CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Jiahao Chen,Bin Wang,Kai Yuan,Yutang Kang,Shasha Feng,Feng Han,Hongmiao Wu,Rongfei Zhou,Zhaoxiang Zhong,Yiqun Fan,Weihong Xing
The SiC catalytic membrane combining dust removal and denitration can realize the efficacious treatment of atmospheric pollutants. Unfortunately, a large amount of SiO 2 , formed by the partial oxidation of SiC at a high temperature, results in the decreased chemical resistance of SiC catalytic membrane. In addition, the complicated preparation processes and susceptible to loss of catalytic components under harsh conditions restrict the industrial application of SiC catalytic membranes. Here, the Cu-SAPO-34(D)/SiC catalytic membranes were directly prepared via a facile one-pot hydrothermal synthesis method, which ingeniously utilized the generated SiO 2 as a Si source to participate in the growth of Cu-SAPO-34 zeolites. Excellent binding strength and chemical resistance were simultaneously realized for the SiC catalytic membranes. As a comparison, a Cu-SAPO-34(I)/SiC catalytic membrane was fabricated via the conventional two-step ion-exchange method. The 0.2 Cu-SAPO-34(D)/SiC (Cu molar ratio of 0.2) achieved the best NH 3 -SCR performance among the prepared catalytic membranes for its highly active copper and oxygen species, abundant Lewis acid sites and remarkable redox capacity. When implementing the simultaneous removal of NO and PM, the 0.2 Cu-SAPO-34(D)/SiC catalytic membrane achieved a high NO degradation performance of 98% from 200 to 280 °C, coupled with an excellent PM 0.3 (model dust with average size of 300 nm) filtration performance of 99.99%. These results were better than those of the Cu-SAPO-34(I)/SiC catalytic membrane (92% for NO degradation and 99.98% for PM 0.3 filtration). The one-pot in situ synthesis of Cu-SAPO-34(D)/SiC catalytic membrane with enhanced binding strength and chemical resistance provides a novel strategy for preparation of high-performance SiC catalytic membrane with double benefits.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Journal of Environmental Sciences
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2023
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IF 6.9
Songjin Ko,Xiaolong Tang,Fengyu Gao,Honghong Yi,Hengheng Liu,Ning Luo
In this work, the phosphomolybdate (HPMo) modification strategy was applied to improve the N 2 selectivity of MnCo-BTC@SiO 2 catalyst for the selective catalytic reduction of NO x , and further, the mechanism of HPMo modification on enhanced catalytic performance was explored. Among MnCo-BTC@SiO 2 -x catalysts with different HPMo concentrations, MnCo-BTC@SiO 2 -0.75 catalyst exhibited not only the highest NH 3 -SCR performance (∼95% at 200-300°C) but also the best N 2 selectivity (exceed 80% at 100-300°C) due to the appropriate redox capacity, greater surface acidity. X-ray photoelectron spectrometer (XPS) and temperature programmed reduction of H 2 (H 2 -TPR) results showed that the modification with HPMo reduced the oxidation-reduction performance of the catalyst due to electron transfer from Mo 5+ to Mn 4+ /Mn 3+ and prevent the excessive oxidation of ammonia adsorption species. NH 3 temperature-programmed desorption of (NH 3 -TPD) results showed that the modification with HPMo could significantly improve the surface acidity and NH 3 adsorption, which enhance the catalytic activity and N 2 selectivity. In-situ diffused reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS) revealed that modification with HPMo increased significantly the amount of adsorbed NH 3 species on the Bronsted acid site and C B / C L , it suppressed the production of N 2 O by inhibiting the production of NH species, the deep dehydrogenation of ammonia adsorption species. This study provided a simple design strategy for the catalyst to improve the low-temperature catalytic performance and N 2 selectivity.
研究领域:
催化化学
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环境科学
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DOI
PubMed
高影响因子
Catalysts
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2021
·Vol. 11
·期 3
·314
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IF 4.146
Lusha Zhou,Jinkun Guan,Chenglong Yu,Bichun Huang
The ethanol dispersion method was employed to synthesize a series of MnOx/SAPO-34 catalysts using SAPO-34 with the hierarchical pore structure as the zeolite carrier, which were prepared by facile acid treatment with citric acid. Physicochemical properties of catalysts were characterized by XRD, XPS, BET, TEM, NH3-TPD, SEM, FT-IR, Py-IR, H2-TRP and TG/DTG. NH3-SCR performances of the hierarchical MnOx/SAPO-34 catalysts were evaluated at low temperatures. Results show that citric acid etching solution at a concentration of 0.1 mol/L yielded a hierarchical MnOx/SAPO-34-0.1 catalyst withca.15 wt.% Mn loading, exhibiting optimal catalytic activity and SO2tolerance at low temperatures. Almost 100% NO conversion and over 90% N2selectivity at 120 °C under a gas hourly space velocity (GHSV) of 40,000 h−1could be obtained over this sample. Furthermore, the NO conversion was still higher than 65% when 100 ppm SO2was introduced to the reaction gas for 4 h. These could be primarily attributed to the large specific surface area, high surface acidity concentration and abundant chemisorbed oxygen species provided by the hierarchical pore structure, which could also increase the mass transfer of the reaction gas. This finding suggests that the NH3-SCR activity and SO2poisoning tolerance of hierarchical MnOx/SAPO-34 catalysts at low temperatures can be improved by controlling the morphology of the catalysts, which might supply a rational strategy for the design and synthesis of Mn-based SCR catalysts.
研究领域:
催化化学
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环境科学
✓ 已验证
DOI
高影响因子
FUEL
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2019
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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
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
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2023
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IF 2.8
Wang Yanghui,Jin Luyao,Xu Xintao,Li Jiaying,Fan Kaihao,Hu Bo,Shen Yi,Liu Xuesong
In this paper, MnO x /TiO 2 catalysts with different manganese contents were prepared by using vacuum over-impregnation method to support manganese on TiO 2 support. However, the activity temperature window was narrow and the denitrification efficiency was only 265–365 °C in the temperature zone above 80%. Therefore, doping W was used to improve the high temperature activity and broaden the activity temperature window. The experimental results show that the active temperature window of the catalyst is expanded to 260–550 °C when doping 20%WO 3 . The effects of tungsten doping on the structure and surface properties of the catalysts were investigated by XRD, TEM, Raman, XPS, H 2 -TPR and NH 3 -TPD. It is found that the increase of manganese content would increase the ratio of Mn 4+ and O α , and then improve the NH 3 -SCR activity at low temperature. Tungsten doping can provide more strong acid sites and improve the high temperature activity of the catalyst by inhibiting the oxidation of ammonia. Graphical Abstract
研究领域:
催化化学
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环境科学
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产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
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2025
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IF 6.9
Shibo Yu,Yiqing Zeng,Mengna Zhan,Shule Zhang,Zhaoxiang Zhong
The influence of phosphorus (P) on ammonia selective catalytic reduction (NH 3 -SCR) catalysts has been the subject of considerable scrutiny. Nevertheless, the precise mechanism of its influence remains a matter of contention. Furthermore, the impact of introducing P at varying stages during catalyst preparation process and its different sites within the catalyst structure on performance is frequently disregarded, significantly hindering practical guidance for designing effective modified catalysts. In this study, a series of P-modified CeO 2 /TiO 2 catalysts were synthesized by introducing P at different preparation stages, and various of characterization and comparison experiments were conducted to elucidate the effect of introducing P at different stages on NH 3 -SCR performance of NO x . Results show that introducing P before loading CeO 2 boosts catalyst activity, whereas delaying the introduction of P results in decreased activity and a progressive decline in catalyst performance as the sequence of P introduction is postponed. P introduced earlier tends to be distributed on the surface of the TiO 2 support, which contributes to the dispersion and anchoring of Ce species. In contrast, when the introduction of P was delayed, it tended to be distributed on the surface of the active species, which led to pore plugging and active sites being covered. Secondly, the variation in loading sites resulting from alterations in the stage of P introduction significantly affected on the chemical environment of Ce species, leading to notable differences in the redox capacity of the catalysts. This is the primary reason for the considerable discrepancy in the SCR performance of the catalysts. This study revealed the sensitivity of the stage of P introduction to CeO 2 /TiO 2 catalysts, providing new insights for designing modified CeO 2 /TiO 2 catalysts.
研究领域:
催化化学
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环境科学
✓ 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）