Preparation and Characterization of MnOX-CeO2/TiO2 Catalytic Material for SCR of NOX with NH3 at Low Temperature

2013 ◽  
Vol 743-744 ◽  
pp. 198-203
Author(s):  
Qi Dong Liu ◽  
Su Ping Cui ◽  
Hong Xia Guo ◽  
Ya Li Wang ◽  
Yun Feng Zhang
Keyword(s):  
Low Temperature ◽  
Surface Concentration ◽  
Manganese Chloride ◽  
Molar Ratio ◽  
Manganese Acetate ◽  
Impregnation Method ◽  
Manganese Nitrate ◽  
Catalytic Materials ◽  
Scr Of No ◽  
Catalytic Material

The MnOX-CeO2/TiO2 catalytic material for low temperature SCR of NOX with NH3 was prepared using aqueous solutions of three manganese salt as well as cerous nitrate and TiO2(anatase) powder by impregnation method. The properties of the catalytic materials were investigated by TG-DSC, XRF, XRD, XPS, BET and SEM. And the low temperature catalytic activity of the catalytic materials was measured. The results showed that, when manganese nitrate and manganese chloride and manganese acetate were used as precursors, respectively, the primary phases of catalytic materials were MnOx/MnO2, MnO2/Mn8O10Cl3 and Mn3O4/MnO2, the surface Mn/Ti molar ratio were 0.68, 0.19 and 0.88, the surface area were 45.1m2/g, 25.1 m2/g and 48.6 m2/g ,respectively. The optimum NOX conversion rate of catalytic material from manganese nitrate precursor and manganese chloride precursor and manganese acetate precursor were 97.9% at 483K, 86.6% at 513K, 97.2% at 423K, respectively. Consequently, the higher low-temperature activity of MnOX-CeO2/TiO2 from manganese acetate precursor may be attributed to higher surface and higher surface concentration of activity component.

Experimental Study on Preparation and Operating Conditions over a Promising Monolithic Catalysts for NOx Removal: MnOx/TiO2/Cordierite

2017 ◽  
Vol 898 ◽  
pp. 1905-1915 ◽  
Author(s):  
Kai Qi ◽  
Jun Lin Xie ◽  
Feng Xiang Li ◽  
Feng He
Keyword(s):  
Low Temperature ◽  
Catalytic Reduction ◽  
Sol Gel ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Scope Of Application ◽  
Catalyst Dosage ◽  
Cordierite Honeycomb ◽  
Low Temperature Scr

The samples of MnOx/TiO2 catalysts supported on cordierite honeycomb ceramics were prepared by a sol-gel-impregnation method, and evaluated for low-temperature (353-473 K) selective catalytic reduction (SCR) of NOx with NH3. The influences of pretreatment on cordierite and catalyst dosage were investigated at first and optimized as follows: pickling for cordierite honeycomb ceramics with 1 mol/L HNO3 for 3 h prior to loading procedure as well as the catalyst dosage of 3-5 wt.%. The activity results indicated that there was an optimum working condition for MnOx/TiO2/cordierite catalysts: NH3/NO molar ratio=1.1, [O2]=3 vol.%, GHSV=5514 h-1, the highest activity of nearly 100% NO conversion could be obtained. As a comparison, the performances of commercialized vanadium-based honeycomb catalyst were also employed, which revealed the narrower scope of application of GHSV and the higher active temperature window. In conclusion, it turns out that the prepared MnOx/TiO2/cordierite catalysts are more applicable as a low-temperature SCR catalyst for NOx removal in a more complicated application environment.

scholarly journals Low Temperature NH3-SCR over Mn-Ce Oxides Supported on MCM-41 from Diatomite

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3654 ◽  
Author(s):  
Mingxuan Ma ◽  
Xiaoyu Ma ◽  
Suping Cui ◽  
Tingting Liu ◽  
Yingliang Tian ◽  
...  
Keyword(s):  
Molecular Sieves ◽  
Synthesis Method ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Catalyst Carrier ◽  
Nh3 Scr ◽  
Catalytic Material ◽  
Lewis Acidic Sites ◽  
Acidic Sites ◽  
Mcm 41

A series of MCM-41 molecular sieves with different molar ratio of template to silicon were synthesized through hydrothermal synthesis method by using cetyltrimethylammonium bromide (CTAB) as the template, diatomite as the silicon source. By using impregnation method, the Mn-Ce/MCM-41 SCR molecular sieve-based catalysts were prepared. The results observed that when the molar ratio of template to silicon was 0.2:1, the MCM-41 as catalyst carrier has the highest surface area and largest pore volume, it also presented typically ordered hexagonal arrays of uniform channels. The denitration catalytic material based on this carrier has a high number of Lewis acidic sites, and the denitration efficiency can reach more than 93%.

Studies on the Preparation and DeNOx Performance of MnxOy/CNTs Catalyst for Low-Temperature Selective Catalytic Reduction

2013 ◽  
Vol 798-799 ◽  
pp. 231-234 ◽  
Author(s):  
Bing Nan Ren ◽  
Qiao Wen Yang
Keyword(s):  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Oxide Catalyst ◽  
Catalytic Reduction ◽  
Space Velocity ◽  
Impregnation Method ◽  
Active Components ◽  
Reaction Conditions ◽  
No Conversion ◽  
Scr Of No

The metal oxide catalyst was prepared by loading MnxOyon carbon nanotubes (CNTs) with impregnation method. Then the catalyst was characterized by BET, TEM and XPS, and the catalytic activity of the catalyst for selective catalytic reduction (SCR) of NO at low-temperature was investigated. The results showed that the species of active components loaded on the catalyst were MnO2and Mn2O3. The NO conversion was improved with reduction temperature increase under 250°C, increased slowly over 250°C. The O2content had an outstanding effect on NO conversion of catalysts at a low concentration range. Once the oxygen content was enhanced over 5%, there was no significant increase in the NO conversion. With the increasing of space velocity, the NO conversion rate was decreased under the reaction conditions.

Synthesis of a novel highly dispersed manganese oxide on porous calcium silicate for catalytic oxidation of toluene

2022 ◽  
Author(s):  
ziqiang wang ◽  
zhifei hao ◽  
yinmin zhang ◽  
junmin sun ◽  
Yongfeng Zhang
Keyword(s):  
Manganese Oxide ◽  
Catalytic Oxidation ◽  
Calcium Silicate ◽  
Manganese Oxides ◽  
Manganese Acetate ◽  
Impregnation Method ◽  
Manganese Nitrate ◽  
Highly Dispersed

Herein, a series of novel porous calcium silicate (PCS)-supported manganese oxides (MnOx) catalysts are first prepared by impregnation method using three different manganese precursors (manganese acetate, manganese nitrate and manganese...

scholarly journals Catalytic Synthesis of Levulinate Esters over Zirconia and its Modified Forms Coated on Honeycomb Monoliths: Green Synthesis

2019 ◽  
Vol 31 (9) ◽  
pp. 1993-1999
Author(s):  
Reena Saritha Serrao ◽  
S.Z. Mohamed Shamshuddin ◽  
Joyce D'souza
Keyword(s):  
Levulinic Acid ◽  
Surface Characteristics ◽  
Cost Effective ◽  
Molar Ratio ◽  
Esterification Reaction ◽  
Catalytic Materials ◽  
Ethyl Levulinate ◽  
Catalytic Material ◽  
Reaction Performance ◽  
Modified Forms

A series of solid acid catalysts such as ZrO2, Mo(VI)/ZrO2 and W(VI)/ZrO2 have been coated on honeycomb monoliths as well as synthesized in the powder forms and used as catalytic materials for synthesis of ethyl levulinate from levulinic acid and ethanol. These solid acids were characterized by BET, NH3-TPD/n-butyl amine back titration, FTIR, PXRD and SEM techniques. Effects of various reaction parameters towards the reaction performance were studied. The performance of the catalyst was tested based on nature of the catalyst (honeycomb coated or powder form), reaction time (1 to 5 h), molar ratio (1:1 to 1:12 levulinic acid to ethanol) and reusability of the catalytic material. An excellent yield (86-88 %) of ethyl levulinate was obtained under optimized conditions. An attempt is made to correlate the activity of the catalysts in this esterification reaction with their surface characteristics. The honeycomb monoliths coated with zirconia and its modified forms were found to be ecofriendly, cost-effective and reusable catalytic materials compared to their powder forms.

Influence of Fe Doping on Ce-Mn/TiO2-ZrO2 Catalysts for Low-Temperature Selective Catalytic Reduction of NO

2014 ◽  
Vol 898 ◽  
pp. 447-451 ◽  
Author(s):  
Yun Xiao Teng ◽  
Cun Yi Song ◽  
Xi Ning Lu ◽  
Zhen Song Tong ◽  
Yu San Qin
Keyword(s):  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Sol Gel ◽  
Molar Ratio ◽  
Fe Doping ◽  
Reduction Of No ◽  
No Conversion ◽  
Scr Of No ◽  
Fe Catalysts

Fe-Ce-Mn catalysts loaded on TiO2-ZrO2materials were prepared by sol-gel method and then were investigated for low temperature selective catalytic reduction (SCR) of NO with NH3. It was found that the NO conversions over Fe-Ce-Mn/TiO2-ZrO2was slightly improved compared with that over Ce-Mn/TiO2-ZrO2. The results showed that 96% NO conversion was obtained over Fe-Ce-Mn/TiO2-ZrO2with the molar ratio of Fe/Mn=0.3. A comparative study of Fe-Ce-Mn/TiO2- ZrO2and Ce-Mn/TiO2-ZrO2for NO conversions at 140°C in the presence of H2O and SO2proved that Fe-Ce-Mn/TiO2-ZrO2exhibited higher resistance to H2O and SO2than that of without Fe catalysts. In addition, Fe-Ce-Mn/TiO2-ZrO2presented 90.49% NO conversion after cutting off the injection of SO2and H2O.

Preparation of MnOx/CNTs Catalyst by in-Situ Precipitation Method For Low-Temperature NO Reduction with NH3

2020 ◽  
Vol 16 ◽  
Author(s):  
Yanbing Zhang ◽  
Yingzan Chen ◽  
Jinhe Huang ◽  
Mingjie Ding ◽  
Xiaoyan Li ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Sodium Carbonate ◽  
Catalytic Reduction ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Surface Element ◽  
Manganese Acetate ◽  
Nh3 Scr

Background: V2O5–WO3(MoO3)/TiO2 catalyst, as the core of selective catalytic reduction of NO with NH3 (SCR) has some drawbacks, such as high working temperature window (300-400oC), the toxicity of V-based catalyst and so on. Therefore, development of the catalyst with better low temperature denitration catalyst and weaker toxicity is necessary. Objective: Highly dispersed MnOx/CNTs catalysts with excellent denitration activity at 80-180oC, and weaker toxicity of MnOx. It is worth noting that an in-situ precipitation method based on the reaction of manganese acetate and sodium carbonate, which is advantageous to the in-situ deposition of active component, and the catalytic activity. Methods: MnOx/CNTs catalysts with different Mn/C molar ratio were fabricated by in-situ precipitation method due to the reaction of manganese acetate and sodium carbonate. And the microstructure, crystalline property, the content of surface element, valence state, redox property, and catalytic activity was confirmed by FESEM, TEM, XRD, XPS, TPD, and fixedbed reactor. Results: The as-prepared MnOx/CNTs catalysts exhibit outstanding low temperature SCR activity. And the NO conversion of the optimum 1.2% MnOx/CNTs catalyst reached 57.4-89.2% at 80-180oC, which resulted from the amorphous MnOx catalysts, higher ratio of Mn4+/Mn3+ and OS/(OS+OL). Conclusion: MnOx/CNTs catalysts have been prepared by the in-situ precipitation method based on the reaction of manganese acetate and sodium carbonate. And the resultant MnOx/CNTs catalysts presented excellent low temperature denitration activity between 80oC and 180oC. Among them, the 1.2% MnOx/CNTs catalyst exhibited the first rate low temperature denitration activity, and the denitration activity attained 57.4-89.2%, which may be owing to the presence of the weakly crystalline or amorphous MnOx, higher ratio of Mn4+/Mn3+ and OS/(OS+OL).

Selective Catalytic Reduction of NOx on VCuMn/TiO2 at Middle-Low Temperature

2012 ◽  
Vol 550-553 ◽  
pp. 128-131
Author(s):  
Zhi Hang Chen ◽  
Zhi Xiong Tang ◽  
Chao Ping Cen ◽  
Huan Mu Zeng ◽  
Ding Sheng Chen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalytic Reduction ◽  
Space Velocity ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
Sulfur Resistance ◽  
X Ray ◽  
High Sulfur Content ◽  
Scr Of No ◽  
Low Temperature Scr

In this dissertation, combinatorial chemistry was adopted, and the activities of a series of VCuMn/TiO2catalysts prepared by impregnation method for middle-low temperature SCR of NOxwere evaluated. The activity datas showed that 2V2Cu8Mn/TiO2exhibited better activity. At 200 °C, above 70% NOxconversion were both obtained with a gas hourly space velocity of 60,000 h-1, and NOxconversion of 2V2Cu8Mn/TiO2reached nearly 100% at 275~325 °C. The X-ray diffraction characterization showed that the CuO and Mn2O3phases in VCuMn/TiO2catalysts were the main active site and with better SCR activity at middle-low temperature. In addition, sulfur-resistance of VCuMn/TiO2catalysts were investigated, NOxconversion on 2V2Cu8Mn/TiO2was above 60% at 250 °C after feeding SO2(600 ppm). It can be concluded that the modified VCu/TiO2catalyst by adding manganese obtained a good de-NOxactivity in a high sulfur content gas stream.

scholarly journals Insight into the Promoting Role of Er Modification on SO2 Resistance for NH3-SCR at Low Temperature over FeMn/TiO2 Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 618
Author(s):  
Huan Du ◽  
Zhitao Han ◽  
Xitian Wu ◽  
Chenglong Li ◽  
Yu Gao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalyst Surface ◽  
Impregnation Method ◽  
In Situ Drifts ◽  
Tio2 Catalyst ◽  
Nh3 Scr ◽  
Nh3 Adsorption ◽  
So2 Resistance ◽  
Fast Scr

Er-modified FeMn/TiO2 catalysts were prepared through the wet impregnation method, and their NH3-SCR activities were tested. The results showed that Er modification could obviously promote SO2 resistance of FeMn/TiO2 catalysts at a low temperature. The promoting effect and mechanism were explored in detail using various techniques, such as BET, XRD, H2-TPR, XPS, TG, and in-situ DRIFTS. The characterization results indicated that Er modification on FeMn/TiO2 catalysts could increase the Mn4+ concentration and surface chemisorbed labile oxygen ratio, which was favorable for NO oxidation to NO2, further accelerating low-temperature SCR activity through the “fast SCR” reaction. As fast SCR reaction could accelerate the consumption of adsorbed NH3 species, it would benefit to restrain the competitive adsorption of SO2 and limit the reaction between adsorbed SO2 and NH3 species. XPS results indicated that ammonium sulfates and Mn sulfates formed were found on Er-modified FeMn/TiO2 catalyst surface seemed much less than those on FeMn/TiO2 catalyst surface, suggested that Er modification was helpful for reducing the generation or deposition of sulfate salts on the catalyst surface. According to in-situ DRIFTS the results of, the presence of SO2 in feeding gas imposed a stronger impact on the NO adsorption than NH3 adsorption on Lewis acid sites of Er-modified FeMn/TiO2 catalysts, gradually making NH3-SCR reaction to proceed in E–R mechanism rather than L–H mechanism. DRIFTS.

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