CHEMICAL ENGINEERING JOURNAL
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2021
·
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
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2015
·
IF 3.453
Jie Gong,Chongqing Wang,Changfeng Zeng,Lixiong Zhang
Herein we report a biosynthesis route to prepare hierarchical SAPO-34 constructed by numerous nano-sheets. Rapeseed pollen extract was used as water to prepare the synthesis solution, which underwent hydrothermal synthesis to obtain the hierarchical SAPO-34. The product is characterized by XRD , FT-IR, SEM, N 2 adsorption–desorption and TG analysis . The hierarchical SAPO-34 shows a distinctive morphology with curly nano-sheets and gaps between nano-sheets, forming a blooming flower-like structure. Its specific surface area is 683 m 2 g −1 . The effect of the content of rapeseed pollen suspension was examined. Increasing in the content leads to the formation of the hierarchical SAPO-34 constructed with curlier and much more numbers of nano-sheets. The formation process of SAPO-34 was investigated and a possible formation mechanism was proposed. Such hierarchical SAPO-34 exhibits a high CO 2 adsorption capacity of 2.77 mmol/g at 100 kPa and the CO 2 /CH 4 ideal separation factor of 8.2. It takes 6.1 min for CO 2 to reach the adsorption equilibrium, which is faster than that of conventional SAPO-34, possibly due to such nano-sheet-constructed fine structure.
研究领域:
材料科学
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环境科学
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2024
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IF 3.3
Fumei Wang,Qi Cai,Xinhua He,Boxiong Shen,Leila Negahdar,Shuo Feng,Andrew M. Beale
Cu/SAPO-34 catalysts have been widely used for the reduction of NOx from diesel exhaust by ammonia-selective catalytic reduction (SCR). Sulfur poisoning remains a challenge for Cu/SAPO-34 catalysts in NH3–SCR, restricting its application. In this study, Cu/SAPO-34 samples containing a mixture of Cu species comprising isolated Cu2+ located in the 6MR, Cu(OH)+ in 8MR, CuO clusters/nanoparticles, and Cu+ species were prepared. The Cu speciation during SO2 and hydrothermal aging of Cu/SAPO-34 SCR catalysts was subsequently studied. While hydrothermal aging had little effect on catalytic activity, the sulfur-aged sample exhibited deterioration in NH3–SCR activity over the temperature range of 100–575 °C. The breakage and collapse of the zeotype framework and chemical deactivation of the Cu/SAPO-34 catalyst after exposure to SO2 and H2O took place. A combination of X-ray photoelectron spectroscopy (XPS) and TGA-DT-DSC revealed the presence of ammonium bisulfate, copper bisulfate/sulfate, aluminum sulfate, and sulfuric acid after SO2 and H2O copoisoning under SCR conditions. Furthermore, Cu(OH)+ tended to migrate to form isolated Cu2+ and Cu+, as well as agglomerate to form CuO particles. Density functional theory (DFT) calculations revealed that SO2 and O2 could readily be absorbed by CuO particles to form stable copper bisulfate/sulfate species with the following order of preference: CuO > Cu+ > Cu2+ > Cu(OH)+. In contrast, Cu(OH)+ was less prone to be poisoned by easily releasing SO3 than other Cu species sites.
研究领域:
环境科学
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催化化学
✓ 已验证
DOI
高影响因子
CATALYSIS TODAY
·
2022
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IF 6.562
Wenwen Cong,Changyou Xu,Yahang Mu,Qiang Li,Liancheng Bing,Fang Wang,Dezhi Han,Guangjian Wang
In this work, hierarchical SAPO-34 supported PtCo bimetallic catalysts with different Pt/Co ratios were prepared by impregnation method. The obtained PtCo/SAPO-34 catalysts displayed high catalytic activities and durability for the dehydrogenation of ammonia borane (AB). Among them, Pt 1 Co 5 /SAPO-34 catalyst delivered the highest hydrogen generation activity with a turnover frequency (TOF) of 262 mol H 2 ( mol Pt ∙ min ) − 1 at 303 K as well as excellent catalytic activity in catalytic hydrogenation of 4-nitrophenol (4-NP) by coupling with hydrolytic dehydrogenation of AB, due to the electron interaction of Pt and Co in PtCo alloy and the high metal dispersion and exposure of Brønsted acidic sites on SAPO-34 support. Moreover, it is noteworthy that the prepared Pt 1 Co 5 /SAPO-34 catalyst also exhibited superior recycle stability, with 81% of the initial TOF value after five runs of hydrolysis reaction.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2021
·Vol. 11
·期 3
·314
·
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
CRYSTENGCOMM
·
2020
·Vol. 22
·期 37
·6182-6188
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IF 3.117
Xueshuai Chen,Rongli Jiang,Huilin Hou,Zihan Zhou,Xingwen Wang
ZSM-5/SAPO-34 zeolite composites were successfully synthesized by adding ZSM-5 into SAPO-34 synthetic gel under hydrothermal synthesis conditions, and SAPO-34 as a part of the composite zeolite was synthesized from LAPONITE® as the Si source. The presence of ZSM-5 in the synthetic gel affects the nucleation and crystal growth rate, and core–shell structured zeolite composites can be formed by adding an appropriate amount of ZSM-5. LAPONITE® itself contains Li and Mg atoms which were subsequently introduced into the framework of the SAPO-34 part in the composites via depolymerization–reorganization during the process of crystallization. Furthermore, the depolymerized LAPONITE® can be converted in situ into zeolitic precursors and act as crystalline seeds under hydrothermal conditions. Compared with the ZSM-5/SAPO-34 zeolite composites synthesized from tetraethylorthosilicate (TEOS) instead of LAPONITE® as the Si source, the ZSM-5/SAPO-34 composites synthesized from LAPONITE® exhibited higher selectivity to light olefins and longer lifetime in the MTO reaction. This work provides a convenient route to the synthesis of ZSM-5/SAPO-34 zeolite composites with excellent MTO performance.
研究领域:
化学工程
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材料科学
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2025
·Vol. 155
·期 5
·1-14
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IF 2.4
Yao Wenjie,Chen Lei,Wang Yinzhong,Yang Gang
The composite molecular sieve catalysts with long reaction times were successfully synthesized by introducing Cu 2+ /Mn 2+ and ZSM-5 into the initial gel. The catalysts were characterized with XRD, SEM and NH 3 -TPD, and further investigated through the methanol-to-olefin reactions. The results showed that the addition of Cu 2+ caused the crystallinity of ZSM-5/SAPO-34 (Z-S) to increase significantly, but with addition of Mn 2+ , the crystallinity gradually decreased. With the increase of the Mn 2+ /Cu 2+ ratio, the desorption summits of the weak and strong acid sites gradually increased, but the weak acid centres gradually dominated, which is herein thought helped reducing formation of the coke. The designed Cu 0.05 -Mn 0.05 /Z-S samples showed beneficial catalytic performances with a lifetime of 1500 min, a 1.5-fold increase compared with the Cu 0.05 /Z-S, while their selectivities remained exceeding 89%. Graphical
研究领域:
化学工程
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催化材料
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2023
·
IF 5.5
Jinbo Zhu,Xu Chen,Xiangge Sang,Gang Yang
SAPO-34 catalysts with high selectivity for light olefins were first synthesized via the introduction of phosphomolybdic acid (HPMo) and AlPO 4 -5 zeolite into the initial gel. The physical and chemical characteristics of the synthesized catalysts were determined by a series of techniques and the catalytic performance of the modified composite zeolites for the methanol-to-olefin (MTO) reaction was investigated. The results indicated that HPMo-modified SAPO-34 was featured with more Brønsted acid sites, more mesopores, and a smaller crystal size, thereby demonstrating superior catalytic performance. The further combination with AlPO 4 -5 (16.7 wt%) prolonged the lifetime of the HPMo-modified SAPO-34, which is thought in this paper related to its 12-ring straight channel (0.7–0.8 nm) and the absence of any Brønsted acid sites. The MTO tests showed that the light olefins selectivity for the modified composite zeolites reached 95.1 %, while the catalyst lifetime remained at 445 min
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
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
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2019
·Vol. 128
·期 2
·1029-1042
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IF 1.428
Lu Huihui,Duan Weiting,Zhao Xinhong
A cost-effective route has been developed for the synthesis of nano-sized triclinic SAPO-34 zeolite via seed-assisted grinding method using lower dosage of morpholine as the sole template. The synthesis conditions including silica source, silica concentration, crystallization temperature and time were refined to obtain SAPO-34 zeolite with high phase purity and crystallinity. Particularly, seed crystals preactivated by different methods were utilized to induce the synthesis of nano-sized SAPO-34 zeolites in the subsequent study. The resultant SAPO-34 samples were characterized by XRD, SEM, N 2 physisorption and NH 3 -TPD techniques. It was found that the introduction of seed crystals activated by mechanical milling for 20 min and chemical etching with 0.0001 M and 0.01 M H 3 PO 4 can not only effectively reduce the crystal size of SAPO-34 zeolites from 3–4 μm to 500–800 nm level, but also can modify their texture and acid properties. This nano-sized SAPO-34 catalyst exhibits a remarkably prolonged catalytic lifetime in methanol to olefins (MTO) reaction in comparison to the conventional micron-sized counterpart. Analogous to solvent-free synthesis of zeolites, this seed-assisted grinding synthesis method is simpler, more efficient than conventional hydrothermal synthesis. More importantly, this method provides a new avenue for preparing superior MTO catalyst.
研究领域:
化学工程
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催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Qibo Liu,Yi Wang,Xiaoguang Sang,Jingce Bi,Ningning Liu,Xia Zhang,Zhuopeng Wang,Yide Han
The agglomeration and leaching of metal species are critical issues for iron-based catalysts to remove tetracycline (TC) through peroxydisulfate (PDS) activation. In this work, iron-oxide species confined in cha cage of silicon aluminum phosphate zeolite (Fe-SAPO-34) was successfully synthesized by in-situ encapsulation method to address the above challenges. In Fe-SAPO-34/PDS system, approximately 92.6% TC was removed within 150 min at experimental conditions: [pH] = 3, [TC] = 20 mg/L, [Catalyst] = 0.10 g/L, [PDS] = 1 mM. Meanwhile, the biggest degradation rate constant is 0.03689 min −1 , which surpasses the counterpart systems. This result originates from the well dispersion of Fe-oxide species in Fe-SAPO-34, providing more active sites for TC degradation. As expected, the Fe-oxide species leaching concentration is ultra-low (0.018 mg/L) in Fe-SAPO-34/PDS system, which is attributed that SAPO-34 has a confinement effect of cha cage and eight-ring pore openings to limit its leaching. The radical quenching tests and electron paramagnetic resonance (EPR) technology verify singlet oxygen ( 1 O 2 ) is the primary reactive oxygen species (ROS) in Fe-SAPO-34/PDS system. Furthermore, two possible pathways for TC degradation are proposed in line with the intermediate identified by liquid chromatography-mass spectrometry (LC-MS).
研究领域:
环境科学
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2018
·Vol. 26
·期 3
·793-802
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IF 1.858
Wu Hong,Wang Xianshu,Liu Fei,Cao Jianxin
The SAPO-34/ZSM-5 composite catalyst (SZ-TS) was successfully fabricated using a two-step in situ crystallization method. X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, N 2 adsorption–desorption, and ammonia temperature-programmed desorption measurements were used to characterize the synthesized catalysts and evaluate their catalytic performances on methanol-to-olefin (MTO) reaction. The synthesis mechanism of two-step in situ crystallization was further investigated. Results showed that the SZ-TS synthesized by two-step in situ crystallization featured an intimately bonded composite structure owing to the synergistic effects of the interface. However, the physical mixture of SAPO-34 and ZSM-5 (SZ-PM) presented two discrete phase structures. By using the composite catalyst in MTO reaction, the SZ-TS exhibited the longest life of 1400 min, which was much higher than that of SZ-PM (720 min). Methanol conversion reached 97.3%, and the selectivity for light olefins totalled 93.0%. The excellent catalytic performance of SZ-TS was attributed to the hierarchical pore structure and suitably weak acid site distribution. Via pre-crystallization, alkalinity can be adjusted in the adjacent ranges of SAPO-34 and ZSM-5. By adding the pre-crystallized alkaline SAPO-34 slurry into the strong alkaline system of the parent ZSM-5 slurry, phase dissolution of SAPO-34 in the secondary crystallization solution was avoided. The external surface of SAPO-34 was etched in the alkaline environment of the secondary crystallization solution, resulting in hierarchical pore distribution, which benefited the MTO reaction. This in situ synthesis method features the advantages of simplicity, low time consumption, and low cost. Therefore, this approach possesses the potential to satisfy the demands of the MTO market.
研究领域:
化学工程
·
催化材料
✓ 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）