scholarly journals The Influence of Ce or Mn Doping on Cu-Based Catalysts for De-NOx with NH3-SCR

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Lei Jiang ◽  
Yixi Cai ◽  
Miaomiao Jin ◽  
Zengzan Zhu ◽  
Yinhuan Wang
Keyword(s):  
Low Temperature ◽  
Physicochemical Properties ◽  
Topological Structure ◽  
Zeolite Catalysts ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Performance Tests ◽  
Nh3 Scr ◽  
Temperature Window ◽  
Different Doses

In this study, the de-NOx performance of Cu-based zeolite catalysts supported on topological structure (SSZ-13, BEA, ZSM-5) and loaded with different doses of copper (from 2 to 6 wt.%) was investigated. The preparation of copper-based catalysts adopted the incipient wetness impregnation method. To analyze the physicochemical properties of the catalysts, advanced techniques like BET, XRD, NH3-TPD, H2-TPR, and DRS UV-Vis were used. The performance tests suggested the 4Cu/SSZ-13 catalyst exhibited higher low-temperature activity and wider temperature window. Furthermore, compared with Mn-Cu/SSZ-13, the Ce-Cu/SSZ-13 catalysts exhibited better de-NOx performance.

scholarly journals Catalytic Performances of Cu/MCM-22 Zeolites with Different Cu Loadings in NH3-SCR

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2170
Author(s):  
Jialing Chen ◽  
Gang Peng ◽  
Tingyu Liang ◽  
Wenbo Zhang ◽  
Wei Zheng ◽  
...  
Keyword(s):  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Hydrothermal Aging ◽  
Copper Species ◽  
Cu Content ◽  
Nh3 Scr ◽  
Water Vapor Atmosphere ◽  
Pore Blockage ◽  
Temperature Window ◽  
Catalytic Performances

The NH3-SCR activities and hydrothermal stabilities of five xCu/MCM-22 zeolites with different Cu loadings (x = 2–10 wt%) prepared by incipient wetness impregnation method were systematically investigated. The physicochemical properties of xCu/MCM-22 zeolites were analyzed by XRD, nitrogen physisorption, ICP-AES, SEM, NH3-TPD, UV-vis, H2-TPR and XPS experiments. The Cu species existing in xCu/MCM-22 are mainly isolated Cu2+, CuOx and unreducible copper species. The concentrations of both isolated Cu2+ and CuOx species in xCu/MCM-22 increase with Cu contents, but the increment of CuOx species is more distinct, especially in high Cu loadings (>4 wt%). NH3-SCR experimental results demonstrated that the activity of xCu/MCM-22 is sensitive to Cu content at low Cu loadings (≤4 wt%). When the Cu loading exceeds 4 wt%, the NH3-SCR activity of xCu/MCM-22 is irrelevant to Cu content due to the severe pore blockage effects caused by aggregated CuOx species. Among the five xCu/MCM-22 zeolites, 4Cu/MCM-22 with moderate Cu content has the best NH3-SCR performance, which displays higher than 80% NOx conversions in a wide temperature window (160–430 °C). Furthermore, the hydrothermal aging experiments (xCu/MCM-22 was treated at 750 °C for 10 h under 10% water vapor atmosphere) illustrated that all the xCu/MCM-22 zeolites exhibit high hydrothermal stability in NH3-SCR reactions.

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.

Effect of Supports on the Properties of Co-Mo Nitride Catalysts for Ammonia Decomposition

2011 ◽  
Vol 391-392 ◽  
pp. 1215-1219 ◽  
Author(s):  
Zhao Hui Zhao ◽  
Han Bo Zou ◽  
Wei Ming Lin
Keyword(s):  
Elevated Temperatures ◽  
Active Species ◽  
Ammonia Decomposition ◽  
Zeolite Catalysts ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
5A Zeolite ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction ◽  
Effect Of Support

Supported Co–Mo nitride catalysts have been synthesized by incipient-wetness impregnation method and temperature-programmed reaction in N2-H2 mixed gases. The effect of support types, namely carbon nanotubes(CNTs), active carbon(AC), 5A zeolite and Al2O3 on the properties of the prepared catalysts for ammonia decomposition has been investigated by XRD, H2–TPR and SEM techniques. The results showed that CNTs was the optimum support for Co–Mo nitride catalyst. At 550 , NH3 conversions over CoMoNx/AC, CoMoNx/Al2O3 and CoMoNx/5A Zeolite catalysts were only 14.7%, 65.4% and 68.7%, respectively, while NH3 conversion over CoMoNx/CNTs catalyst was up to 84.4%. XRD and H2–TPR results indicated that the active species consist of CoMoO4, MoO3, γ-Mo2N and Co3Mo3N crystallites, which can be reduced at elevated temperatures at H2 atmosphere. The SEM characterization demonstrated that Co-Mo nitrides particles disperse uniformly on the CNTs.

Highly water-resistant carbon nanotube supported PdCl2–CuCl2 catalysts for low temperature CO oxidation

RSC Advances ◽  
2016 ◽  
Vol 6 (71) ◽  
pp. 66553-66563 ◽  
Author(s):  
Fanyun Zhou ◽  
Xuexun Du ◽  
Jun Yu ◽  
Dongsen Mao ◽  
Guanzhong Lu
Keyword(s):  
Carbon Nanotube ◽  
Low Temperature ◽  
Physicochemical Properties ◽  
Co Oxidation ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Low Temperature Co Oxidation

PdCl2–CuCl2/CNT was prepared by the two-step impregnation method, and the effects of the Pd and Cu loadings on its physicochemical properties and catalytic performance for low-temperature CO oxidation in the presence of H2O were investigated.

scholarly journals Co3O4/g-C3N4 Hybrids for Gas-Phase Hg0 Removal at Low Temperature

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 279 ◽  
Author(s):  
Zhen Zhang ◽  
Jiang Wu ◽  
Dongjing Liu
Keyword(s):  
Electron Transfer ◽  
Low Temperature ◽  
Gas Phase ◽  
Cobalt Oxide ◽  
Cooperative Effect ◽  
Side Reactions ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Interfacial Contact ◽  
Mercury Capture

The Co3O4/g-C3N4 hybrids are constructed via the incipient wetness impregnation method by depositing Co3O4 onto the exterior of g-C3N4, and then employed for Hg0 capture within 60–240 °C. The results show that the Co3O4/g-C3N4 hybrid with a Co3O4 content of 12 wt% performs optimally with the highest Hg0 removal efficiency of ~100% at or above 120 °C. The high performances of the Co3O4/g-C3N4 hybrids are probably attributed to the tight interfacial contact between Co3O4 and g-C3N4, with its improved electron transfer, inferring that cobalt oxide and g-C3N4 display a cooperative effect towards Hg0 removal. NO and SO2 shows a significant suppressive influence on the mercury capture performance, plausibly owing to the competing adsorption and side reactions.

Understanding the nature of NH3-coordinated active sites and the complete reaction schemes for NH3-SCR using Cu-SAPO-34 catalysts

2021 ◽  
Author(s):  
Guangpeng Yang ◽  
Jingyu Ran ◽  
Xuesen Du ◽  
Xiangmin Wang ◽  
Zhilin Ran ◽  
...  
Keyword(s):  
Low Temperature ◽  
Active Sites ◽  
Zeolite Catalysts ◽  
Copper Species ◽  
Nh3 Scr ◽  
Complete Reaction ◽  
Catalytic Capacity ◽  
Reaction Schemes

Cu-SAPO-34 zeolite catalysts show excellent NH3-SCR performance at low temperature, which is due to the catalytic capacity of copper species.

scholarly journals Effect of the NH4NO3 Addition on the Low-T NH3-SCR Performances of Individual and Combined Fe- and Cu-Zeolite Catalysts

2019 ◽  
Vol 5 (4) ◽  
pp. 290-296 ◽  
Author(s):  
R. Villamaina ◽  
I. Nova ◽  
E. Tronconi ◽  
T. Maunula ◽  
M. Keenan
Keyword(s):  
Low Temperature ◽  
Ammonium Nitrate ◽  
Zeolite Catalysts ◽  
Feed Stream ◽  
Combined System ◽  
Zeolite Sample ◽  
Nh3 Scr ◽  
The Poor ◽  
Fast Scr ◽  
Standard Scr

Abstract We have measured NOx conversions and N2O productions over Fe-BEA and Cu-SAPO catalysts and over their sequential arrangements under Enhanced SCR conditions, resulting from the addition of an aqueous solution of ammonium nitrate (AN) to the typical Standard SCR feed stream, and we have compared them to those observed under Standard and Fast SCR conditions. The expected strong enhancement of the poor low temperature activity of the Fe-BEA catalyst was confirmed: both NH3 and NOx conversions and N2O formations similar to those of the Fast SCR reaction were achieved when cofeeding ammonium nitrate. On the other hand, the Cu-SAPO efficiency was drastically decreased by the addition of AN at low temperatures, possibly due to trapping of the ammonium nitrate salt within the SAPO zeolite, characterized by smaller pores than those of the BEA zeolite. The Cu-SAPO performances were recovered only at T > 250 °C with a huge release of N2O due to the thermal decomposition of AN. The combined system with the Fe-zeolite sample placed upstream of the Cu-zeolite also exhibited outstanding low temperature deNOx performances, with even lower N2O production than over the Fe-zeolite only at the same Enhanced SCR (E-SCR) conditions.

scholarly journals Preparation and Characterization of Ni/ZrTiAlOx Catalyst via Sol-Gel and Impregnation Methods for Low Temperature Dry Reforming of Methane

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1335
Author(s):  
Seol A Shin ◽  
Ali Alizadeh Eslami ◽  
Young Su Noh ◽  
Hyun-tae Song ◽  
Hyun Dong Kim ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Sol Gel ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Ternary Metal ◽  
Inhibition Property ◽  
Diffuse Reflectance Infrared

Recently, the dry reforming of methane (DRM) has received much attention as a conversion technology of greenhouse gases. Ni-based catalysts supported on ternary metal oxide composite (ZrTiAlOx) were prepared to improve the coke resistance properties in the DRM (CH4:CO2 = 1) at low temperature. The ZrTiAlOx supports with different ratios of Zr/Ti were prepared through the modified Pechini sol-gel method, and then the Ni was impregnated on the synthesized support via the incipient wetness impregnation method. Considering the Zr/Ti ratios, different catalytic activity and durability in the DRM were identified. The Ni/ZrTiAlOx catalyst with Zr/Ti of 2 exhibited enhanced coke inhibition property compared to the others at low temperature DRM for 50 h. The catalysts with a high Zr/Ti ratio under the same condition were rapidly deactivated, while the catalyst with a low Zr/Ti ratio showed deficient activity. It was found from temperature-programmed surface reactions (TPSR) and DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) analysis that the addition of Ti has led in to higher catalytic stability at Zr/Ti = 2, which could be as a result of oxygen vacancies generated by the ternary metal oxides. Ni/ZrTiAlOx catalyst with ratio of Zr/Ti = 2 showed high stability and good catalytic activity towards DRM for the production of syngas.

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