scholarly journals Effects of V2O5 and WO3 loadings on the catalytic performance of V2O5-WO3/TiO2 catalyst for SCR of NO with NH3

2017 ◽  
Vol 19 (1) ◽  
pp. 160-166 ◽  
Keyword(s):  
Active Sites ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Spectra Analysis ◽  
Xps Spectra ◽  
Scr Of No ◽  
Morphology And Structure ◽  
Method Effects ◽  
Xrd Patterns

<p>V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalysts were fabricated by a simple impregnation method. Effects of V<sub>2</sub>O<sub>5</sub> and WO<sub>3</sub> loadings on the catalytic performance of V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2</sub> catalyst for selective catalytic reduction (SCR) of NO with NH<sub>3</sub> were investigated. Morphology and structure of the V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalysts were characterised by XRD, SEM, XPS, and N<sub>2</sub> adsorption techniques. The XRD patterns of the V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalyst are indexed to anatase-TiO<sub>2</sub>. XPS spectra analysis confirms that V, Ti, W and O species exist on the surface of V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalyst. V<sub>2</sub>O<sub>5</sub> species are the main active sites in the process of SCR reaction. Increasing V<sub>2</sub>O<sub>5</sub> loading in the V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalysts can improve their catalytic performance. Exceeding 2 wt%, the catalytic performance of V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalyst begins to decline because high V<sub>2</sub>O<sub>5</sub> loading on TiO<sub>2</sub> speeds up the growth of anatase grains, which leads to the loss of catalytic activity. Appropriate WO<sub>3</sub> species can significantly improve the catalytic performance of V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalysts. However, as the WO<sub>3 </sub>loadings reaches 6 wt%, NO conversion decreases instead.</p>

Activity of yFe-10Cu/H-Sep and xCu/H-Sep for the Selective Catalytic Reduction of NO with Propylene

2012 ◽  
Vol 518-523 ◽  
pp. 281-284
Author(s):  
Qing Ye ◽  
Hai Ping Wang ◽  
Hai Xia Zhao ◽  
Shui Yuan Cheng ◽  
Tian Fang Kang
Keyword(s):  
Catalytic Reduction ◽  
Catalytic Performance ◽  
High Dispersion ◽  
High Catalytic Activity ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Promotional Effect ◽  
Scr Of No ◽  
Metal Support Interaction ◽  
Metal Support

Cu supported on acid-treated sepiolite catalysts (xCu/H-Sep, x = 0  20.0 wt%) or Cu-Fe mixed supported on acid-treated sepiolite catalysts (yFe-10Cu/H-Sep, y = 0  20.0 wt%) were prepared by the incipient wetness impregnation method. The xCu/H-Sep and yFe-10Cu/H-Sep catalysts were characterized by means of XRD, BET, XRF, XPS, and H2-TPR techniques, and their catalytic activities were evaluated for the SCR of NO with propylene. XPS and XRD results indicate that there was the co-presence of Cu+-Cu2+ and Fe2+-Fe3+ over the surfaces of yFe-10Cu/H-Sep catalysts, and there was a strong interaction between Cu, Fe and sepiolite. High promotional effect of iron additive on the catalytic performance of Cu/H-Sep catalyst were found in C3H6-SCR of NO reaction. The highest activity of 65% NO conversion was obtained over 15Fe-10Cu/H-Sep catalyst at 280 oC under the condition of 1000 ppm NO, 1000 ppm C3H6, and 5% O2. The high catalytic activity of 15Fe-10Cu/H-Sep catalyst for NO reduction was due to its high reducibility to activate C3H6 to selectively reduce NO in the presence of excess O2. The high dispersion of copper oxides and strong metal-support interaction over 15Fe-10Cu/H-Sep catalyst also improve its catalytic performance.

scholarly journals Effect of Transition Metal Additives on the Catalytic Performance of Cu–Mn/SAPO-34 for Selective Catalytic Reduction of NO with NH3 at Low Temperature

Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 685
Author(s):  
Guofu Liu ◽  
Wenjie Zhang ◽  
Pengfei He ◽  
Dekui Shen ◽  
Chunfei Wu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metal Oxides ◽  
Active Sites ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Decomposition Temperature ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
Before And After ◽  
So2 Resistance

The adsorption of NO, NH3, H2O, and SO2 gaseous molecules on different transition metal oxides was studied based on density function theory (DFT), and three better-performing transition metal elements (Fe, Co, and Ce) were selected. Cu–Mn/SAPO-34 catalysts were prepared by impregnation method and then modified by the selected transition metals (Fe, Co, and Ce); the SO2 resistance experiments and characterizations including Brunner−Emmet−Teller (BET), X-ray Diffraction (XRD), Scanning Electronic Microscopy (SEM), and thermal gravity analysis (TG)-differential thermal gravity (DTG) before and after SO2 poisoning were conducted. The results showed that the deactivation of the Cu–Mn/SAPO-34 catalyst is ascribed to the deposition of lots of ammonium sulfates on the surface, depositing on the active sites and inhibiting the adsorption of NH3. After the modification of Fe, Co, and Ce oxides, the SO2 resistance of the modified Cu–Mn/SAPO-34 catalyst was significantly enhanced due to the less formation of ammonium sulfates. Among all these modified Cu–Mn/SAPO-34 catalysts, the Cu–Mn–Ce/SAPO-34 exhibited the highest SO2 resistance owing to the decreased decomposition temperature and the trapper of ceria for capturing SO2 to form Ce(SO4)2, further inhibiting the deposition of ammonium sulfates.

scholarly journals Improved SO2 Tolerance of Cu-SAPO-18 by Ce-Doping in the Selective Catalytic Reduction of NO with NH3

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 783
Author(s):  
Shuai Han ◽  
Qing Ye ◽  
Qi Gao ◽  
Hongxing Dai
Keyword(s):  
Selective Catalytic Reduction ◽  
Active Sites ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Sulfur Poisoning ◽  
Remarkable Change ◽  
Exchange Method ◽  
Scr Of No ◽  
Catalytic Active Sites ◽  
The Impact

The Ce-Cu-SAPO-18 catalysts were prepared using the ion exchange method. The impact of sulfur dioxide on catalytic performance of Ce-Cu-SAPO-18 for the selective catalytic reduction (SCR) of NO with NH3 was examined. Detailed characterization of the fresh and sulfur-poisoning Cu-SAPO-18 and Ce-Cu-SAPO-18 samples was conducted. XRD and BET results show that SO2 treatment of the Ce-doped Cu-SAPO-18 (Ce-Cu-SAPO-18-S) sample did not induce a remarkable change in structure, as compared with that of the fresh counterpart. According to in situ DRIFT, H2-TPR, SEM, and EDS results, it is found that the sulfation species attached preferentially to the cerium species, rather than the isolated Cu2+ species. In particular, the TG/DSC results confirm that the sulfate species on the Ce-Cu-SAPO-18-S sample was easier to decompose than that on the Cu-SAPO-18-S sample. The catalytic active sites of Ce-Cu-SAPO-18 were less influenced after SO2 treatment, as demonstrated by the TPR and XPS results. All of the above results show that the Ce-Cu-SAPO-18 sample exhibited better sulfur-resistant performance than the Cu-SAPO-18 sample.

CuO Supportd Ce-Ti Mixed Oxides for Low-Temperature SCR of NO with Propene

2012 ◽  
Vol 518-523 ◽  
pp. 2456-2459 ◽  
Author(s):  
Jie Liu ◽  
Xin Yong Li ◽  
Qi Dong Zhao ◽  
Dong Ke Zhang
Keyword(s):  
Mixed Oxides ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Bet Surface Area ◽  
Precipitation Method ◽  
Catalyst Characterization ◽  
Impregnation Method ◽  
Composite Catalysts ◽  
Scr Of No ◽  
Low Temperature Scr

CuO/TiO2, CuO/Ti0.9Ce0.1O2 and CuO/CeO2/TiO2 composite catalysts were prepared and tested for their application in selective catalytic reduction (SCR) of NO with C3H6. The effect of CeO2 species on the catalytic performance was further evaluated. Catalyst characterization including BET surface area, XRD and temperature-programmed reduction of H2 (H2-TPR) suggested that the addition of CeO2 species changed the physicochemical properties of the catalysts obtained. Compared to the impregnation method, the homogeneous precipitation method was an effective approach to preparing the CeO2 doped catalyst, which could promote the activation of C3H6 to react with NO.

Research of Catalytic Performance over Transition Metal Modified MnOx-CeOx/ACF Catalysts

2011 ◽  
Vol 383-390 ◽  
pp. 1945-1950 ◽  
Author(s):  
Bo Xiong Shen ◽  
Ting Liu ◽  
Ning Zhao ◽  
Juan Ma ◽  
Xiao Cui Hao
Keyword(s):  
Catalytic Activity ◽  
Thermal Treatment ◽  
Transition Metal ◽  
Catalytic Reduction ◽  
Surface Acidity ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Active Components ◽  
Scr Of No ◽  
Negative Effect

The catalyst of MnOx-CeOx/ACF prepared by impregnation method was used for low-temperature selective catalytic reduction (SCR) of NO with NH3, and more than 90% NO conversion was obtained at 230°C. Fe、Cu or V was used respectively to prepare transition metal modified MnOx-CeOx/ ACF catalysts which had lower catalytic activity than that over MnOx-CeOx/ACF. SEM, N2 adsorption and NH3-TPD were used to analyze the catalysts. The results showed that transition metal modified catalysts had a reduced surface area, pore volume and surface acidity. SO2 had a negative effect on SCR performance of the catalysts. Fe modified catalyst exhibited SO2 tolerance in the first 6h in the presence of 100ppm SO2. Thermal treatment in N2 at 350°C was used to regenerate the deactivated catalysts by SO2. The decomposition of ammonium salts recovered the catalytic activity to some extent. The sulfated active components in deactivated catalysts after the thermal treatment enhanced the surface acidity of the catalysts.

Structural/Texture Evolution During Facile Substitution of Ni into ZSM-5 Nanostructure vs. its Impregnation Dispersion Used in Selective Transformation of Methanol to Ethylene and Propylene

2020 ◽  
Vol 23 ◽  
Author(s):  
Parisa Sadeghpour ◽  
Mohammad Haghighi ◽  
Mehrdad Esmaeili
Keyword(s):  
High Temperature ◽  
Physicochemical Properties ◽  
Active Sites ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Light Olefins ◽  
Isomorphous Substitution ◽  
Impregnation Method ◽  
Hydrothermal Temperature ◽  
X Ray

Aim and Objective: Effect of two different modification methods for introducing Ni into ZSM-5 framework was investigated under high temperature synthesis conditions. The nickel successfully introduced into the MFI structures at different crystallization conditions to enhance the physicochemical properties and catalytic performance. Materials and Methods: A series of impregnated Ni/ZSM-5 and isomorphous substituted NiZSM-5 nanostructure catalysts were prepared hydrothermally at different high temperatures and within short times. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray (EDX), Brunner, Emmett and Teller-Barrett, Joyner and Halenda (BET-BJH), Fourier transform infrared (FTIR) and Temperature-programmed desorption of ammonia (TPDNH3) were applied to investigate the physicochemical properties. Results: Although all the catalysts showed pure silica MFI–type nanosheets and coffin-like morphology, using the isomorphous substitution for Ni incorporation into the ZSM-5 framework led to the formation of materials with lower crystallinity, higher pore volume and stronger acidity compared to using impregnation method. Moreover, it was found that raising the hydrothermal temperature increased the crystallinity and enhanced more uniform incorporation of Ni atoms in the crystalline structure of catalysts. TPD-NH3 analysis demonstrated that high crystallization temperature and short crystallization time of NiZSM-5(350-0.5) resulted in fewer weak acid sites and medium acid strength. The MTO catalytic performance was tested in a fixed bed reactor at 460ºC and GHSV=10500 cm3 /gcat.h. A slightly different reaction pathway was proposed for the production of light olefins over impregnated Ni/ZSM-5 catalysts based on the role of NiO species. The enhanced methanol conversion for isomorphous substituted NiZSM-5 catalysts could be related to the most accessible active sites located inside the pores. Conclusion: The impregnated Ni/ZSM-5 catalyst prepared at low hydrothermal temperature showed the best catalytic performance, while the isomorphous substituted NiZSM-5 prepared at high temperature was found to be the active molecular sieve regarding the stability performance.

scholarly journals Novel Preparation of Cu and Fe Zirconia Supported Catalysts for Selective Catalytic Reduction of NO with NH3

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 55
Author(s):  
Katarzyna Świrk ◽  
Ye Wang ◽  
Changwei Hu ◽  
Li Li ◽  
Patrick Da Costa ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Supported Catalysts ◽  
Catalytic Performance ◽  
Experimental Conditions ◽  
One Pot ◽  
Nh3 Scr ◽  
Scr Of No ◽  
Temperature Programmed ◽  
Stationary Sources

Copper and iron promoted ZrO2 catalysts were prepared by one-pot synthesis using urea. The studied catalysts were characterized by XRD, N2 physisorption, XPS, temperature-programmed desorption of NH3 (NH3-TPD), and tested by the selective catalytic reduction by ammonia (NH3-SCR) of NO in the absence and presence of water vapor, under the experimental conditions representative of exhaust gases from stationary sources. The influence of SO2 on catalytic performance was also investigated. Among the studied catalysts, the Fe-Zr sample showed the most promising results in NH3-SCR, being active and highly selective to N2. The addition of SO2 markedly improved NO and NH3 conversions during NH3-SCR in the presence of H2O. The improvement in acidic surface properties is believed to be the cause.

scholarly journals Catalytic Activity Of Cu/η-Al2O3 Catalysts Prepared From Aluminum Scraps In The NH3-SCO and in the NH3-SCR of NO

2021 ◽  
Author(s):  
Nawel Jr ◽  
Thabet Makhlouf ◽  
Gerard Delahay ◽  
Hassib Tounsi
Keyword(s):  
Catalytic Oxidation ◽  
Catalytic Reduction ◽  
Impregnation Method ◽  
Wet Impregnation ◽  
Reduction Of No ◽  
Evaporation Method ◽  
Nh3 Scr ◽  
Scr Of No ◽  
Selective Catalytic Oxidation ◽  
Wet Impregnation Method

Abstract Copper loaded η-alumina catalysts with different copper contents have been prepared by impregnation/evaporation method. The catalysts were characterized by XRD, FTIR, BET, UV–vis, H2-TPR and evaluated in the selective catalytic reduction of NO by NH3 and in the selective catalytic oxidation of NH3. The characterization techniques showed that the impregnation/evaporation method permits to obtain highly dispersed copper oxide species on the η-alumina surface when low amount of copper is used (1wt. % and 2 wt.%). The wet impregnation method made it possible to reach a well dispersion of the copper species on the surface of the alumina for the low copper contents Cu(1)-Al2O3 and Cu(2)-Al2O3. The latter justifies the similar behavior of Cu(1)-Al2O3) and Cu(2)-Al2O3 in the selective catalytic oxidation of NH3 where these catalysts exhibit a conversion of NH3 to N2 of the order of 100% at T > 500°C.

Cu-Supported on Sodium-Treated Sepiolite for Selective Catalytic Reduction of NO by Propylene

2015 ◽  
Vol 1088 ◽  
pp. 569-572
Author(s):  
Zhi Hao Zhang ◽  
Yang Li ◽  
Yun Fang Qi ◽  
Qing Ye ◽  
Shu Lan Ji ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
High Performance ◽  
Catalytic Reduction ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Redox Species ◽  
Reduction Of No ◽  
Catalytic Activities ◽  
Scr Of No ◽  
Activity Center

Cu/Na-Sep samples were prepared by the incipient wetness impregnation method. These catalysts were characterized by means of XRF, XRD, and XPS techniques, and their catalytic activities were performed by the SCR of NO with propylene. The results show that the Cu/Na-Sep catalyst exhibited the high performance in the C3H6-SCR of NO. After investigation by XRD and XPS, the result showed that there are Cu2+/Cu+redox species as a reaction activity center over Cu/Na-Sep.

scholarly journals Physicochemical and Catalytic Properties of Vanadia/Titania Catalysts. V. Selective Catalytic Reduction of NO with NH3

2002 ◽  
Vol 20 (10) ◽  
pp. 937-945
Author(s):  
Th. El-Nabarawy ◽  
M.N. Alaya ◽  
S.A. Sayed Ahmed ◽  
A.M. Youssef
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Properties ◽  
Catalytic Reduction ◽  
Impregnation Method ◽  
Reduction Of No ◽  
No Conversion ◽  
Scr Of No ◽  
Monolayer Coverage

Vanadia/titania catalysts were prepared containing 6.0 or 8.0 wt% V2O5 via the impregnation method. The samples as prepared were calcined at 400°C or 600°C, respectively. Selective catalytic reduction (SCR) of NO with NH3 was carried out at 257°C over the prepared catalysts. NO conversion as a function of time was followed and the stationary conversion versus the amount of catalyst employed was also investigated. It was found that the vanadia/titania catalysts calcined at 400°C were more active in the SCR of NO with NH3 relative to those calcined at 600°C. This was attributed to such catalysts possessing complete monolayer coverage of vanadia on the titania substrate. It was established that V5+ was not the active vanadia species but V4+ and V3+ may act as such for the SCR of NO with NH3.

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