CATALYSIS TODAY
·
2019
·
IF 4.888
Yuhan Ma,Huawang Zhao,Cuijuan Zhang,Yingnan Zhao,Hong Chen,Yongdan Li
Cu-SSZ-13 is a highly active catalyst to remove NO x in the emission of diesel-powered engine. However, the enhancement of its stability in high-temperature (HT) hydrothermal conditions is a well-known challenge in application. This work presents a simple strategy to significantly improve its hydrothermal stability under HT hydrothermal condition by mechanically mixing another CHA type zeolite, Cu-SAPO-34. Both the two zeolites are synthesized via one-pot method, mixed in different ratios, and treated in 10% H 2 O/air at 750 °C for 16 h. The mixed samples are characterized before and after the hydrothermal treatment, and tested in NH 3 -SCR from 150 to 550 °C. The results show the activity of the hydrothermally treated catalysts increases with the increase of the amount of Cu-SAPO-34 up to 50 wt% in the mixed sample. The hydrothermal stability of Cu-SSZ-13 is obviously enhanced by mixing with Cu-SAPO-34. The dealumination is suppressed during the hydrothermal treatment; the framework and the isolated Cu 2+ sites are largely maintained in Cu-SSZ-13. This is attributed to the interaction between the two CHA zeolites during the hydrothermal treatment. We propose the delivery of extra-framework P species from Cu-SAPO-34 to Cu-SSZ-13 is critical to enhance the HT hydrothermal stability.
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
FUEL
·
2019
·
IF 5.128
Han Jiang,Bin Guan,He Lin,Zhen Huang
This study focuses on investigating the influence of Si/Al ratio on the performance of hydrothermally aged Cu/SSZ-13 catalysts prepared by in situ hydrothermal synthesis method. It was found that NH 3 -SCR performance and hydrothermal stability of Cu/SSZ-13 decreased with increasing Si/Al ratio. Fresh and hydrothermally aged Cu/SSZ-13 with Si/Al ratio of 6.5 showed the best SCR activity and N 2 selectivity in a broad temperature of 200–500 °C, in which more than 90% NO x was reduced with superior N 2 selectivity above 95%. The effect of Si/Al ratio on the properties of the physicochemical structure, the change of acidity intensity, and Cu species migration or transformation of the fresh and aged Cu/SSZ-13 catalysts were comprehensively characterized by NH 3 -TPO, NH 3 -TPD, H 2 -TPR, N 2 physisorption, XRD, ICP-AES, and XPS. The increase of the surface CuO species, the decrease of the amount of Cu 2+ in active sites, the chemisorption NH 3 species, the specific surface area, the total pore volume, and the increase of average pore diameter, may be the main reasons for performance deterioration over high-Si/Al-ratio catalysts after hydrothermal aging. Furthermore, in situ DRIFTS indicate that, with the increasing Si/Al ratio, the zeolitic structure was easy to collapse, and that the surface acid sites, the active copper species, as well as the adsorbed surface nitrate, decreased after hydrothermally aged. After hydrothermal aging, the amount of isolated Cu 2+ decreased, and more CuO species were aggregated, mainly coming from the conversion of the unstable isolated Cu 2+ species in D6R or CHA cages. The decrease of isolated Cu 2+ and CuO species aggregation were significant in Cu/SSZ-13 with high Si/Al ratios. The CuO leaded to the instability of the SSZ-13 skeleton structure and NH 3 oxidation promotion, resulting in catalysts deactivation.
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2025
·
IF 3.9
Jinfeng Chen,Qingze Zhang,Yuanhong Zhong,Zhaoying Wang,Yakun Guo,Ming Sun,Lin Yu
To address the limitations of molecular sieves and metal oxides in the NH3-SCR of NOx, we synthesized a novel hybrid catalyst by integrating FeNbCe metal oxides with Cu-SSZ-13. The FeNbCe comodification significantly enhanced the low-temperature performance and sulfur resistance of Cu-SSZ-13 while maintaining 100% N2 selectivity across a broad activity window. The incorporation of Fe, Nb, and Ce reduced weak-acid and Lewis-acid sites while increasing strong Brønsted-acid sites, crucial for catalytic activity. The FeNbCe/Cu-SSZ-13 catalyst exhibited an enhanced surface oxygen content and redox capacity, promoting the “fast SCR” pathway and improving N2 selectivity at low temperatures. The FeNbCe oxides synergistically reacted with SO2, protecting Cu2+ active sites from sulfur poisoning and maintaining 100% NOx conversion for 4 h after SO2 introduction, maintaining 85% within 24 h. In situ DRIFTS characterization confirmed the dominance of the Langmuir-Hinshelwood (L-H) mechanism. The FeNbCe modification represents a significant advancement in the field of NH3–SCR catalysis, offering a practical and effective solution to enhance the performance of Cu-SSZ-13 while addressing key challenges such as sulfur resistance and low-temperature activity.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2020
·
IF 3.104
Di Deng,Shujun Deng,Dandan He,Zhiheng Wang,Zhipeng Chen,Yi Ji,Guoping Yan,Guangjin Hou,Licheng Liu,Hong He
Ce- or La-doped Cu/SSZ-13 catalysts were prepared by a hydrothermal method and Cu, Ce or La ions were incorporated through stepwise ion exchange. The catalyst activity was measured for the ammonia selective catalytic reduction reaction. The structure and composition of catalyst were characterized by using X-ray diffraction, scanning electron microscopy, inductively coupled plasma mass spectrometry solid-state NMR, NH 3 -TPD techniques, and the active components were examined by XPS and XANES . The results indicate that the Ce and La doping can both completely preserve the SCR activity of Cu/SSZ-13 above 300 °C, but there is also a decrease of activity below 200 °C. On the other hand, Ce doping is beneficial to the formation of framework aluminum , stabilizes molecular sieve framework and Cu active sites of Cu/SSZ-13, thereby improves the catalyst hydrothermal stability. But La doping will decrease the amount of framework aluminum and Cu active sites of Cu/SSZ-13 after hydrothermally aging, even destroy zeolite CHA structure. This is quite harmful to the catalyst hydrothermal stability.
研究领域:
催化
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环境化学
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材料科学
✓ 已验证
DOI
高影响因子
Reaction Chemistry & Engineering
·
2022
·Vol. 7
·期 10
·2121-2131
·
IF 5.2
Yue Ma,Zhimin Shao,Xiaodong Wu,Yang Gao,Baofang Jin,Rui Ran,Zhichun Si,Zhenguo Li,Duan Weng
Urea is applied as an ammonia source for SCR in diesel vehicles, but incomplete urea decomposition may lead to insufficiency of NH3 and deposition of solid by-products. To improve the urea decomposition activity of Cu-SSZ-13 SCR catalysts, Cu-SSZ-13 was combined with TiO2 nanoparticles by a simple impregnation method. TiO2/Cu-SSZ-13 composites exhibited lowered decomposition temperatures of urea and related solid by-products. Thus, the composited catalysts showed higher NOx conversion and a lower amount of urea-related deposits than unmodified Cu-SSZ-13 in a simulated urea deposition scenario. The superiority of the urea decomposition activity of the composited catalysts was maintained upon 800 °C hydrothermal aging due to stabilized anatase over the catalysts according to XRD and Raman spectroscopy. H2-TPR, UV-vis, and STEM revealed the formation of Cu–Ti–O species due to Cu–Ti interactions, which was adverse to SCR activity, but no extra hydrothermal aging effect was observed on the composited catalysts compared with unmodified Cu-SSZ-13. This work showed the potential to improve the low-temperature urea-SCR performance of Cu-SSZ-13 via TiO2 modification.
研究领域:
催化
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环境科学
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材料科学
✓ 已验证
DOI
高影响因子
ACS Catalysis
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2025
·
IF 13.1
Zhiying Liu,Meiqing Shen,Shuhuan Wang,Chunjuan Zhang,Jun Wang,Wei Li,Feng Gao
To elucidate how CeO2 additives enhance the activity and stability of Cu-SSZ-13 SCR catalysts, we investigated two CeO2/Cu-SSZ-13 composite catalysts with Cu loadings of 1.0 and 2.5 wt %. These catalysts were characterized using an array of techniques, including XRD, SEM, TEM, NMR, H2-TPR, NH3-TPD, DRIFTS, DFT and SCR reactions under both steady-state and transient kinetic analysis conditions. Our findings demonstrate that CeO2 promotes low-temperature SCR by forming exchanged, isolated Ce-ions, which enhance Cu-ion coupling efficiency. External surface CeO2 particles can convert NO + O2 to surface nitrates, but these species primarily act as spectators below ∼250 °C, and do not contribute to the enhancement of low-temperature SCR activity. In contrast, these surface CeO2 particles can synergizes with Brønsted acid sites (BAS) to elevate high-temperature SCR activity. Furthermore, hydrothermal stability and sulfur resistance are improved by the presence of external surface CeO2 particles, a benefit that applies irrespective of Cu loading.
研究领域:
催化
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环境化学
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材料科学
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物理化学
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表面科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2025
·
IF 13.2
Zhikang Xu,Mingbin Gao,Xing Wu,Haibo Zhu
Pt-Cu bimetallic particles have been regarded as promising catalysts for propane dehydrogenation. The dispersion of Pt and Cu species on conventional supports always results in the formation of large Pt-Cu particles, and it is highly desirable to fabricate ultra-small Pt-Cu cluster catalysts for propane dehydrogenation. Herein, we used the isolated Cu species in the Cu-SSZ-13 to localize the Pt species and the alloying of Pt with Cu leads to a formation of ultra-small (<1 nm) Pt-Cu bimetallic clusters in the structure of SSZ-13. The structure of synthesized PtCu-SSZ-13 catalysts was studied by XRD, SEM, STEM, XPS, CO-FTIR, H 2 -TPR and EXAFS techniques, which demonstrates that Pt-Cu clusters are entrapped in the micropore of SSZ-13 and their migration can be greatly inhibited. The synthesized PtCu-SSZ-13 catalyst shows high activity and good regeneration in propane dehydrogenation. The optimized catalyst 0.3 %PtCu-SSZ-13 delivers propane conversion of 28.5 % (close to equilibrium conversion) with 100 % propane as feed under WHSV of 7.1 h −1 at 520°C, and its catalytic performance can be completely regenerated via calcination in air. Density functional theory (DFT) calculations indicate that the unique Pt-Cu bimetallic nanocluster structure reduces the energy potential for propane dehydrogenation as well as promotes the adsorption of C 3 H 8 and desorption of C 3 H 6 thus enhancing the activity of the PtCu-SSZ-13 catalyst.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2020
·
IF 5.825
Ye Ma,Shichao Han,Qinming Wu,Longfeng Zhu,Huimin Luan,Xiangju Meng,Feng-Shou Xiao
The metal-exchanged zeolites as catalysts have been widely applied in many catalytic reactions , but their syntheses are environmentally unfriendly due to the multiple steps such as ion-exchange for the formation of a large amount of wastes. Herein, we for the first time report a method for one-pot fabrication of metal-zeolite catalysts (M-SSZ-13, M-Beta, M-ZSM-5, and M-EU-1; M = Cu, Co, Ni) from a combination of solvent-free and sodium-free routes by mixing, grinding, and heating the raw materials of aluminosilicate gel, organic templates, and metal-amine complexes. As a typical example, Cu-SSZ-13 zeolite is successfully synthesized from heating the mixture of aluminosilicate gel, organic template, and Cu-amine complex. Catalytic tests in selective catalytic reduction of NO x with NH 3 (NH 3 -SCR) show that the synthesized Cu-SSZ-13 zeolite before and after hydrothermal aging at 750 °C for 16 h are completely comparable with the commercial Cu-SSZ-13 zeolite from the conventional hydrothermal synthesis. Very interestingly, the method in this work has obvious advantages such as high yield, reduced pollutants, and simple process, which should be potentially important for practical applications of the metal-zeolites in the future.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2026
·
IF 7.5
Yang Gao,Yue Ma,Letong Yang,Xiaodong Wu,Rui Ran,Yanyang Yu,Duan Weng
Cu-SSZ-13, a Cu-exchanged zeolite, has been applied as a NO x selective catalytic reduction (SCR) catalyst for diesel aftertreatment, but improving its durability remains a challenge. To address this issue, a core–shell Cu-SSZ-13@SAPO-34 catalyst was prepared by a microwave-assisted hydrothermal method. The evolution of copper species and zeolite framework during high-temperature hydrothermal aging, potassium poisoning and sulfur poisoning, as well as the impacts on SCR performance, was explored. Cu 2+ ions detached by hydrothermal aging could migrate from the Cu-SSZ-13 core to the SAPO-34 shell and be reactivated, owing to the close interface contact between the zeolites. When exposed to chemical poisoning by K + and SO 2 , the SAPO-34 shell effectively shielded the Cu-SSZ-13 core. Thus, more active Cu 2+ ions could be preserved to maintain the SCR performance of the catalyst.
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Xueqin Wang,Tiesen Li,Chan Wang,Qingyan Cui,Tinghai Wang,Xiaojun Bao,Yuanyuan Yue
Designing a cost-effective and fast fabrication Cu-SSZ-13 with improved selective catalytic reduction of NO by ammonia (NH 3 -SCR) performance remains an open question. Here we report that LaCe-SSZ-13 zeolites were synthesized from spent fluid catalytic cracking catalyst within 12 h. After ion-exchanging with CuSO 4 solution, the obtained LaCeCu-SSZ-13 catalysts exhibit significantly higher catalytic activity and hydrothermal stability than conventional Cu-SSZ-13. Various characterizations reveal that La and Ce modification not only facilitates the disperse of isolated Cu 2+ species, but also effectively mitigates dealumination and inhibits copper species aggregation after hydrothermal aging. In-situ diffuse reflection infrared Fourier transform spectrum analyses demonstrate that La and Ce modification can accelerate the adsorption capacity for NH 3 and NO x and promote the decomposition of NH 4 NO 3 intermediate species on the catalyst, benefiting the improvement of low-temperature activity. The combination of experiments and theoretical calculations further demonstrate that the most stable positions of La and Ce are on different eight-membered rings in SSZ-13, and then Cu 2+ ions tend to enter eight-membered rings to enhance the NH 3 adsorption capacity and decrease the H 2 O adsorption capacity, which results in higher low-temperature activity and hydrothermal stability than Cu-SSZ-13. Our work provides a feasible strategy for preparing the efficient rare-earth-modified Cu-zeolite based NH 3 -SCR catalyst for nitrogen oxide abatement.
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）