A novel strategy for constructing mesoporous solid superbase catalysts: bimetallic Al–La oxides supported on SBA-15 modified with KF

2017 ◽  
Vol 7 (3) ◽  
pp. 725-733 ◽  
Author(s):  
Ning Liu ◽  
Zhimin Wu ◽  
Meng Li ◽  
Shanshan Li ◽  
Yongfei Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Potassium Fluoride ◽  
Impregnation Method ◽  
Novel Strategy ◽  
Solid Superbase

Bimetallic Al–La oxides were conjointly precoated on SBA-15 prior to the introduction of potassium fluoride to achieve solid superbases at low temperature by a modified wetness impregnation method.

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.

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 CO Oxidation over Metal Oxide (La2O3, Fe2O3, PrO2, Sm2O3, and MnO2) Doped CuO-Based Catalysts Supported on Mesoporous Ce0.8Zr0.2O2 with Intensified Low-Temperature Activity

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 724 ◽  
Author(s):  
Yan Cui ◽  
Leilei Xu ◽  
Mindong Chen ◽  
Chufei Lv ◽  
Xinbo Lian ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Metal Oxide ◽  
Metal Oxides ◽  
Co Oxidation ◽  
Active Sites ◽  
Earth Metal ◽  
High Dispersion ◽  
Impregnation Method ◽  
X Ray

CuO-based catalysts are usually used for CO oxidation owing to their low cost and excellent catalytic activities. In this study, a series of metal oxide (La2O3, Fe2O3, PrO2, Sm2O3, and MnO2)-doped CuO-based catalysts with mesoporous Ce0.8Zr0.2O2 support were simply prepared by the incipient impregnation method and used directly as catalysts for CO catalytic oxidation. These mesoporous catalysts were systematically characterized by X-ray powder diffraction (XRD), N2 physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS), and H2 temperature programmed reduction (H2-TPR). It was found that the CuO and the dopants were highly dispersed among the mesoporous framework via the incipient impregnation method, and the strong metal framework interaction had been formed. The effects of the types of the dopants and the loading amounts of the dopants on the low-temperature catalytic performances were carefully studied. It was concluded that doped transition metal oxides could regulate the oxygen mobility and reduction ability of catalysts, further improving the catalytic activity. It was also found that the high dispersion of rare earth metal oxides (PrO2, Sm2O3) was able to prevent the thermal sintering and aggregation of CuO-based catalysts during the process of calcination. In addition, their presence also evidently improved the reducibility and significantly reduced the particle size of the CuO active sites for CO oxidation. The results demonstrated that the 15CuO-3Fe2O3/M-Ce80Zr20 catalyst with 3 wt. % of Fe2O3 showed the best low-temperature catalytic activity toward CO oxidation. Overall, the present Fe2O3-doped CuO-based catalysts with mesoporous nanocrystalline Ce0.8Zr0.2O2 solid solution as support were considered a promising series of catalysts for low-temperature CO oxidation.

Preparation of Ni/ZrO2/SiO2 Catalyst and its Application in Hydrogenation of CO2 to Methane

2020 ◽  
Vol 1001 ◽  
pp. 79-83
Author(s):  
Zhen Xing Han ◽  
Si Xi Guo ◽  
Kai Ming Li ◽  
Bing Yao ◽  
Ming Song ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Catalytic Performance ◽  
Experimental Results ◽  
Impregnation Method ◽  
Energy And Environment ◽  
Supported Ni ◽  
Hydrogenation Of Co

The hydrogenation of CO2 to CH4 can realize the utilization of CO2, which has an important implications to both the energy and environment. As a result of the low catalytic activity of the supported Ni/SiO2 catalyst, the ZrO2 is added to improve its catalytic performance by the impregnation method. The experimental results show that ZrO2 is an effective promoter to enhance the low-temperature catalytic activity of Ni/SiO2 catalyst.

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.

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 Novel strategy for low-temperature, high-rate growth of dense, hard, and stress-free refractory ceramic thin films

2014 ◽  
Vol 32 (4) ◽  
pp. 041515 ◽  
Author(s):  
Grzegorz Greczynski ◽  
Jun Lu ◽  
Stephan Bolz ◽  
Werner Kölker ◽  
Christoph Schiffers ◽  
...  
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
High Rate ◽  
Ceramic Thin Films ◽  
Refractory Ceramic ◽  
Novel Strategy

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.

Double Negative Property in Co/YIG Prepared by Low Temperature Impregnation Process

2015 ◽  
Vol 816 ◽  
pp. 107-112 ◽  
Author(s):  
Xu Ai Wang ◽  
Run Hua Fan ◽  
Zhi Cheng Shi ◽  
Min Chen ◽  
Ke Lan Yan ◽  
...  
Keyword(s):  
Low Temperature ◽  
Three Dimensional ◽  
Cobalt Content ◽  
Electromagnetic Properties ◽  
Microwave Antenna ◽  
Impregnation Method ◽  
Double Negative ◽  
Impedance Analyzer ◽  
Traveling Wave Tubes ◽  
Stealth Materials

Impregnation method was used for fabricating Co/YIG (Y3Fe5O12) composites under low temperature, and the electromagnetic properties were tuned by adjusting the content (0 wt% - 35 wt%) and microstructure of the metal in composites. The XRD and SEM were used to analyze the phase and microstructure. Electromagnetism properties including reactance, permittivity and permeability of the composites were tested using impedance analyzer (10 MHz~1 GHz). The results indicated that, the high cobalt content leads to the formation of three-dimensional cobalt networks on the pore walls of porous YIG gradually, and their electromagnetic properties have also been changed significantly with the Co content increasing. Especially, double negative properties were achieved in Co/YIG composites when the content of Co reached 35 wt% at the frequency band of 575 MHz-1 GHz. The appearance of double negative properties in cermets provides promising applications in electromagnetic stealth materials, microwave antenna, and traveling wave tubes.

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