Catalysts
·
2021
·Vol. 11
·期 5
·616
·
IF 4.146
Li Han,Xinxin Yan,Lulu Guo,Yanan Duan,Zheng Wang,Tianliang Lu,Jun Xu,Yuzhong Zhan,Jianfeng Wang
A triclinic SAPO-34 molecular sieve was synthesized ionothermally. The as-synthesized products were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), nuclear magnetic resonance (NMR), fourier infrared spectrometer (FT-IR) and thermogravimetric (TG) analyses. The formation mechanism of the hierarchical porous triclinic SAPO-34 zeolites and the factors affecting the morphology of the SAPO-34 molecular sieve were investigated. The results show that the formation mechanism of the hierarchical pores is in accordance with Ostwald ripening theory, and the accumulation of grains constitutes the existence of mesopores and macropores. The crystallization temperature, ionic liquid type, and organic amines can effectively change the morphology and crystallinity of the SAPO-34 molecular sieve. The crystallization temperature, ionic liquid and template have great influence on the (111) crystal plane, thus affecting the morphology of the molecular sieve. Moreover, it can be proven through NMR and TG analyses that ionic liquids and organic amines can be used as structure directing agents together.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Jun Mou,Xingqi Fan,Fei Liu,Xiaodan Wang,Tianxiang Zhao,Peng Chen,Ziwei Li,Chunliang Yang,Jianxin Cao
The direct conversion of CO 2 hydrogenation to lower olefins via methanol as an intermediate is of great significance, but challenges still remain. Herein, we present a binary Mn 2 O 3 -ZnO oxide, which is responsible for catalytic hydrogenation of CO 2 to methanol. After combination of Mn 2 O 3 -ZnO and SAPO-34 molecular sieve, the catalytic reaction displays a markable increase. CO 2 adsorption by alkaline nature, followed by oxygen vacancy activation and synergistic hydrogenation over the binary Mn 2 O 3 -ZnO oxide are the prerequisites for the tandem reaction. However, the tandem spacing between oxide and molecular sieve plays a crucial role, because the suitable intimacy can induce enhanced methanol formation as intermediate via tandem dynamics effect, causing an apparent limitation for reverse water gas shift reaction at high temperature. The optimum mass ratio of 3:1 for two phases demonstrates that more components of binary oxide are needed to improve the rate of CO 2 hydrogenation to methanol, aiming to balance the two-step tandem reaction. Finally, under conditions of 380 ℃, 3 MPa and 3600 mL/g cat /h, 20%Mn 2 O 3 -ZnO/SAPO-34 tandem catalyst is obtained by physical ball milling after 15 min, with excellent stability, sulfur tolerance and catalytic performance with CO 2 conversion at almost 30%, lower olefins selectivity of 80.2% (propylene/ethylene = 5.6:1), and single-pass yield of 10.7%.
研究领域:
催化化学
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能源化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2020
·
IF 3.421
Chenglong Wen,Jundong Xu,Xueman Wang,Yu Fan
A novel SO42–/ZrO2@SAPO-11 (SZ@SA-11) composite was synthesized via a two-step method, and the corresponding SZ@SA-11 supported Pt catalyst was applied to catalyze n-heptane hydroisomerization. First, UiO-66@SAPO-11 is produced by the growth of UiO-66 on SAPO-11 due to the covalent bonds between Zr and the oxygen in the hydroxyl groups of SAPO-11. Then, UiO-66@SAPO-11 is decomposed to form ZrO2@SAPO-11 via calcination in air, and the SZ@SA-11 composite is obtained by the impregnation of ZrO2@SAPO-11 with (NH4)2SO4 and subsequent calcination. Compared with the physical mixture of SO42–/ZrO2 and conventional SAPO-11 (SZ+SA-11), SZ@SA-11 possesses smaller ZrO2 particles and more tetragonal ZrO2. Moderate and strong Brønsted acid sites (MSBAS) are produced only via interactions between tetragonal ZrO2 and sulfate, so SZ@SA-11 with more tetragonal ZrO2 has a greater amount of MSBAS than SZ+SA-11. These advantages of SZ@SA-11 endow the corresponding Pt/SZ@SA-11 catalyst with a better performance for n-heptane hydroisomerization compared to Pt/(SZ+SA-11). In addition, compared with the other counterparts such as Pt/SZ and Pt/SA-11, Pt/SZ@SA-11 presents higher selectivity for total isomers (91.5%), higher selectivity for multibranched isomers (22.6%), and a lower cracking selectivity (8.1%) in n-heptane hydroisomerization. The strategy proposed herein provides a new insight into the acidity adjustment of the molecular-sieve-based catalysts for hydrocarbon hydroisomerization.
研究领域:
催化化学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
Reaction Chemistry & Engineering
·
2024
·
IF 3.4
Haobin Hu,Ke Ma,Zhenyu Cheng,Xinyu Qi,Haiyan Song,Zhijun Li,Yufeng Wang,Penghui Zhang,Chengyi Dai,Xiaoxun Ma
The methanol-to-olefins reaction is a viable and promising technological route to replace increasingly scarce petroleum resources. SAPO-34 zeolite is an ideal catalyst for the methanol-to-olefins reaction due to its suitable acidity and pore structure. However, a single zeolite catalyst has limited performance, and in this work, metal species were introduced on SAPO-34 molecular sieves to achieve higher low-carbon olefin selectivity through the modulation of acidity. However, since the introduction of metals promotes aromatic cycling, it allows the creation of carbonaceous precursors and reduces the catalyst lifetime. Therefore, the introduction of CO2 into the carrier gas inhibited the generation of carbonaceous precursors and thus prolonged the catalyst life. The presence of the metal species and their effects on SAPO-34's pores and structure were characterized by XPS, the change in acid amount was determined by NH3-TPD, and the adsorption strength of the catalyst for CO2 was determined by CO2-TPD, revealing the active sites of the catalyst. High low-carbon olefin selectivity and long catalyst life were also achieved, with low-carbon olefin selectivity of 88.0%.
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
Separations
·
2022
·Vol. 9
·期 3
·64
·
IF 3.344
Weibin Cai,Jiangyu Xie,Jingyu Luo,Xiaohan Chen,Mingqian Wang,Yujun Wang,Jiding Li
In this study, zeolite molecular sieve SAPO-34/polydimethylsiloxane (PDMS) mixed matrix membranes (MMMs) were prepared to recover propane. n-Octyltrichlorosilane (OTCS) was introduced to improve compatibility between SAPO-34 and PDMS, and enhance the separation performance of the MMMs. Physicochemical properties of the MMMs were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and water contact angle (WCA). Results showed that, after modification, alkyl chains were successfully grafted onto SAPO-34 without changing its crystal structure, particles in the MMMs were evenly distributed in the base film, and the hydrophobicity of the MMMs was enhanced. Moreover, the effects of SAPO-34 filling content, operating pressure, and feed gas concentration on the separation performance was explored. This indicated that the modification with OTCS effectively enhanced the separation performance of SAPO-34/PDMS MMMs. When the filling content of modified SAPO-34 was 15%, the maximal separation factor of 22.1 was achieved, and the corresponding propane permeation rate was 101 GPU.Keywords:MMMs;SAPO-34;PDMS;OTCS;propane recovery
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
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2023
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IF 5.7
Saisai Liu,Jing Liu,Guanyi Chen,Jingang Yao,Beibei Yan,Weiming Yi,Chunyan Tian,Huijie Zao
Herein, spherical and nanosheet-like SAPO-11s were successfully synthesized hydrothermally and utilized to catalyze the methanol-to-gasoline (MTG) process. The nanosheet-like SAPO-11 (SAPO-11-A) had a thickness of about 10 nm, while the spherical SAPO-11 (SAPO-11-B) had a particle size of around 11 μm. Compared to SAPO-11-B, the property of SAPO-11-A was enhanced by 42.9% in specific surface area (SSA), 38.1% in mesopore volume (V me ) and 20.2% in acid amounts, respectively. In terms of catalytic performance during the MTG reaction, SAPO-11-A demonstrated superior results not only in the methanol conversion (95.82%), gasoline-range hydrocarbons selectivity (58.76%) and iso/nparaffin ratio (8.17) but also in suppressed coke deposition (2.56%) compared with those (90.63%, 50.95%, 4.75 and 5.73%, respectively) of SAPO-11-B. Additionally, the optimal MTG process conditions were identified utilizing SAPO-11-A, demonstrating a methanol conversion rate of 98.34%, a gasoline hydrocarbon selectivity of 67.61%, an isoparaffin selectivity of 36.01% and an iso/nparaffin ratio of 10.94 at 380 °C, weight hourly space velocity (WHSV) of 2 h −1 and 1 MPa. These results highlight the potential of nanosheet SAPO-11 to produce gasoline-range hydrocarbons rich in isoparaffins.
研究领域:
催化化学
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能源材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 11
·6110-6119
·
IF 2.936
Chengkai Pang,Yuqun Zhuo,Qiyu Weng,Zhenwu Zhu
The activity and hydrothermal stability of Cu/SAPO and xMn–2Cu/SAPO for low-temperature selective catalytic reduction of NOx with ammonia were investigated. An ion-exchanged method was employed to synthesize xMn–2Cu/SAPO, which was characterized by N2 adsorption, ICP-AES, X-ray diffraction (XRD), NH3-temperature programmed desorption (NH3-TPD), NO oxidation, X-ray photoelectron spectrum (XPS), UV-vis, H2-temperature programmed reduction (H2-TPR) and diffuse reflectance infrared Fourier transform spectra (DRIFTS). 2Mn–2Cu/SAPO and 4Mn–2Cu/SAPO showed the best SCR activity, in that at 150 °C NO conversion reached 76% and N2 selectivity was above 95% for the samples. NO oxidation results showed that the 2Mn–2Cu/SAPO had the best NO oxidation activity and the BET surface area decreased as manganese loading increased. XRD results showed that the metal species was well dispersed. NH3-TPD showed that the acid sites have no significant influence on the SCR activity of xMn–2Cu/SAPO. H2-TPR patterns showed good redox capacity for xMn–2Cu/SAPO. UV-vis and H2-TPR showed that the ratio of Mn4+ to Mn3+ increased as manganese loading increased. XPS spectra showed a significant amount of Mn3+ and Mn4+ species on the surface and addition of manganese increased the ratio of Cu2+. The promotion effect of manganese to 2Cu/SAPO comes from the generation of Mn3+ and Mn4+ species. Deduced from the DRIFTS spectra, the Elay–Rideal mechanism was effective on 4Mn–2Cu/SAPO.
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
CRYSTAL GROWTH & DESIGN
·
2014
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IF 4.558
Jie Gong,Fei Tong,Xiaobo Ji,Changfeng Zeng,Chongqing Wang,Yinong Lv,Lixiong Zhang
We herein report novel hollow SAPO-34 cubes with a hierarchical internal structure. They are prepared from dry gels containing gelatin by a vapor-phase transport method. Microscopic characterization reveals that the cubes are constructed by symmetrically packed four two-top-point truncated octahedrons encapsulated by dense crystalline shells, exhibiting a structure-in-structure formation. The cubes show either +-shaped or the butterfly like X-shaped black spots on their faces under light. Investigation of the formation process of the hollow SAPO-34 cubes demonstrates a surface to core crystal growth route, which has not been found in vapor-phase transport synthesis of zeolites. A possible formation mechanism is proposed.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2022
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IF 5.477
Tao Zheng,Peng He,Rui Zhang,Xianghai Meng,Yuanyuan Yue,Hongtao Liu,Zhichang Liu,Chunming Xu,Haiyan Liu
Background In the past decades, seed-assisted synthesis of zeolites has become one of the research focuses. Understanding the effect of the seeds on their derived products, and thus tuning the physicochemical properties of those products by selecting suitable seeds is pivotal for synthesizing zeolites via seed-assisted method. Methods In this work, four kinds of SAPO-34 with different physicochemical properties were synthesized and used as seeds to prepare their corresponding products via the seed-assisted method. The physicochemical properties of the seeds and the corresponding products were characterized by XRD, SEM, N 2 adsorption-desorption, NH 3 -TPD, and 29 Si MAS NMR techniques. Significant Findings The results showed that the particle size, textural and acidity properties, and the silicon coordination of the seed-derived products are strongly correlated to their corresponding seeds, exhibiting genetic effects. By investigating the crystallization kinetics, we speculated that the genetic effects should be attributed to the incomplete dissolution of the seeds. During the crystallization process, the incompletely dissolved seed fragments are directly incorporated into the product and serve as models. These models then require the final zeolites to grow according to their patterns, retaining and inheriting their original characteristics.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2024
·Vol. 48
·期 45
·19220-19228
·
IF 2.7
Peng Lu,Qianwen Hu,Kui Wang,Shiyong Chen,Zongxiao Li,Xinjie Chen,Chuang Xing,Yanhong Wang,Ce Du
The efficient CO2 conversion to light olefins through hydrogenation is a feasible strategy to achieve carbon neutrality goals. Herein, a series of bimetallic Zn–Zr/supports are synthesized by a conventional impregnation method. We demonstrate that different supports endow catalysts with various specific surface areas, pore sizes, chemical adsorption performances, and acid densities. The effects of different support-loaded Zn–Zr coupled with SAPO-34 on CO2 hydrogenation to light olefins are investigated systematically. The CO2 conversion of Zn–Zr/Q10-SAPO-34, Zn–Zr/Q50-SAPO-34, Zn–Zr/γAl2O3-SAPO-34, Zn–Zr/MgO-SAPO-34 and Zn–Zr/S-1-SAPO-34 is 11.4%, 9.2%, 24.0%, 8.8%, and 16.2%, respectively, with corresponding light olefin selectivity of 39.0%, 28.1%, 30.4%, 4.8%, and 14.7%, respectively. Significantly, γAl2O3 is more conducive to CO2 conversion, while Q10 tends to produce light olefins. This work provides an effective reference for support selection in CO2 hydrogenation to light olefins.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
·
2021
·Vol. 32
·期 8
·1598-1606
·
IF 1.838
Zhang Yangyang,Shao Chuan,Qin Dongling,Yang Gang
Solid acid-catalyzed dehydration of fructose to produce 5-hydroxymethylfurfural (5-HMF) has been a hotspot in biomass conversion research in recent years. In this study, a novel SAPO-34-based catalyst was prepared by consecutive steps of titanium doping, sulfuric acid impregnation, and sulfonic acid functionalization. Characterization of the catalyst with X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), BrunauerEmmett-Teller (BET), inductively coupled plasma optical emission spectrometer (ICP-OES), and acid-base titration revealed different pore structures and more acid content compared to SAPO-34. The catalyst was applied to the preparation of 5-HMF by dehydration of fructose, and the maximum yield (74.0%) of 5-HMF was obtained by reacting in dimethyl sulfoxide (DMSO) at 170 °C for 50 min. In addition, the applicability of the catalytic system to other substrates and the stability of the catalyst after five cycles were investigated, which are valuable for further probing on the concerned aspects.
研究领域:
化学工程
·
生物质能转化
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Lei Zhao,Ge Yang,Haocheng Hu,Yuhao Sun,Zhuang Ma,Peng Peng,Eng-Poh Ng,Peng Tian,Hailing Guo,Mintova Svetlana
The nanosheet SAPO-34 zeolite crystals with a diameter of 300 nm and a thickness of 50 nm using a new phosphorus source (pyrophosphoric acid, H 4 P 2 O 7 ) were synthesized. The roles of the pyrophosphate (P 2 O 7 4− ) species in the crystallization of SAPO-34 were elucidated. The results suggested that one P atom from the P 2 O 7 4− species participated in the formation of the CHA framework structure while the other P atom served as a crystallization control agent, facilitating preferential crystal growth in [100] crystal plane. The SAPO-34 nanosheets have silica-rich shell and phosphorus-rich core leading to superior catalytic performance in methanol-to-olefin reaction (MTO). The catalytic lifetime of the SAPO-34 nanosheets was significantly improved due to the larger amount of medium-strong surface acidity and short diffusion pathway in comparison to the conventional SAPO-34 catalyst synthesized in the presence of the classical phosphorus source (H 3 PO 4 ).
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
危险品化学品经营许可证（带存储）