scholarly journals Promotional Effect on Selective Catalytic Reduction of NOxwith NH3over Overloaded W and Ce on V2O5/TiO2Catalysts

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Seunghee Youn ◽  
Inhak Song ◽  
Do Heui Kim
Keyword(s):  
High Temperature ◽  
Selective Catalytic Reduction ◽  
Temperature Region ◽  
Catalytic Reduction ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
High Temperature Region ◽  
Promotional Effect ◽  
Temperature Programmed ◽  
Adsorption Desorption

W and Ce are known to be a good promoters to improve selective catalytic reduction (SCR) activity for V2O5/TiO2catalysts. This work aimed at finding the optimum ratio and loading of promoters (W and Ce) on V2O5/TiO2catalyst in order to improve SCR reactivity in low temperature region and to minimize N2O formation in high temperature region. In addition, we changed the order of impregnation between W and Ce precursors on V2O5/TiO2catalyst during the preparation and observed its effect on SCR activity and N2selectivity. We utilized various analytical techniques, such as N2adsorption-desorption, X-ray diffraction (XRD), and temperature-programmed reduction with hydrogen (H2TPR) to investigate the physicochemical properties of catalysts. It was found that W- and Ce-overloaded V2O5/TiO2catalyst such as W/Ce/V/TiO2(15 : 15 : 1 wt%) showed the most remarkable DeNOxproperties over the wide temperature region. Additionally, this catalyst significantly suppressed N2O formation during SCR reaction, especially in high temperature region (350–400°C). Based on the characterization results, it was found that such superior activity originated from the improved reducibility and morphology of W and Ce species on V2O5/TiO2catalyst when they are incorporated together at high loading.

Promotion Effects of Metal Oxides on the Ag/Al2O3 Catalysts for Selective Catalytic Reduction of NO with C3H6

2012 ◽  
Vol 550-553 ◽  
pp. 214-219 ◽  
Author(s):  
Xin Yu Shi ◽  
Yan Yang ◽  
Zhi Dou Tan
Keyword(s):  
Metal Oxide ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Earth Metal ◽  
X Ray Diffraction ◽  
Alumina Support ◽  
Reduction Of No ◽  
Temperature Programmed ◽  
Xrd Techniques ◽  
Adsorption Desorption

The transition-metal oxide(ZrO2, Fe2O3) and rare earth-metal oxide(La2O3, CeO2) promoted Ag/Al2O3 catalysts for selective catalytic reduction of NO by C3H6 were investigated. These catalysts were characterized by temperature programmed desorption of NO and O2 (NO-TPD and O2-TPD), N2 adsorption/desorption isotherms (BET), and X-ray diffraction (XRD) techniques, respectively. The BET result indicates the ZrO2 promoted sample possesses larger surface area, and the TPD analysis demonstrates the dispersity and amount of adsorbed NO and O2 are improved, both the results are favorable for the catalytic activity, which can be attributed to the synergic interaction between zirconia promoter and alumina support shown in the XRD pattern.

Selective catalytic reduction of NO by Co-Mn based nanocatalysts

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vahid Zabihi ◽  
Mohammad Hasan Eikani ◽  
Mehdi Ardjmand ◽  
Seyed Mahdi Latifi ◽  
Alireza Salehirad
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Energy Dispersive ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Techniques ◽  
Acidic Sites ◽  
Temperature Window ◽  
Temperature Programmed

Abstract One of the most significant aspects in selective catalytic reduction (SCR) of nitrogen oxides (NOx) is developing suitable catalysts by which the process occurs in a favorable way. At the present work SCR reaction by ammonia (NH3-SCR) was conducted using Co-Mn spinel and its composite with Fe-Mn spinel, as nanocatalysts. The nanocatalysts were fabricated through liquid routes and then their physicochemical properties such as phase composition, degree of agglomeration, particle size distribution, specific surface area and also surface acidic sites have been investigated by X-ray diffraction, Field Emission Scanning Electron Microscope, Energy-dispersive X-ray spectroscopy, energy dispersive spectroscopy mapping, Brunauer–Emmett–Teller, temperature-programmed reduction (H2-TPR) and temperature-programmed desorption of ammonia (NH3-TPD) analysis techniques. The catalytic activity tests in a temperature window of 150–400 °C and gas hourly space velocities of 10,000, 18,000 and 30,000 h−1 revealed that almost in all studied conditions, CoMn2O4/FeMn2O4 nanocomposite exhibited better performance in SCR reaction than CoMn2O4 spinel.

scholarly journals Nanosized V-Ce Oxides Supported on TiO2 as a Superior Catalyst for the Selective Catalytic Reduction of NO

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 202
Author(s):  
Long Lu ◽  
Xueman Wang ◽  
Chunhua Hu ◽  
Ying Liu ◽  
Xiongbo Chen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Photoelectron Spectroscopy ◽  
Catalytic Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Redox Capacity ◽  
Scr Of No ◽  
Temperature Programmed

Nanosized V-Ce oxides supported on TiO2 (VCT) were prepared and utilized in the low-temperature selective catalytic reduction (SCR) of NO with NH3. Compared with the other V-Ce oxides-based catalysts supported on Al2O3, ZrO2, and ZSM-5, VCT showed the best SCR activity in a low-temperature range. The NOx conversion of 90% could be achieved at 220 °C. Characterizations including X-ray diffraction (XRD), scanning election micrograph (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption with NH3 (NH3-TPD), and temperature-programmed reduction with H2 (H2-TPR) showed that V1.05Ce1/TiO2 exhibited a good dispersion of V2O5, enrichment of surface Ce3+ and chemical-absorbed oxygen, and excellent redox capacity and acidity, which resulted in the best SCR performance at low temperature.

scholarly journals Promotional Effect of Cerium and/or Zirconium Doping on Cu/ZSM-5 Catalysts for Selective Catalytic Reduction of NO by NH3

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 306 ◽  
Author(s):  
Ye Liu ◽  
Chonglin Song ◽  
Gang Lv ◽  
Chenyang Fan ◽  
Xiaodong Li
Keyword(s):  
Selective Catalytic Reduction ◽  
Photoelectron Spectroscopy ◽  
Catalytic Reduction ◽  
Copper Ions ◽  
N2o Formation ◽  
Copper Species ◽  
X Ray ◽  
Promotional Effect ◽  
Zirconium Doping ◽  
Temperature Programmed

The cerium and/or zirconium-doped Cu/ZSM-5 catalysts (CuCexZr1−xOy/ZSM-5) were prepared by ion exchange and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction by hydrogen (H2-TPR). Activities of the catalysts obtained on the selective catalytic reduction (SCR) of nitric oxide (NO) by ammonia were measured using temperature programmed reactions. Among all the catalysts tested, the CuCe0.75Zr0.25Oy/ZSM-5 catalyst presented the highest catalytic activity for the removal of NO, corresponding to the broadest active window of 175–468 °C. The cerium and zirconium addition enhanced the activity of catalysts, and the cerium-rich catalysts exhibited more excellent SCR activities as compared to the zirconium-rich catalysts. XRD and TEM results indicated that zirconium additions improved the copper dispersion and prevented copper crystallization. According to XPS and H2-TPR analysis, copper species were enriched on the ZSM-5 grain surfaces, and part of the copper ions were incorporated into the zirconium and/or cerium lattice. The strong interaction between copper species and cerium/zirconium improved the redox abilities of catalysts. Furthermore, the introduction of zirconium abates N2O formation in the tested temperature range.

Effect of the Addition of In to Co/HMCM-49 Catalyst for the Selective Catalytic Reduction of NO Under Lean-burn Conditions

2010 ◽  
Vol 224 (06) ◽  
pp. 907-920 ◽  
Author(s):  
Fei Li ◽  
Dehai Xiao ◽  
Jing Li ◽  
Xiangguang Yang
Keyword(s):  
Selective Catalytic Reduction ◽  
Wide Temperature Range ◽  
Catalytic Reduction ◽  
Temperature Programmed Desorption ◽  
X Ray Diffraction ◽  
Lean Burn ◽  
Reduction Of No ◽  
X Ray ◽  
Scr Of No ◽  
Temperature Programmed

AbstractSelective catalytic reduction (SCR) of NO with propane using bimetals (3Co2Ce, 3Co2Sr, 3Co2Sn and 3Co2In) loaded on HMCM-49 zeolite was studied under lean-burn condition. Only 3Co2In/HMCM-49 exhibited higher deNOx activity in a wide temperature range. The catalysts were characterized by N2-adsoption, X-ray diffraction (XRD), temperature-programmed surface reactions (TPSR) and temperature-programmed desorption (TPD) of NO. TPSR and TPD results exhibited that the addition of In inhibited the oxidation ability of Co on 3Co2In/HMCM-49 catalyst, but enhanced NOx adsorption.

Basicity and Crystal Phase of Mesoporous K2O-MgO/ZrO2-La2O3 Catalyst

2014 ◽  
Vol 924 ◽  
pp. 269-274
Author(s):  
Yu Su ◽  
Guo Jun Dong ◽  
Cheng Yuan Wang ◽  
Jin Sheng Gao ◽  
Dong Sheng Ma ◽  
...  
Keyword(s):  
High Temperature ◽  
Monoclinic Phase ◽  
Dimethyl Carbonate ◽  
Catalyst Surface ◽  
Temperature Programmed Desorption ◽  
Solid Base ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Adsorption Desorption

A new solid base, mesoporous K2O-MgO/ZrO2-La2O3, was prepared by hydrothermal and immersion process using a cationic surfactant C16H33(CH3)3NBr (CTAB) as template．The samples were characterized by N2 adsorption-desorption, X-ray diffraction(XRD), Raman spectroscope and CO2 temperature programmed desorption(CO2-TPD). XRD and Raman spectra indicated that the catalyst calcined at 600°C and 700 °C remained surface and bulk tetragonal phase and good mesoporous characteristics when the content of K2O is less than 0.5. While the monoclinic phase is appeared on catalyst surface when the content of K2O is more than 0.5 calcined at 700 °C. CO2-TPD proves that there are two adsorption states at high temperature corresponding to super alkaline sites of K2O and undecomposed KNO3. The catalyst with 0.4 mol ratio of K2O to ZrO2 calcined at 700 °C showed higher activity in the synthesis of di-2-ethylhexyl carbonate (DEHC) from dimethyl carbonate (DMC) and 2-ethylhexanol (EHOH).

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 Fe2O3 enhanced high-temperature arsenic resistance of CeO2–La2O3/TiO2 catalyst for selective catalytic reduction of NOx with NH3

RSC Advances ◽  
2021 ◽  
Vol 11 (16) ◽  
pp. 9395-9402
Author(s):  
Na Wang ◽  
Changfei Ye ◽  
Huidong Xie ◽  
Chang Yang ◽  
Jinhong Zhou ◽  
...  
Keyword(s):  
High Temperature ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Arsenic Resistance ◽  
No Conversion ◽  
Tio2 Catalyst ◽  
Reduction Of Nox ◽  
Better Than

The NO conversion of the CeLa0.5Fe0.2/Ti is obviously better than that of the commercial vanadium-based catalyst with regard to arsenic resistance and it has good N2 selectivity, and good SO2 resistance.

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