scholarly journals Improvement of low-temperature NH3-SCR catalytic performance over nitrogen-doped MOx–Cr2O3–La2O3/TiO2–N (M = Cu, Fe, Ce) catalysts

RSC Advances ◽  
2021 ◽  
Vol 11 (37) ◽  
pp. 22780-22788
Author(s):  
Xiaoyi Sun ◽  
Qingjie Liu ◽  
Shuai Liu ◽  
Xintang Zhang ◽  
Shanshan Liu
Keyword(s):  
Low Temperature ◽  
Nitrogen Doping ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Nitrogen Doped ◽  
Nh3 Scr

A series of MOx–Cr2O3–La2O3/TiO2–N (M = Cu, Fe, Ce) catalysts with nitrogen doping were prepared via the 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.

CeMn/TiO2 catalysts prepared by different methods for enhanced low-temperature NH3-SCR catalytic performance

2021 ◽  
pp. 116588
Author(s):  
Xianlong Zhang ◽  
Xincheng Zhang ◽  
Xiangjin Yang ◽  
Yazhong Chen ◽  
Xiaorui Hu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalytic Performance ◽  
Nh3 Scr

scholarly journals Catalytic Performance of Nitrogen-Doped Activated Carbon Supported Pd Catalyst for Hydrodechlorination of 2,4-Dichlorophenol or Chloropentafluoroethane

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 674 ◽  
Author(s):  
Haodong Tang ◽  
Bin Xu ◽  
Meng Xiang ◽  
Xinxin Chen ◽  
Yao Wang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Liquid Phase ◽  
Gas Phase ◽  
Nitrogen Doping ◽  
Catalyst Surface ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Pd Catalyst ◽  
Nitrogen Doped ◽  
The Stability

Nitrogen-doped activated carbon (N-AC) obtained through the thermal treatment of a mixture of HNO3-pretreated activated carbon (AC) and urea under N2 atmosphere at 600 °C was used as the carrier of Pd catalyst for both liquid-phase hydrodechlorination of 2,4-dichlorophenol (2,4-DCP) and gas-phase hydrodechlorination of chloropentafluoroethane (R-115). The effects of nitrogen doping on the dispersion and stability of Pd, atomic ratio of Pd/Pd2+ on the surface of the catalyzer, the catalyst’s hydrodechlorination activity, as well as the stability of N species in two different reaction systems were investigated. Our results suggest that, despite no improvement in the dispersion of Pd, nitrogen doping may significantly raise the atomic ratio of Pd/Pd2+ on the catalyst surface, with a value of 1.2 on Pd/AC but 2.2 on Pd/N-AC. Three types of N species, namely graphitic, pyridinic, and pyrrolic nitrogen, were observed on the surface of Pd/N-AC, and graphitic nitrogen was stable in both liquid-phase hydrodechlorination of 2,4-DCP and gas-phase hydrodechlorination of R-115, with pyridinic and pyrrolic nitrogen being unstable during gas-phase hydrodechlorination of R-115. As a result, the average size of Pd nanocrystals on Pd/N-AC was almost kept unchanged after liquid-phase hydrodechlorination of 2,4-DCP, whereas crystal growth of Pd was clearly observed on Pd/N-AC after gas-phase hydrodechlorination of R-115. The activity test revealed that Pd/N-AC exhibited a much better performance than Pd/AC in liquid-phase hydrodechlorination of 2,4-DCP, probably due to the enhanced stability of Pd exposed to the environment resulting from nitrogen doping as suggested by the higher atomic ratio of Pd/Pd2+ on the catalyst surface. In the gas-phase hydrodechlorination of R-115, however, a more rapid deactivation phenomenon occurred on Pd/N-AC than on Pd/AC despite a higher activity initially observed on Pd/N-AC, hinting that the stability of pyridinic and pyrrolic nitrogen plays an important role in the determination of catalytic performance of Pd/N-AC.

Synergistic effect of VOx and MnOx surface species for improved performance of V2O5/Ce0.5Ti0.5−xMnxO2−δ catalysts in low-temperature NH3-SCR of NO

2018 ◽  
Vol 8 (24) ◽  
pp. 6360-6374 ◽  
Author(s):  
Thanh Huyen Vuong ◽  
Stephan Bartling ◽  
Ursula Bentrup ◽  
Henrik Lund ◽  
Jabor Rabeah ◽  
...  
Keyword(s):  
Low Temperature ◽  
Synergistic Effect ◽  
Catalytic Performance ◽  
Surface Species ◽  
Nh3 Scr ◽  
Redox Couples ◽  
Scr Of No ◽  
Improved Performance

Inserting adjacent Mn3+/Mn2+ and VO3+/VO2+ redox couples in Ce1−xTixO2 improves catalytic performance.

scholarly journals The Effect of Tourmaline on SCR Denitrification Activity of MnOx/TiO2 at Low Temperature

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1020
Author(s):  
Yizhe Helian ◽  
Suping Cui ◽  
Xiaoyu Ma
Keyword(s):  
Low Temperature ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Scr Catalyst ◽  
Highly Efficient ◽  
Nh3 Scr ◽  
Catalytic Material ◽  
Acidic Sites ◽  
Denitrification Activity ◽  
The Stability

Selective catalytic reduction (SCR) technology is the most widely used flue gas denitration technology at present. The stability of a catalyst is the main factor limiting the development of this technology. In this study, an environmentally friendly and highly efficient NH3-SCR catalyst was prepared by coprecipitation method from acidolysis residue of industrial waste and tourmaline. We found that the addition of tourmaline has an important impact on the denitration activity of the catalytic material. The NOx conversion exceeded 97% at 200 °C with the dosage of 10% tourmaline, which is about 7% higher than that without doping. The improvement of catalytic performance was mostly attributed to the permanent electrodes of tourmaline, which effectively promotes the dispersion of MnOx/TiO2 catalytic materials, increases the number of acidic sites and changes the valence distribution of manganese ions in products, which speeds up the diffusion of protons and ions, resulting in the acceleration of redox reaction. These as-developed tourmaline-modified MnOx/TiO2 materials have been demonstrated to be promising as a new type of highly efficient low-temperature NH3-SCR catalyst.

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.

A Highly Effective Catalyst of Sm-MnOx for the NH3-SCR of NOx at Low Temperature: Promotional Role of Sm and Its Catalytic Performance

ACS Catalysis ◽  
2015 ◽  
Vol 5 (10) ◽  
pp. 5973-5983 ◽  
Author(s):  
Dongmei Meng ◽  
Wangcheng Zhan ◽  
Yun Guo ◽  
Yanglong Guo ◽  
Li Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalytic Performance ◽  
Effective Catalyst ◽  
Nh3 Scr ◽  
Highly Effective ◽  
Scr Of Nox

scholarly journals Promotional effects of nitrogen doping on catalytic performance over manganese-containing semi-coke catalysts for the NH3-SCR at low temperatures

2020 ◽  
Vol 387 ◽  
pp. 121704 ◽  
Author(s):  
Lu Yao ◽  
Qingcai Liu ◽  
Susanne Mossin ◽  
David Nielsen ◽  
Ming Kong ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Nitrogen Doping ◽  
Catalytic Performance ◽  
Nh3 Scr

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.

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