Effect of hierarchical element doping on the low-temperature activity of manganese-based catalysts for NH3-SCR

Tang, Xiaolong; Wang, Chengzhi; Gao, Feifei; Ma, Yanmei; Yi, Honghong; Zhao, Shunzheng; Zhou, You

doi:10.1016/j.jece.2020.104399

Cited by 66 publications

(32 citation statements)

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“…A higher amount of Cu 2+ was beneficial for a low-temperature catalytic activity, so that 5% Mn/Cu-SSZ-13 performed better [26]. Furthermore, the Mn 2p spectra of 5% Mn/Cu-SSZ-13 are presented in Figure S5b, and the binding energy values at 655.3 eV and 643.2 eV were assigned to Mn 2p 1/2 and Mn 2p 3/2, respectively [26,27,39]. To calculate the composition of Mn ions, the peak around 650~640 eV was deconvoluted; the contents of Mn 2+ , Mn 3+ and Mn 4+ ions were 17.9%, 62.3% and 19.8%, respectively.…”

Section: Characterization Of Catalystsmentioning

confidence: 97%

“…As presented in Figure S5a, the binding energy values of Cu 2p 1/2 and Cu 2p 3/2 were 953.9 eV and 934.0 eV in both catalysts, respectively. Meanwhile, there were satellite peaks around 965~962 eV and 941~949 eV in 5% Mn/Cu-SSZ-13; however, no satellite peaks were observed in Cu-SSZ-13 [26,27]. Through the deconvolution of the peak with a binding energy of around 940~930 eV, the composition of Cu ions with different valence states was calculated.…”

Section: Characterization Of Catalystsmentioning

confidence: 99%

“…To calculate the composition of Mn ions, the peak around 650~640 eV was deconvoluted; the contents of Mn 2+ , Mn 3+ and Mn 4+ ions were 17.9%, 62.3% and 19.8%, respectively. As a result, in addition to there being more Cu 2+ ions in 5% Mn/Cu-SSZ-13, another reason why Mn-impregnated catalysts performed better in the low-temperature range was the presence of a large amount of Mn 3+ and Mn 4+ ions [26,27,39].…”

Section: Characterization Of Catalystsmentioning

confidence: 99%

“…Numerous studies showed that, at temperatures below 180 • C, Mn-based catalysts were very active in the NH 3 -SCR reaction [21][22][23][24][25][26][27]. For instance, over 90% NO x conversion could be obtained over MnO x -CeO 2 complex oxide catalysts at 150 • C [21,28].…”

Section: Introductionmentioning

confidence: 99%

“…Tang et al doped a series of metals on Mn-based catalysts, and they found that the Mn-Fe-Ce catalyst performed the best. A 95% NO x conversion could be obtained, and it also had an excellent SO 2 and H 2 O tolerance [27]. Ye et al synthesized a series of Mn/SSZ-13 catalysts with various Mn loadings, and over 95% NO x conversion was obtained at 150 • C for the best sample [29].…”

Section: Introductionmentioning

confidence: 99%

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Promoting Effect of Mn on In Situ Synthesized Cu-SSZ-13 for NH3-SCR

Wang

Shi

et al. 2020

Catalysts

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The effect of Mn impregnation on the NH3-SCR (selective catalytic reduction of NOx by NH3) activity of in situ synthesized Cu-SSZ-13 was investigated in this work. It was found that Mn addition could efficiently improve the low-temperature activity of Cu-SSZ-13. The optimal amount of Mn was 5 wt.%, and NOx conversion was improved by more than 20% over a temperature range of 120 °C to 150 °C. SEM (scanning electron microscopy), XRD (X-ray diffraction), N2 adsorption-desorption, H2-TPR (temperature programmed reduction of H2), NH3-TPD (temperature programmed desorption of NH3) and in situ DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) experiments were conducted to investigate the changes in the zeolite structure, active sites, acid sites and reaction mechanism. The impregnated MnOx species caused a decline in the crystallinity of Cu-SSZ-13 but markedly improved the redox ability. Nitrate and nitrite species were observed in the Mn-modified Cu-SSZ-13, and the formation of these species was thought to cause the observed increase in low-temperature NH3-SCR activity. The results show that the addition of Mn is a promising method for promoting the low-temperature catalytic activity of Cu-SSZ-13.

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Section: Characterization Of Catalystsmentioning

confidence: 97%

Section: Characterization Of Catalystsmentioning

confidence: 99%

Section: Characterization Of Catalystsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Promoting Effect of Mn on In Situ Synthesized Cu-SSZ-13 for NH3-SCR

Wang

Shi

et al. 2020

Catalysts

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Activity Test and Mechanism Study of 3DOM Ce_0.8M_0.1Zr_0.1O₂ (M=Cr, Sn, Fe, Co, Ni, Mn, Cu) Catalyst in the Selective Catalytic Reduction of NO by CO**

Liu

Líu

et al. 2021

ChemCatChem

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The results show that the NO conversion rate of 3DOM Ce 0.8 Cu 0.1 Zr 0.1 O 2 catalyst at a lower temperature (150 °C) is close to 60 %. Besides, 3DOM Ce 0.8 Cu 0.1 Zr 0.1 O 2 kept a stable NO removal efficiency within a wide range of gas hourly space velocity (GHSV) and long reaction time and exhibited remarkable resistance to H 2 O and SO 2 poisoning, both individually and simultaneously. At the same time, the formation of the 3DOM structure not only improves the reduction performance and surface active sites of the catalyst, but also forms more oxygen defects and Ce 3 + in the catalyst due to the strong synergistic effect of metal ions and ceria, which improves the surface oxygen concentration of the composite oxide catalyst and further improves the catalytic activity. In addition, the doping of copper ions on the surface of the 3DOM Cu-CZ catalyst can improve the activity of the catalyst and it can get trapped by CO to form Cu + -CO, which plays an important role in the NO + CO reaction at low temperature. The existence of oxygen vacancy at high temperature is beneficial to the activation of O 2 and the dissociation of NO in the process of CO oxidation. The reaction of NO + CO over 3DOM Cu-CZ catalyst follows LÀ H and EÀ R mechanism respectively.

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The optimization of hydrothermal synthesis of Mn_xCo_3‐xO₄/GC catalyst for low temperature NH₃‐SCR /using design of experiments

Tang

Gao

et al. 2021

J of Chemical Tech & Biotech

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BACKGROUND In this study, a new catalyst for low‐temperature selective catalytic reduction of NOx with NH3 (NH3‐SCR) were prepared by using glucose and discussed optimization of the synthetic conditions of MnxCo3−xO4/GC (glucose carbon) catalysts by using the design of the experiments. A response surface methodology (RSM) combined with the central composite design (CCD) was applied to model and optimize the synthetic conditions. RESULTS As a result, the optimum NOx conversion of 95.6% and N2 selectivity of 81.8% were obtained at Mn/Co 2.1, urea/(Mn + Co) mole ratio 11.5, glucose/(Mn + Co) mole ratio 8.9, preparation temperature 175.4 °normalC, and calcination temperature 376.3 °normalC. The SEM (Scanning electron microscope) image and EDS (Energy Dispersive Spectroscopy) analysis showed that metal oxides of Mn and Co were uniformly accumulated on the carbon microsphere surface. XRD (X‐ray diffraction) patterns showed that CoCo2O4 content in the catalyst increased with the increase of the glucose/(Mn + Co) mole ratio, which reduced the interaction between Mn and Co, and played a negative impact on catalytic performance. FTIR (Fourier‐transform infrared) spectra showed that the catalyst surface in the optimum preparation conditions had more oxygen‐containing functional groups and that the excessive glucose carbon was unfavourable to catalytic performance. For urea/(Mn + Co), as urea/(Mn + Co) decreased, in addition to the decrease in Mn and Co content in the catalyst due to the decrease in precipitant, CoCo2O4 content in the catalyst also increased and oxygen‐containing functional groups decreased, both of which resulted in the decrease of the catalytic performance. CONCLUSION The H2‐TPR and NH3‐TPD results demonstrated that the catalyst prepared in the optimum conditions possessed a stronger reducing ability, more acid sites, and stronger acid strength than the other. © 2021 Society of Chemical Industry

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Effect of hierarchical element doping on the low-temperature activity of manganese-based catalysts for NH3-SCR

Cited by 66 publications

References 50 publications

Promoting Effect of Mn on In Situ Synthesized Cu-SSZ-13 for NH3-SCR

Promoting Effect of Mn on In Situ Synthesized Cu-SSZ-13 for NH3-SCR

Activity Test and Mechanism Study of 3DOM Ce_0.8M_0.1Zr_0.1O₂ (M=Cr, Sn, Fe, Co, Ni, Mn, Cu) Catalyst in the Selective Catalytic Reduction of NO by CO**

The optimization of hydrothermal synthesis of Mn_xCo_3‐xO₄/GC catalyst for low temperature NH₃‐SCR /using design of experiments

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Effect of hierarchical element doping on the low-temperature activity of manganese-based catalysts for NH3-SCR

Cited by 66 publications

References 50 publications

Promoting Effect of Mn on In Situ Synthesized Cu-SSZ-13 for NH3-SCR

Promoting Effect of Mn on In Situ Synthesized Cu-SSZ-13 for NH3-SCR

Activity Test and Mechanism Study of 3DOM Ce0.8M0.1Zr0.1O2 (M=Cr, Sn, Fe, Co, Ni, Mn, Cu) Catalyst in the Selective Catalytic Reduction of NO by CO**

The optimization of hydrothermal synthesis of MnxCo3‐xO4/GC catalyst for low temperature NH3‐SCR /using design of experiments

Contact Info

Product

Resources

About

Activity Test and Mechanism Study of 3DOM Ce_0.8M_0.1Zr_0.1O₂ (M=Cr, Sn, Fe, Co, Ni, Mn, Cu) Catalyst in the Selective Catalytic Reduction of NO by CO**

The optimization of hydrothermal synthesis of Mn_xCo_3‐xO₄/GC catalyst for low temperature NH₃‐SCR /using design of experiments