JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Kunli Song,Shuqi Zhao,Zhenguo Li,Kaixiang Li,Yurong Xu,Yijun Zhang,Yonghong Cheng,Jian-Wen Shi
SSZ-13 has been commercialized as a catalyst in diesel engines for the selectivity catalytic reduction of nitrogen oxides (NO x ) with ammonia (NH 3 -SCR), but the catalyst is facing the problem of poisoning. Herein, two well-designed catalysts, Cu-SSZ-13 and cerium (Ce) doped Cu-SSZ-13 are synthesized, and their tolerance to zinc (Zn) and phosphorus (P) poisoning alone and together are explored in detail. The research found that Zn and P poisoning alone leads to the destruction of Cu-SSZ-13 structure, resulting in the decline of denitration (de-NO x ) performance following the mechanism dominated by Eley-Rideal (E-R). Surprisingly, it is found that zinc phosphate particles are formed at inactive sites on the surface of Cu-SSZ-13 in the presence of Zn and P together, which protects the active sites, enhances the adsorption of nitric oxide. As a result, the excellent de-NO x performance of Cu-SSZ-13 is well maintained following the dual mechanism of E-R and Langmuir-Hinshelwood (L-H). In addition, the introduction of Ce stabilizes the active sites, so as to improve the de-NO x performance and the poisoning tolerance of Cu-SSZ-13. This work deeply analyzes the reasons of Zn and P poisoning and the positive effect of Ce on Cu-SSZ-13, which provides ideas for improving the poisoning tolerance of Cu-SSZ-13 and promotes the further application.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Jingang Wang,Jianbo Zhang,Cheng Xing,Taosheng Jin,Jinpeng Liu,Meiting Ju,Xuejiao Tang
Phosphorus (P) poisoning of NH 3 -SCR catalysts is inevitable in application of NO x abatement of diesel exhaust. The distinct effects on Cu-SSZ-13 of P from different precursors (H 3 PO 4 and (NH 4 ) 2 HPO 4 ) were figured out and the mechanism was further investigated. P-poisoned Cu-SSZ-13 (Si/Al = 6) catalysts were prepared and characterized using N 2 adsorption, X-ray powder diffraction (XRD), scanning electron microscope with energy-dispersive X-ray spectroscopy mapping (SEM-EDX), ammonia temperature-programmed desorption (NH 3 -TPD), X-ray photoelectron spectroscopy (XPS), hydrogen temperature programmed reduction (H 2 -TPR), electron paramagnetic resonance (EPR) and 27 Al solid-state magic angle spinning nuclear magnetic resonance spectroscopies ( 27 Al NMR). Significant enhancement of high-temperature activities (400–600 °C) were observed for the catalysts with P loading of 0.3–0.9 wt%, since the appropriate incorporation enabled to bind P atoms to CuO x in remained framework. However, the high P content of 1.5 wt% resulted in a detrimental effect on framework to induce the accumulation of Cu species. Interestingly, the dominant P from H 3 PO 4 was inclined to directly attack the framework Al leading to more severe dealumination, while the P from (NH 4 ) 2 HPO 4 interacted with Cu 2+ to form copper phosphate with more Cu 2+ migrating to the surface of the catalyst which promoted the NO x conversation at each active site resulting in the low-temperature catalytic activity unchanged. So, control of the P/Cu and form of P is capable of preventing P poisoning and unlocks the potential of Cu-SSZ-13 in exhaust treatment.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2014
·
IF 4.058
Jiancheng Wang,Zhaoliang Peng,Ying Chen,Weiren Bao,Liping Chang,Gang Feng
Cu-SSZ-13/cordierite monolithic catalyst was prepared by in situ hydrothermal synthesis method. The physicochemical properties of the as-prepared Cu-SSZ-13/cordierite were investigated by X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, N 2 -adsorption, inductively coupled plasma, X-ray photoelectron spectroscopy, and solid-state NMR techniques. The removal of nitrogen oxides (NO x ) from simulated diesel vehicle exhaust gas was performed using fixed-bed reactor. The effects of crystallization time and addition of HF during hydrothermal synthesis, reaction space velocity, and aging treatment of catalyst on the catalytic performances of NO x reduction reactions were investigated. The results indicate that the optimum crystallization time was 72 h. Highly crystalline structure of zeolite Cu-SSZ-13 was formed, in a close combination with a carrier, via one step hydrothermal process. Cu-SSZ-13/cordierite showed excellent DeNO x performance for selective catalytic reduction (SCR) and anti-aging properties in a simulated diesel exhaust gas under a high space velocity. At a high space velocity of 72,000 h −1 , the highest conversion and N 2 selectivity of 94% and 90%, respectively, were achieved. After the aging for 50 h at 720 °C, NO x reduction rate was still >80% in the temperature range of 350–550 °C. The larger height to diameter ratio of the same catalysts enhanced the NH 3 -SCR catalytic activity and broadened the active temperature window. The addition of HF increased the catalytic activity and anti-aging performance of the sample.
研究领域:
催化材料
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2021
·
IF 7.92
Yue Ma,Songqi Cheng,Xiaodong Wu,Tongxi Ma,Liping Liu,Baofang Jin,Minghan Liu,Jianbo Liu,Rui Ran,Zhichun Si,Duan Weng
To improve the hydrothermal durability of Cu-SSZ-13 selective catalytic reduction (SCR) catalyst, a thin Al 2 O 3 modification layer was coated on the external surface of Cu-SSZ-13 by a chemical liquid deposition (CLD) method. The high-temperature SCR activity of the Al-modified Cu-SSZ-13 can be maintained upon 750–800 °C hydrothermal aging, and over-oxidation of NH 3 is largely inhibited. Based on H 2 -TPR and EPR results, it is revealed that CuAl 2 O 4 -like species forms upon Al modification and converts further to CuAlO 2 -like species during aging, while the accumulation of CuO-like species is inhibited. The high affinity of Al-containing species ( i.e. , Al 2 O 3 and CuAl 2 O 4 -like species) with Cu(OH) 2 is suggested by DFT calculations, indicating that Cu(OH) 2 detached from ion-exchange sites are captured by Al to form CuAlO 2 -like species instead of CuO-like species. The passivation of detached Cu species by coated Al leads to somewhat weakened low-temperature SCR activity, but successfully preserves the high-temperature SCR performance upon aging, which can be applied to high-temperature SCR scenarios.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Han Jiang,Bin Guan,Xuesong Peng,Reggie Zhan,He Lin,Zhen Huang
This study focuses on investigating the influence of ion-exchange method (ION-F and ION-A) and one-pot method (ONE-F and ONE-A) on catalytic properties and hydrothermal stability of Cu/SSZ-13. It was found that ONE-F catalyst showed better SCR activity, especially at low temperature range below 400 °C. After hydrothermal aging, ION-A exhibited higher low temperature efficiency than ONE-A. The effect of synthesis method on the physicochemical structure, acidity intensity, and Cu species migration or transformation of the fresh and aged Cu/SSZ-13 catalysts were comprehensively characterized by NH 3 -TPO, H 2 -TPR, NH 3 -TPD, ICP, XRF, BET, XRD, SEM, and TEM. ONE-F has more isolated Cu 2+ sites, higher ratio of active sites Cu 2+ -2Z/[Cu(OH)] + -Z, more Lewis acid sites, and smaller particle size than ION-F. However, hydrothermal aging had severe effect on Cu/SSZ-13 prepared by one-pot method, leading to particle aggregation and decrease of active copper sites. According to NH 3 -SCR kinetic studies, smaller particle size and more uniformly distributed active sites over ONE-F resulted in less effect of pore diffusion limitation. Furthermore, in situ DRIFTS results indicated that more monodentate nitrates adsorbed sites and Lewis acid sites existed in ONE-F. On the other hand, monodentate nitrates were identified to be the most active nitrate species, and Lewis acid sites were ascertained to be more active than Brønsted acid sites. Therefore, ONE-F showed more excellent SCR performance than ION-F. However, hydrothermal aging resulted in loss of majority of nitrate adsorbed sites and acid sites over catalyst prepared by one-pot method, leading to lower SCR performance. In conclusion, Cu/SSZ-13 prepared by ion-exchange method has higher hydrothermal stability, however, fresh Cu/SSZ-13 prepared by one-pot method has excellent catalytic properties.
研究领域:
催化材料
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Xinyu Li,Huawang Zhao,Yating Huang,Xiaomin Wu,Zhiwei Huang,Huazhen Shen,Guohua Jing
A composite catalyst was prepared by mechanically mixing Cu-SSZ-13 and MnCeTiO x to improve selective catalytic reduction (SCR) of NO x by ammonia. The optimal mass ratio of Cu-SSZ-13 and MnCeTiO x components in the composite catalysts was 1:1, where the NO x conversion was improved by around 40% in the temperature range of 150–300 °C compared with Cu-SSZ-13 alone. MnCeTiO x presented significantly stronger ability on the activation of NO to nitrates species than Cu-SSZ-13. Infrared (IR) and density functional theory (DFT) results showed that active nitrates intermediate on MnCeTiO x might migrate to Cu-SSZ-13, which assisted the oxidation of single Cu + to Cu 2+ to complete the Cu redox cycle. This avoided the rate-determining step that formation and oxidation of Cu + dimers in low-temperature SCR over Cu-SSZ-13. The research results are beneficial to the rational design of SCR catalysts with high-performance at low temperatures.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2021
·
IF 3.171
Xin Yong,Hong Chen,Huawang Zhao,Miao Wei,Yingnan Zhao,Yongdan Li
The effects of SO 2 on an one-pot synthesized Cu-SSZ-13 catalyst for selective reduction of NO x by NH 3 were examined. The addition of SO 2 inhibited NO x conversion significantly below 300 °C, while no effect on NO x conversion was observed above 300 °C. TGA, TPD , and XPS results showed that the deactivation was caused by the formation of (NH 4 ) 2 SO 4 , SO 2 chemisorption on the isolated Cu 2+ ion sites, as well as the formation of CuSO 4 -like species. Among them, the site-blocking effect of (NH 4 ) 2 SO 4 on Cu 2+ was the primary reason for deactivation. Fortunately, 89% of deNO x activity of the poisoned catalyst was recovered after thermal treatment at 500 °C in air, where (NH 4 ) 2 SO 4 was completely decomposed. The activity was further recovered with regeneration temperature increasing to 600 °C, removing the adsorbed SO 2 on the Cu 2+ sites. The regeneration at 600 °C could not recover the activity completely, because of the high stability of CuSO 4 -like species.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2019
·
IF 12.221
Yue Ma,Songqi Cheng,Xiaodong Wu,Yunzhou Shi,Li Cao,Liping Liu,Rui Ran,Zhichun Si,Jianbo Liu,Duan Weng
Solid-state ion-exchange (SSIE) is an effictive method to prepare Cu-SSZ-13, but usually requires high temperatures or assistance of NH3 for catalyst activation. Herein, an environmentally friendly low-temperature solid-state ion-exchange (LT-SSIE) method was developed. Cu salts that can decompose at temperatures lower than 300 °C (e.g., CuAc2 and Cu(NO3)2) were chosen as Cu precursors. An impregnation method was adopted to obtain high dispersion of the precursors inside the channels of SSZ-13, as confirmed by scanning transmission electron microscopy. A calcination in air at 300 °C for 30 min was found enough for catalyst activation. In situ X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetry, ultraviolet–visible spectroscopy and H2 temperature-programmed reduction were performed to monitor the activation prcoess of CuAc2-impregnated SSZ-13. The ion-exchange sites of SSZ-13 are occupied by Cu2+ ions originating from CuAc2 at 250–300 °C, revealing the nature of the LT-SSIE process between CuAc2 and SSZ-13.
研究领域:
材料科学
·
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
AICHE JOURNAL
·
2022
·Vol. 68
·期 11
·e17834
·
IF 4.167
Wuyuan Liu,Zhaoying Wang,Ming Sun,Jiajian Gao,Lifeng Wang,Zihan Gao,Yingying Xu,Xiangyun Zhao,Cheng Zhang,Lin Yu
A series of CeO 2 modified Cu-SSZ-13 monolith catalysts were prepared by embedding CeO 2 into the washcoat of Cu-SSZ-13 monolith catalyst through solvent combustion method. These CexCu-SSZ-13 catalysts were studied in the selective catalytic reduction (SCR) of NO with NH 3 , among which the Ce2Cu-SSZ-13 catalyst exhibited the best low-temperature activity, hydrothermal stability, and sulfur resistance. The physicochemical properties of the catalysts were characterized using multiple methods. Results showed that the acidity, redox capacity, and ammonia adsorption capacity significantly enhanced after CeO 2 modification, thus leading to the high performance of Ce2Cu-SSZ-13 catalyst. Furthermore, the introduction of CeO 2 induced the fast SCR reaction by promoting the oxidation of NO to NO 2 . Analog calculation suggested that the porous structure generated via solvent combustion in the washcoat effectively increased the diffusion rate of reaction. In situ diffuse reflectance infrared Fourier transform spectroscopy ( in situ DRIFT) analysis showed that Brønsted acid sites were the main active center and the reaction followed Eley–Rideal mechanism.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED MATERIALS
·
2023
·
IF 29.4
Yingzhen Wei,Shuang Wang,Mengyang Chen,Jinfeng Han,Guoju Yang,Qifei Wang,Jiancheng Di,Hongli Li,Wenzheng Wu,Jihong Yu
Core–shell catalysts with functional shells can increase the activity and stability of the catalysts in selective catalytic reduction of NO x with ammonia x . However, the conventional approaches based on multistep fabrication for core–shell structures encounter persistent restrictions regarding strict synthesis conditions and limited design flexibility. Herein, a facile coaxial 3D printing strategy is for the first time developed to construct zeolite-based core–shell monolithic catalysts with interconnected honeycomb structures, in which the hydrophilic noncompact silica serves as shell and Cu-SSZ-13 zeolite acts as core. Compared to a Cu-SSZ-13 monolith which suffers from the interfacial diffusion, the SiO 2 shell layer can increase the accessibility of active sites over Cu-SSZ-13@SiO 2 , resulting in a 10–20% higher NO conversion at200−550 °C under 300 000 cm 3 g −1 h −1 . Meanwhile, a thicker SiO 2 shell enhances the hydrothermal stability of the aged catalyst by inhibiting the dealumination and the formation of CuO x . Other representative monolithic catalysts with different topological zeolites as shell and diverse metal oxides as the core can be also realized by this coaxial 3D printing. This strategy allows multiple porous materials to be directly integrated, which allows for flexible design and fabrication of various core–shell monolithic catalysts with customized functionalities.
研究领域:
材料科学
·
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Huawang Zhao,Yingnan Zhao,Mengke Liu,Xianghui Li,Yuhan Ma,Xin Yong,Hong Chen,Yongdan Li
Phosphorus is introduced to modify the Cu-SSZ-13 catalyst via incipient wetness impregnation, with P/Cu-SSZ-13 = 1 and 2 wt.%, and Si/Al = 4, for selective catalytic reduction of NOx with NH 3 . N 2 physisorption and XRD results show the incorporation of phosphorus as phosphate acid enhanced the hydrothermal stability of Cu-SSZ-13 significantly, during hydrothermal aging in 10 vol.% H 2 O/air at 750 °C for 16 h. NMR and Raman results suggest that phosphate ions migrate and coordinate with the framework-bonded Al species, forming a framework silicoaluminophosphate interface, thus impeding further dealumination and structure collapse. Before the hydrothermal aging, the isolated Cu 2+ ions partly interact with the phosphate ions, forming Cu-phosphate species and reducing the SCR performance. Nevertheless, the appropriate content of phosphate ions can prevent the structure collapse caused by the hydrothermal aging, remaining the isolated Cu 2+ ions as well as excellent SCR performance.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2025
·
IF 3.7
Dingding Liu,Yating Huang,Zhenguo Li,Guohua Jing,Yongdan Li,Huawang Zhao
The advancements in engine technology have led to a decrease in exhaust temperatures, hence enhancing the activity of Cu-SSZ-13 at low temperatures becomes crucial and challenging. This enhancement can be achieved using dual-phase metal oxide/Cu-SSZ-13 composite catalysts. In this work, we evaluated the comparative efficacy of Mn 3 O 4 and Mn 2 O 3 and discovered that Mn 3 O 4 exhibited a significantly superior enhancement in deNO x activity of Cu-SSZ-13 at low temperatures, achieving 95% NO x conversion at 200 °C. This is substantially higher than the conversions recorded by Mn 2 O 3 /Cu-SSZ-13 (78%) and Cu-SSZ-13 (40%). Kinetic and IR results demonstrate that Mn 3 O 4 /Cu-SSZ-13 and Mn 2 O 3 /Cu-SSZ-13 composite samples share a same low-temperature pathway, where bridged nitrates formed on the MnO x react with adsorbed on Brønsted acid sites in Cu-SSZ-13. In this reaction pathway, bridged nitrate formation is identified as the rate-determining step. The distinctive structure of Mn 3 O 4 triggers an increase in oxygen vacancies, creating a higher content of chemically adsorbed oxygen, compared to Mn 2 O 3 . Those adsorbed oxygen facilitates bridged nitrate formation. Consequently, due to the larger amount of bridged nitrate formed on Mn 3 O 4 compared to Mn 2 O 3 , the Mn 3 O 4 /Cu-SSZ-13 sample exhibits higher activity.
研究领域:
环境催化
·
材料化学
·
大气污染控制
·
化学工程
·
表面科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）