS (X-ray photoelectron spectroscopy). It was found that the surface area of catalyst increased with the impregnation amount of Sb₂O₃ and the NOx removal performance showed the highest value at the 2 wt% impregnation of Sb₂O₃. This results was considered to be due to the optimum active site on the catalyst surface. And also, Sb₂O₃ impregnated catalysts presented that NOx removal performance was maintained despite the exposure to SO₂ for 5 hours. Therefore it was confirmed that metal foam SCR catalyst for low temperature could be manufactured with the optimum control of Sb₂O₃ impregnation according to the SO₂ presence or not.

• Korean Journal of Chemical Engineering
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• v.35 no.12
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• pp.2365-2378
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• 2018

We investigated the correlation between vanadium surface density and VOx structure species in the selective catalytic reduction of NOx by $NH_3$. The properties of the $VOx/TiO_2$ catalysts were investigated using physicochemical measurements, including BET, XRD, Raman spectroscopy, FE-TEM, UV-visible DRS, $NH_3-TPD$, $H_2-TPR$, $O_2-On/Off$. Catalysts were prepared using the wet impregnation method by supporting 1.0-3.0 wt% vanadium on $TiO_2$ thermally treated at various calcination temperatures. Through the above analysis, we found that VOx surface density was $3.4VOx/nm^2$, and the optimal V loading amounts were 2.0-2.5 wt% and the specific surface area was $65-80m^2/g$. In addition, it was confirmed that the optimal VOx surface density and formation of vanadium structure species correlated with the reaction activity depending on the V loading amounts and the specific surface area size.

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.584-589
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• 2023

The physicochemical properties of VOx/TiO₂ catalysts with different TiO₂ supports were analyzed, and SCR reactions were performed. VOx/TiO₂ catalysts were prepared by impregnation using anatase TiO₂, which was manufactured by Sigma Aldrich and prepared from TiOCl₂ and titanium isopropoxide (TTIP) as a precursor. They are denoted as VS, VC, and VP. The specific surface area of the VS was 1/10 or less of that of the VC and VP, and the dispersibility of vanadium oxide was relatively low. As a result of XPS analysis, the ratio of adsorbed oxygen was higher in VS and VP with Ti³⁺ than in VC. In VC and VP, vanadium mainly existed in V⁴⁺ and V³⁺ states in relation to the dispersibility of vanadium oxide. The amount of adsorbed oxygen contributed more to NH₃-SCR activity than vanadium oxide dispersibility below 250 ℃, while vanadium oxide dispersibility contributed more to activity beyond 300 ℃. The fast SCR activity in all three samples was the highest at NO₂/NOx = 0.5, followed by VS < VC < VP samples. It was determined that the dispersibility of vanadium oxide had a significant effect on fast NH₃-SCR activity.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.259-263
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• 2008

The catalytic activity of the used catalyst, $V_2O_5/TiO_2$, for MSW incinerators was investigated focusing on its regeneration. As the result of the experimental analysis, the NOx removal efficiency difference between the fresh catalyst and used catalyst is about 60% at $260^{\circ}C$ and 1, 2-dichlorobenzen (1, 2-DCB) removal efficiency difference is about 14% at $200^{\circ}C$, in honeycomb test. And the catalysts, both the fresh and used, were characterized by XRD, TGA, and ICP techniques in order to investigate the deactivation. On the basis of the results, it is found that the used catalyst is deactivated by ammonium-sulfates, heavy metals (Pb, As etc.), alkali metals (Ca), and phase transfer of $TiO_2$. Also calcination treatment under nitrogen and air condition was excellent than washing and calcination treatment.

• Advances in concrete construction
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• v.7 no.2
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• pp.127-129
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• 2019

Heterogeneous photocatalysis is developed rapidly in the field of engineering of environmental. It has a good potential to tackle with the enhancing traffic pollution. Adding photocatalyst to usual building materials such as cement and concrete makes friendly environmental materials against the air pollution. TiO2 nanoparticles are a good item for concrete structures for diminishing the air polluting affect by gasses of exhaust. In specific, the transformation of NOx to NO3- is studied and the interaction of TiO2 nanoparticles and concrete is investigated here by experimental test. This paper presents an overview of the principle of photocatalysis and the application in combination with cement, as well as the results of the laboratory research, especially towards air purifying action. In addition, by the analytical models, the influence of TiO2 nanoparticles is studied on the stiffness of the concrete. The Results show that TiO2 nanoparticles have significant effect on the reduction of environmental pollution and increase of stiffness in the concrete structures.