Effect of the hydrothermal aging temperature and Cu/Al ratio on the hydrothermal stability of CuSSZ-13 catalysts for NH3-SCR

2017 ◽  
Vol 7 (3) ◽  
pp. 703-717 ◽  
Author(s):  
Shuai Han ◽  
Qing Ye ◽  
Shuiyuan Cheng ◽  
Tianfang Kang ◽  
Hongxing Dai
Keyword(s):  
Aging Temperature ◽  
Catalytic Performance ◽  
Hydrothermal Stability ◽  
Hydrothermal Aging ◽  
Nh3 Scr

The effects of the hydrothermal aging temperature on the catalytic performance and stability of CuSSZ-13 catalysts with various Cu/Al ratios were studied.

scholarly journals A reconstruction strategy for the synthesis of Cu-SAPO-34 with excellent NH3-SCR catalytic performance and hydrothermal stability

2020 ◽  
Vol 41 (9) ◽  
pp. 1410-1420
Author(s):  
Lijing Sun ◽  
Miao Yang ◽  
Yi Cao ◽  
Peng Tian ◽  
Pengfei Wu ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Hydrothermal Stability ◽  
Nh3 Scr ◽  
Reconstruction Strategy

scholarly journals Effects of Lanthanide Doping on the Catalytic Activity and Hydrothermal Stability of Cu-SAPO-18 for the Catalytic Removal of NOx (NH3-SCR) from Diesel Engines

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 336
Author(s):  
Qi Gao ◽  
Shuai Han ◽  
Qing Ye ◽  
Shuiyuan Cheng ◽  
Tianfang Kang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
High Temperatures ◽  
Treatment Process ◽  
Aging Treatment ◽  
Hydrothermal Stability ◽  
Lanthanide Ions ◽  
Hydrothermal Aging ◽  
Nh3 Scr ◽  
Lanthanide Doping ◽  
Hydrolysis Of

Lanthanide (La, Ce, Nd, Gd, Tb, Ho or Lu)-doped Cu-SAPO-18 samples were prepared using the ion-exchange method. Physicochemical properties of the samples were systematically characterized by a number of analytical techniques, and the effects of lanthanide doping on catalytic activity and hydrothermal stability of the Cu-SAPO-18 catalysts for the NH3-SCR reaction were examined. It is shown that the doping of lanthanide elements could affect the interaction between the active components (copper ions) and the AEI-structured SAPO-18 support. The inclusion of some lanthanides significantly slowed down hydrolysis of the catalyst during hydrothermal aging treatment process, leading to an enhanced catalytic activity at both low and high temperatures and hydrothermal stability. In particular, Ce doping promoted the Cu2+ ions to migrate to the energetically favorable sites for enhancement in catalytic activity, whereas the other lanthanide ions exerted little or an opposite effect on the migration of Cu2+ ions. Additionally, Ce doping could improve hydrothermal stability of the Cu-SAPO-18 catalyst by weakening hydrolysis of the catalyst during the hydrothermal aging treatment process. Ce doping increased the catalytic activity of Cu-SAPO-18 at low and high temperatures, which was attributed to modifications of the redox and/or isolated Cu2+ active centers.

Enhancing catalytic performance of Cu-SSZ-13 for NH3-SCR reaction via in situ introduction of Fe3+ with diatomite

2021 ◽  
Author(s):  
Mengyang Chen ◽  
Yingzhen Wei ◽  
Jinfeng Han ◽  
Wenfu Yan ◽  
Jihong Yu
Keyword(s):  
High Temperature ◽  
Catalytic Performance ◽  
Hydrothermal Stability ◽  
Highly Efficient ◽  
Nh3 Scr ◽  
Cu Catalyst

The SSZ-13 zeolite supported Cu catalyst is highly efficient in eliminating the NOx and introduction of Fe3+ ions can significantly improve the high-temperature activity and the hydrothermal stability of Cu-SSZ-13....

scholarly journals The Hydrothermal Stability and the Properties of Non- and Strongly-Interacting Rh Species over Rh/γ, θ-Al2O3 Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 99
Author(s):  
Guanghao Cheng ◽  
Gurong Shen ◽  
Jun Wang ◽  
Yunhao Wang ◽  
Weibo Zhang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Aging Time ◽  
Reaction Path ◽  
Aging Treatment ◽  
Hydrothermal Stability ◽  
Hydrothermal Aging ◽  
Strongly Interacting

The present work reports the effects of γ-, θ-phase of alumina on the hydrothermal stability and the properties of non- and strongly-interacting Rh species of the Rh/Al2O3 catalysts. Comparing to γ-Al2O3, θ-Al2O3 can not only reduce the amount of occluded Rh but also better stabilize Rh during hydrothermal aging treatment. When the aging time was prolonged to 70 h, all the non-interacting Rh was transformed into strongly-interacting Rh and occluded Rh. The XPS results indicated that non- and strongly-interacting Rh might exist in the form of Rh/Rh3+ and Rh4+, respectively. CO-NO reaction was chosen as a probe reaction to research more information about non- and strongly-interacting Rh. The two Rh species had similar apparent activation energy (Eapp) of 170 kJ/mol, which indicated that non- and strongly-interacting Rh follow the same reaction path. The non-interacting Rh was removed from aged samples by the acid-treated method, and obtained results showed that only 2.5% and 4.0% non-interacting Rh was maintained in aged Rh/γ-Al2O3 and Rh/θ-Al2O3.

scholarly journals Novel Preparation of Cu and Fe Zirconia Supported Catalysts for Selective Catalytic Reduction of NO with NH3

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 55
Author(s):  
Katarzyna Świrk ◽  
Ye Wang ◽  
Changwei Hu ◽  
Li Li ◽  
Patrick Da Costa ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Supported Catalysts ◽  
Catalytic Performance ◽  
Experimental Conditions ◽  
One Pot ◽  
Nh3 Scr ◽  
Scr Of No ◽  
Temperature Programmed ◽  
Stationary Sources

Copper and iron promoted ZrO2 catalysts were prepared by one-pot synthesis using urea. The studied catalysts were characterized by XRD, N2 physisorption, XPS, temperature-programmed desorption of NH3 (NH3-TPD), and tested by the selective catalytic reduction by ammonia (NH3-SCR) of NO in the absence and presence of water vapor, under the experimental conditions representative of exhaust gases from stationary sources. The influence of SO2 on catalytic performance was also investigated. Among the studied catalysts, the Fe-Zr sample showed the most promising results in NH3-SCR, being active and highly selective to N2. The addition of SO2 markedly improved NO and NH3 conversions during NH3-SCR in the presence of H2O. The improvement in acidic surface properties is believed to be the cause.

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 Numerical Investigation on the Intraphase and Interphase Mass Transfer Limitations for NH3-SCR over Cu-ZSM-5

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1966
Author(s):  
Shiyong Yu ◽  
Jichao Zhang
Keyword(s):  
Pressure Drop ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Catalytic Performance ◽  
No Oxidation ◽  
Relative Pressure ◽  
Nh3 Scr ◽  
Nox Conversion ◽  
Nh3 Adsorption ◽  
Media Channels

A systematic modeling approach was scrutinized to develop a kinetic model and a novel monolith channel geometry was designed for NH3 selective catalytic reduction (NH3-SCR) over Cu-ZSM-5. The redox characteristic of Cu-based catalysts and the variations of NH3, NOx concentration, and NOx conversion along the axis in porous media channels were studied. The relative pressure drop in different channels, the variations of NH3 and NOx conversion efficiency were analyzed. The model mainly considers NH3 adsorption and desorption, NH3 oxidation, NO oxidation, and NOx reduction. The results showed that the model could accurately predict the NH3-SCR reaction. In addition, it was found that the Cu-based zeolite catalyst had poor low-temperature catalytic performance and good high-temperature activity. Moreover, the catalytic reaction of NH3-SCR was mainly concentrated in the upper part of the reactor. In addition, the hexagonal channel could effectively improve the diffusion rate of gas reactants to the catalyst wall, reduce the pressure drop and improve the catalytic conversion efficiencies of NH3 and NOx.

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