scholarly journals Insight into Platinum Poisoning Effect on Cu-SSZ-13 in Selective Catalytic Reduction of NOx with NH3

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 796
Author(s):  
Huawang Zhao ◽  
Lei Han ◽  
Yujie Wang ◽  
Jiandong Zheng
Keyword(s):  
Catalytic Reduction ◽  
No Oxidation ◽  
Oxidation Reactions ◽  
Hydrothermal Aging ◽  
N2o Formation ◽  
Poisoning Effect ◽  
Nh3 Oxidation ◽  
Reduction Of Nox ◽  
Parallel Reactions ◽  
Insight Into

Platinum’s (Pt) poisoning effect on Cu-SSZ-13 and its regeneration were investigated. The Pt enhanced the parallel reactions, such as NH3 oxidation and NO oxidation reactions, which decreased the deNOx activities. In the temperature range below 330 °C, the deactivation of Cu-SSZ-13 by Pt poisoning was primarily caused by the overconsumption of NH3, due to the enhanced NH3-selective oxidation reaction, while the formation of NOx in NH3 oxidation and NO oxidation into NO2 further aggravated the degradation when the temperature was above 460 °C. The non-selective NH3 oxidation and non-selective NOx catalytic reduction reactions resulted in increased N2O formation over Pt-doped samples. The transformation of Pt0 into PtOx after hydrothermal aging recovered the deNOx activities of the Pt-poisoned samples.

Insight into the Potassium Poisoning Effect for Selective Catalytic Reduction of NOx with NH3 over Fe/Beta

ACS Catalysis ◽  
2021 ◽  
pp. 14727-14739
Author(s):  
Jixing Liu ◽  
Huifang Cheng ◽  
Huiling Zheng ◽  
Lu Zhang ◽  
Bing Liu ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Poisoning Effect ◽  
Reduction Of Nox ◽  
Insight Into

scholarly journals Byproduct Analysis of SO2 Poisoning on NH3-SCR over MnFe/TiO2 Catalysts at Medium to Low Temperatures

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 265 ◽  
Author(s):  
Tsungyu Lee ◽  
Hsunling Bai
Keyword(s):  
Reaction Temperature ◽  
Catalytic Reduction ◽  
No Oxidation ◽  
Ammonium Salts ◽  
Oxidation Reactions ◽  
No Conversion ◽  
Nh3 Scr ◽  
So2 Poisoning ◽  
No Consumption ◽  
Nh3 Oxidation

The byproducts of ammonia-selective catalytic reduction (NH3-SCR) process over MnFe/TiO2 catalysts under the conditions of both with and without SO2 poisoning were analyzed. In addition to the NH3-SCR reaction, the NH3 oxidation and the NO oxidation reactions were also evaluated at temperatures of 100–300 °C to clarify the reactions occurred during the SCR process. The results indicated that major byproducts for the NH3 oxidation and NO oxidation tests were N2O and NO2, respectively, and their concentrations increased as the reaction temperature increased. For the NH3-SCR test without the presence of SO2, it revealed that N2O was majorly from the NH3-SCR reaction instead of from NH3 oxidation reaction. The byproducts of N2O and NO2 for the NH3-SCR reaction also increased after increasing the reaction temperature, which caused the decreasing of N2-selectivity and NO consumption. For the NH3-SCR test with SO2 at 150 °C, there were two decay stages during SO2 poisoning. The first decay was due to a certain amount of NH3 preferably reacted with SO2 instead of with NO or O2. Then the catalysts were accumulated with metal sulfates and ammonium salts, which caused the second decay of NO conversion. The effluent N2O increased as poisoning time increased, which was majorly from oxidation of unreacted NH3. On the other hand, for the NH3-SCR test with SO2 at 300 °C, the NO conversion was not decreased after increasing the poisoning time, but the N2O byproduct concentration was high. However, the SO2 led to the formation of metal sulfates, which might inhibit NO oxidation reactions and cause the concentration of N2O gradually decreased as well as the N2-selectivity increased.

Mechanistic insight into the influence of O2 on N2O formation in the selective catalytic reduction of NO with NH3 over Pd/CeO2 catalyst

2021 ◽  
Author(s):  
Liping Sheng ◽  
Songda Li ◽  
Zhaoxia Ma ◽  
Fei Wang ◽  
Hu He ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
No Reduction ◽  
Catalytic Reduction ◽  
Temperature Dependent ◽  
N2o Formation ◽  
Reduction Of No ◽  
Mechanistic Insight ◽  
Insight Into

O2 greatly affected the pathway for NO reduction over the Pd/CeO2 catalyst and resulted in a temperature-dependent NH3-SCR performance and formation of N2O.

New insight into N2O formation from NH3 oxidation over MnO /TiO2 catalyst

Fuel ◽  
2019 ◽  
Vol 254 ◽  
pp. 115719 ◽  
Author(s):  
Denghui Wang ◽  
Qi Yao ◽  
Chunhui Mou ◽  
Shien Hui ◽  
Yanqing Niu
Keyword(s):  
N2o Formation ◽  
Tio2 Catalyst ◽  
Nh3 Oxidation ◽  
Insight Into

scholarly journals Effects of Ce over TiO2 supported MnOx-based Catalyst for NOx Reduction by Ammonia

2020 ◽  
Vol 185 ◽  
pp. 04026
Author(s):  
Zhi Liu ◽  
Yunqi Liu
Keyword(s):  
Catalytic Reduction ◽  
Nox Reduction ◽  
Catalyst Design ◽  
No Oxidation ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Positive Role ◽  
Fast Scr ◽  
Insight Into

Ce modified MnOx-based catalysts have attracted much attention due to its high activity for selective catalytic reduction of NOx by NH3 (NH3-SCR) at low-temperatures. However, the most important role of Ce on the NH3-SCR performance of MnOx-based catalysts has not been confirmed. Herein, the typical Ce-Mn/TiO2 catalyst was synthesized through incipient-wetness impregnation method, the positive role of Ce on Ce-Mn/TiO2 catalyst in the NH3-SCR process was revealed by combining different activity tests (including NO oxidation and NH3 oxidation) and characterizations (including XRD, XPS and He-TPDMS experiments). It was found that the introduction of Ce can promote the dispersion of MnOx on TiO2 support. Meanwhile, the doping of Ce in MnOx can also increase the content of Mn4+ species. The Mn4+ species plays a crucial role in NO oxidation reaction, which can trigger the “Fast SCR” reaction and promote the conversion of NOx. This work provides insight into the catalyst design for NH3-SCR process at low-temperature.

scholarly journals Effect of hydrothermal aging temperature on a Cu-SSZ-13/H-SAPO-34 composite for the selective catalytic reduction of NOx by NH3

RSC Advances ◽  
2021 ◽  
Vol 11 (53) ◽  
pp. 33334-33343
Author(s):  
Huawang Zhao ◽  
Mimi Lin ◽  
Yujie Wang ◽  
Jiandong Zheng
Keyword(s):  
Selective Catalytic Reduction ◽  
Aging Temperature ◽  
Catalytic Reduction ◽  
Hydrothermal Aging ◽  
Reduction Of Nox

Effect of aging temperature on SSZ-SAPO composites.

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