scholarly journals Morphology and Crystal-Plane Effects of Fe/W-CeO2 for Selective Catalytic Reduction of NO with NH3

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 288 ◽  
Author(s):  
Feihu Liu ◽  
Zhong Wang ◽  
Da Wang ◽  
Dan Chen ◽  
Fushan Chen ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Hydrothermal Method ◽  
Surface Area ◽  
Conversion Rate ◽  
Oxygen Vacancies ◽  
Catalytic Reduction ◽  
Acid Sites ◽  
Crystal Surfaces ◽  
Reduction Of No ◽  
No Conversion

The CeO2 ordinary amorphous, nanopolyhedrons, nanorods, and nanocubes were prefabricated by the hydrothermal method, and employed as carriers of Fe/W–CeO2 catalysts to selectively catalyze the reduction of NO with ammonia. Characterization results indicated that the morphology of CeO2 support originated from selectively exposing different crystal surfaces, which has a significant effect on oxygen vacancies, acid sites and the dispersion of Fe2O3. The CeO2 nanopolyhedrons catalyst (Fe/W–CeO2–P) showed most oxygen vacancies, the largest the quantity of acid sites, the largest BET (Brunauer-Emmett-Teller) surface area and the best dispersion of Fe2O3, which was associated with predominately exposing CeO2 (111) planes. Consequently, the Fe/W–CeO2–P catalyst has the highest NO conversion rate in the temperature range of 100–325 °C among the ordinary amorphous, nanorods, and nanocubes Fe/W–CeO2 catalysts.

V2O5-WO3/TiO2 Catalysts for Low Temperature NH3 SCR: Catalytic Activity and Characterization

2016 ◽  
Vol 697 ◽  
pp. 275-278 ◽  
Author(s):  
Yu Xin Deng ◽  
Xin Chen ◽  
Rong Shao ◽  
Li Ming Hu ◽  
Jie Tang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Surface Area ◽  
Catalytic Reduction ◽  
Anatase Phase ◽  
Systematic Investigation ◽  
Acid Sites ◽  
Bet Surface Area ◽  
Reduction Of No

A systematic investigation of the effect of WO3 loading over V2O5/TiO2 catalysts was carried out for the selective catalytic reduction of NO by NH3. The characteristics were examined use BET surface area , X-ray diffractometry (XRD) , Temperature programmed desorption (TPD) of NH3 . It was fund that the WO3 species could interact with the TiO2 anatase phase to exhibits a high activity. With increasing WO3 content ,the activity of V-W/TiO2 for the selective catalytic reduction of NO by NH3 was improved at low temperatures in the range of 3～7%. The results showed that the adding of WO3 to V2O5/TiO2 could result in exposing acid sites of catalysts doped WO3 at low temperature. Furthermore, especially the catalytic activity of VW7Ti showed higher than 80% at 180 °C. However, the catalytic BET surface area and the mass of acid sites not play a leading role for improving low-temperature activity of VWTi in this paper.

A Ce-Zr-Ti Oxide Catalyst for Selective Catalytic Reduction of NO with Ammonia

2014 ◽  
Vol 535 ◽  
pp. 709-712
Author(s):  
Ye Jiang ◽  
Yan Yan ◽  
Shan Bo Huang ◽  
Xiong Zhang ◽  
Xin Wei Wang ◽  
...  
Keyword(s):  
High Activity ◽  
Selective Catalytic Reduction ◽  
Oxide Catalyst ◽  
Catalytic Reduction ◽  
Space Velocity ◽  
Impregnation Method ◽  
Reduction Of No ◽  
No Conversion ◽  
Temperature Range ◽  
Ti Oxides

A Ce-Zr-Ti oxide catalyst was prepared by an impregnation method and tested for the selective catalytic reduction of NO with NH3. The Ce-Zr-Ti oxide catalyst exhibited high activity and more than 95% NO conversion was obtained within the temperature range 300-500 °C at the high gas hourly space velocity of 50,000 h-1. The addition of Zr improved the activity of Ce-Ti oxides especially at higher reaction temperatures and their resistance to SO2.

Efficiency of Phosphotungstic Acid Modified Mn-Based Catalysts to Promote Activity and N2 Formation for Selective Catalytic Reduction of NO with Ammonia

2019 ◽  
Vol 17 (7) ◽  
Author(s):  
Yongqiang Huang ◽  
Peixin Li ◽  
Runduo Zhang ◽  
Ying Wei
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Acid Sites ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brønsted Acid Sites ◽  
No Conversion ◽  
Brönsted Acid ◽  
Brönsted Acid Sites ◽  
Nitrate Species

Abstract In this work, the modified Mn-based NH3-SCR (NH3 low-temperature selective catalytic reduction) catalysts with excellent NO conversion and N2 selectivity be designed. N2 yield was hardly more than 75 % over MnOx/TiO2 for NH3-SCR reaction, whereas the NH3-SCR performance has been significantly improved by using 50 wt.% HPW (H3PW12O40)-MnOx/TiO2. 100 % NO conversion and more than 95 % N2 yield was obtained in wide operating temperature window (150–400°C), suggesting that the addition of HPW could effectively improve the NO reduction conversion. After that, the catalysts were further characterized by XRD, H2-TPR, XPS and in situ DRIFT. DRIFT analysis implied that the introduction of HPW significantly improve the capacity of NH4 + species adsorbed on Brønsted acid sites accompanied with inhibiting the formation and consumption of nitrite species. It proved that the non-selective catalytic reduction reaction over HPW-MnOx/TiO2 catalysts are restrained. HPW could accelerate the formation and consumption of NH4 + species adsorbed on Brønsted acid sites with deactivation of nitrate species. In addition, NH3(ad) could be hardly oxidized to NH species and then reacted with nitrate species (L-H mechanism) and gaseous NO (E-R mechanism). More importantly, the oxidation of NH3 was also suppressed, which plays a dominate role to form N2O above 300°C. Besides, the deactivation of potassium poisoning on the SCR activity significantly weakened for modified samples compared to parent catalyst.

Highly dispersed Fe2O3 on carbon nanotubes for low-temperature selective catalytic reduction of NO with NH3

2015 ◽  
Vol 51 (5) ◽  
pp. 956-958 ◽  
Author(s):  
Zhenping Qu ◽  
Lei Miao ◽  
Hui Wang ◽  
Qiang Fu
Keyword(s):  
Carbon Nanotubes ◽  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Low Temperatures ◽  
Catalytic Reduction ◽  
Reduction Of No ◽  
No Conversion ◽  
Highly Dispersed

Highly dispersed Fe2O3 nanoparticles supported on CNTs showed excellent NO conversion, selectivity and durability towards SO2/H2O at low temperatures (200–325 °C).

Low Temperature Selective Catalytic Reduction of NO on CeO2-Fe3O4/TiO2,CeO2 /TiO2 Catalysts Prepared by Coprecipitation Method

2014 ◽  
Vol 960-961 ◽  
pp. 234-239 ◽  
Author(s):  
Wen Long Zhen ◽  
Rui Tang Guo ◽  
Wei Guo Pan
Keyword(s):  
Low Temperature ◽  
Adsorption Capacity ◽  
Selective Catalytic Reduction ◽  
Surface Area ◽  
Catalytic Reduction ◽  
Coprecipitation Method ◽  
High Concentration ◽  
Excellent Performance ◽  
Reduction Of No ◽  
Chemisorbed Oxygen

CeO2-Fe3O4/TiO2and CeO2/TiO2catalysts were prepared by coprecipitation method, and their activities for selective catalytic reduction of NO with NH3were investigated. As can be seen from the experimental results, the CeO2-Fe3O4/TiO2catalyst prepared showed the best SCR activity and SO2resistance. Based on the characterization results of BET, XRD, NH3-TPD and XPS the excellent performance of CeO2-Fe3O4/TiO2catalyst should be resulted from its large surface area, high NH3adsorption capacity and high concentration of surface chemisorbed oxygen.

Synthesis, characterization and catalytic performances of Cu- and Mn-containing ordered mesoporous carbons for the selective catalytic reduction of NO with NH3

2015 ◽  
Vol 5 (2) ◽  
pp. 1267-1279 ◽  
Author(s):  
Feifei Cao ◽  
Jinghuan Chen ◽  
Changlei Lyu ◽  
Mingjiang Ni ◽  
Xiang Gao ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Effect ◽  
Catalytic Reduction ◽  
Mesoporous Carbons ◽  
Ordered Mesoporous Carbons ◽  
Reduction Of No ◽  
No Conversion ◽  
Ordered Mesoporous ◽  
Catalytic Performances

The synergetic catalytic effect of Cu and Mn for CuxMny-OMCs catalysts on NO conversion with NH3.

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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