Inorganic Chemistry Frontiers
·
2019
·Vol. 6
·期 11
·3097-3103
·
IF 5.934
Lingxue Tang,Kok-Giap Haw,Ping He,Qianrong Fang,Shilun Qiu,Valentin Valtchev
SSZ-24, an AFI-type aluminosilicate, proved to be a zeolite with poor synthesis reproducibility and a slow crystallization rate. The present study deals with the preparation of SSZ-24 by a seed-assisted approach. SSZ-13 and SSZ-24 zeolites are employed as seeds and the impact of the seed content on the formation of SSZ-24 is studied. Both types of zeolites accelerate the zeolite nucleation, shorten the crystallization time, and lead to the formation of pure and highly crystalline SSZ-24. In addition, SSZ-13 seeds are more efficient in terms of rapid crystallization and crystallinity level. Pure and highly crystalline SSZ-24 is readily obtained even though the amount of SSZ-13 seeds was decreased to a “catalytic level”, i.e. 0.3 wt%. The higher seeding power of SSZ-13 seeds is attributed to the presence of framework Al, which stabilizes structural elements that promote the SSZ-24 nucleation.
研究领域:
材料科学
·
无机化学
·
催化
✓ 已验证
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2019
·
IF 4.182
Bei Liu,Xiaohui Zhao,Wenting Mao,Haijun Chen,Lu Han,Kake Zhu,Xinggui Zhou
Generation of hierarchical zeolites is an effective way to enhance their diffusion-dependent catalytic properties. The fabrication of hierarchical zeolites with enhanced diffusion property, high hydrothermal stability, strong acidity in an inexpensive, facile and efficient way is particularly daunting. Here, a simple synthesis of hierarchical SSZ-13 zeolite in a biphasic water/toluene media under tumbling assisted by organosilane, i.e., trimethoxy[3-(phenylamino)propyl]silane, is proposed. The obtained material with tunable Si/Al from 10 to 30 consists of assembled crystallites of 20–30 nm that construct a hierarchical architecture with mesopores of ca . 7 nm opening to the external facets, and has low defect concentration and preserved strong acidity. Crystallization mechanism is disclosed to obey a non-classic attachment growth of nano building blocks mediated by Pickering emulsion , as organosilane modification changes their surface to be hydrophobic. Such a crystallization pathway has accelerated nucleation process and suppressed the growth of SSZ-13 crystals to micron size. Cu exchanged hierarchical SSZ-13 outperforms the standard sample in typical NH 3 -SCR process in both low and high temperature regimes as a result of enhanced diffusion property, as well as low defect concentrations. The synthesis is a cost-effective method for the generation of hierarchical zeolites mediated by the presence of a liquid/liquid interface, and could inspire more such explorations.
研究领域:
材料科学
·
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
JOURNAL OF MATERIALS SCIENCE
·
2017
·Vol. 52
·期 17
·10156-10162
·
IF 2.599
Cui Yucun,Tong Xueting,Li Ying,Chen Mingjiong,Zhou Wenyong,Ren Silin,Li Lei,Yan Zheng,Zhu Longfeng
We show that a nickel-amine complex (nickel-diethylenetriamine, Ni-DETA) is an efficient organic template for the one-pot synthesis of Ni-SSZ-13 zeolite. The effects of the reaction compositions, including the molar ratios of SiO 2 /Al 2 O 3 , H 2 O/Al 2 O 3 , Ni-DETA/Al 2 O 3 , and Na 2 O/Al 2 O 3 , on the synthesis of the pure product were investigated using different temperatures and synthesis times. Physicochemical characterizations, including XRD, SEM, and 27 Al NMR, show that the zeolitic product has good crystallinity, uniform crystals, and contains a tetrahedral Al 3+ species. The N 2 sorption isotherms, TG–DTA curves, IR spectra, and UV–Vis spectra show that Ni-DETA acts as a template in the product obtained. Interestingly, Ni-SSZ-13 zeolite is obtained by the conversion of Ni-Y zeolite produced in the crystallization process.
研究领域:
材料科学
·
化学工程
✓ 已验证
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
FUEL
·
2024
·
IF 6.7
Zongyang Zhang,Yuping Li,Ze Chen,Fuchao Ji,Xiaohong Liang,Haicheng Xuan,Lina Han,Peide Han
Developing an economical and high-efficiency synthesis pathway of SSZ-13 zeolite is of great significance for the ammonia selective catalytic reduction of nitrogen oxides (NH 3 -SCR of NO x ) reactions. Herein, SSZ-13 zeolite were synthesized using L zeolite as the aluminum source in the presence of a mixed structure directing agent (SDA) composed of N,N,N, trimethtyl-1-adamantammonium hydroxide (TMAdaOH) and tetraethylammonium hydroxide (TEAOH). This synthesis strategy aims to accelerate the crystallization rate through interzeolite transformation, while less expensive TEAOH can play a cooperative structure-directing role, thus reducing the consumption of expensive TMAdaOH template. The results showed that pure SSZ-13 zeolites with high crystallinity can be obtained from L zeolite within 12 h at 160 ℃ under low TMAdaOH/SiO 2 ratio of 0.05 (too low to carry out the synthesis on its own in the current synthesis system) in the presence of TEAOH. Moreover, the crystallization mechanism was also investigated by XRD, FT-IR, SEM and TG-DTG techniques. It was proposed that the crystallization of SSZ-13 occurs through the formation of SSZ-13 nuclei under the direction of TMAdaOH and promotion of TEAOH, subsequently TMAdaOH was incorporated in the framework to further induce the crystal growth of SSZ-13. Especially, the zeolite crystal size can be modulated by the amount of TEAOH added. In addition, After Cu 2+ exchange, the obtained Cu-SSZ-13 sample exhibits superior catalysis performance in the NH 3 -SCR of NO x reaction, and the NO x conversion rate remained over 90 % across a broad range from 200 to 600 °C, demonstrating its significant application potentials in NO x removal from diesel vehicle exhausts.
研究领域:
材料科学
·
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Liancheng Bing,Zan Sun,Shuaiguo Zhang,Baoyu Chen,Hongxia Zhang,Min Wang,Changqing Chu,Dezhi Han,Jiankang Zhang,Fang Wang,Guangjian Wang
Direct dehydrogenation of propane to propylene (PDH) is a promising route to meet the ever-growing global propylene demand, but the industrial Pt-based catalysts usually suffer from serious deactivation derived from coke deposition and sintering under harsh reaction conditions. In this work, PtZn bimetallic nanoparticles encapsulated into high-silica SSZ-13 zeolites (PtZn@SSZ-13) were synthesized via a facile ligand-protected interzeolite transformation strategy. In a PDH reaction, the synthesized 0.5Pt3Zn@SSZ-13 catalyst exhibits superior catalytic performance with a propane conversion of 23.7% and a propylene selectivity of 96.8%, which is significantly better than that of PtZn supported on high-silica SSZ-13 (0.5Pt3Zn/SSZ-13). Particularly, the high catalytic activity of this catalyst can be kept during three successive oxidation–reduction cycles. Detailed characterizations including HAADF-STEM, XPS, UV–Vis, H 2 -TPR reveal that the remarkable improvement of PDH performance is attributed to the PtZn synergistic effect as well as the confinement of SSZ-13 zeolites. The DFT calculations and microkinetic simulations also evidenced that the Pt particles anchored on the Zn-doped SSZ-13 zeolite pore framework possessed obviously higher propane dehydrogenation activity, whereas the anti-coking ability of 0.5Pt3Zn@SSZ-13 was also stronger than Pt (1 1 1) surface, demonstrating the superior performance of 0.5Pt3Zn@SSZ-13.
研究领域:
化学工程
·
材料科学
·
催化反应
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2023
·
IF 3.8
Yahang Mou,Changyou Xu,Zan Sun,Shuhua Liu,Fang Wang,Dezhi Han,Guangjian Wang,Liancheng Bing
Nano-sized SSZ-13 with hierarchical structure were fast synthesized by combining ultrasonic pretreatment and seed induced crystallization. The physicochemical properties of the synthesized catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), N 2 adsorption–desorption, X-ray fluorescence (XRF), Transmission electron microscopy (TEM), and temperature programmed desorption of ammonia (NH 3 -TPD) analysis. As verified by XRD and SEM, ultrasonic pretreatment not only remarkably reduced the crystallization time to 7 h but also evidently decreased the zeolite crystals to nano size (ca. 650 nm). The N 2 adsorption–desorption and TEM resulted revealed that ultrasonic pretreatment created abundant intracrystalline mesopores in the zeolite structures. In comparison to the conventional SM-24 catalyst, both improved catalytic lifetime and selectivity of ethylene and propylene were obtained over the hierarchical nano-sized SN-17 catalyst due to the greatly enhanced mass transport efficiency and decreased coking rate.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2021
·
IF 5.455
Huifang Zhang,Qi Dong,Peng Shan,Dahai Pan,Binbin Fan,Ruifeng Li
In this work, a highly crystallized SSZ-13 (STM-24) was successfully synthesized with sodium silicate as silica source in the co-existence of seeds and a small amount of N,N,N- trimethyl-1-adamantanamine hydroxide (TMAdaOH, TMAdaOH/SiO 2 = 0.02). The TMAdaOH amount is about one-seventh of that used in the conventional synthesis method. The SSZ-13 samples synthesized by this method were characterized by XRD , SEM, N 2 adsorption/desorption, ICP , FT-IR, UV-Raman, NH 3 -TPD, 27 Al and 29 Si NMR, and compared with SSZ-13 synthesized by conventional method at TMAdaOH/SiO 2 = 0.14 (TMA-0.14-48). The results show that STM-24 and TMA-0.14-48 have comparable textural properties and acidity, except STM-24 shows a smaller particle size than TMA-0.14-48. Moreover, the SiO 2 /Al 2 O 3 ratios of SSZ-13 synthesized by this method are controllable in a wide range of 7.3–21.5. The synergistic effect between seeds and a small amount TMAdaOH is the key to successful synthesis of SSZ-13. Additionally, Cu-STM-24 and Cu-TMA-0.14-48 catalysts show similar catalytic performances in SCR reaction. The synthesis method reported in this work provides a new and alternative way for a low-cost and efficient synthesis of SSZ-13.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
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
Molecular Catalysis
·
2023
·
IF 4.6
Jing Li,Suxia Ma,Ke Ren,Nuo Xu
SSZ-13 zeolite was synthesized from fly ash using a combined alkali fusion hydrothermal method. The optimal synthesis parameters are as follows: NaOH/FA=1.4, SiO 2 /Al 2 O 3 =50, H 2 O/SiO 2 =1800, TMAda-OH/Al 2 O 3 =7, the amount of SSZ-13-seed=10%, and crystallization time and temperature were 160 °C and 40 h. Based on this, a series of fly ash-based Fe-SSZ-13 catalysts were prepared using three different methods and tested in catalytic oxidation with H 2 O 2 for NO removal. The experiment results showed that the NO removal efficiency catalyzed by Fe-SSZ-13-SSIE, Fe-SSZ-13-LIE and Fe-SSZ-13-IM were 78%, 87% and 84%, respectively. ESR was used to detect hydroxyl radicals, UV-vis, XPS and H 2 -TPR were applied to test the composition, state and distribution of iron species, while NH 3 -TPD and Py-FTIR were performed to analyze the intensity and type of acidic sites, and finally to determine the relationship between catalyst structure, active species and catalytic performance in combination with NO removal experiments. The catalytic oxidation mechanism analysis revealed that the excellent catalytic performance can be attributed to the dual function of strong Brønsted acidity on the surface and isolated Fe 3+ with high dispersion, which can rapidly decompose H 2 O 2 into ·OH and efficiently achieve NO oxidation. In conclusion, the preparation of fly ash catalysts has great potential for achieving the dual function of waste utilization and pollutant removal.
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
危险品化学品经营许可证（带存储）