CATALYSIS TODAY
·
2024
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IF 5.2
Longyu Wang,Na Wang,Suohe Yang,Guangxiang He,Haiyan Liu,Xianghai Meng,Chunming Xu,Zhichang Liu,Haibo Jin
A diverse suite of Zn-SAPO-34 catalysts was synthesized employing three distinct methodologies for the incorporation of zinc species: thermal ion exchange, wet impregnation, and physical mixing. The catalysts were characterized using various analytical techniques including XRD, FT-IR, BET, SEM, XRF, XPS, NH 3 -TPD, and Py-IR, to elucidate the crystal structure, morphology, surface acidity, and the presence of zinc species within the catalysts. The study showed that the method of zinc introduction markedly impacts the physicochemical properties of the catalysts. Different approaches to introducing zinc species significantly influence the acid strength and type on the catalyst surface, with variations in the existing states of zinc across the catalysts. Specifically, zinc species introduced via thermal ion exchange coexist as ZnOH + and ZnO within the catalyst, whereas those from wet impregnation and physical mixing are individually present as either ZnOH + or ZnO. Furthermore, the study examined the catalytic performance of these Zn-SAPO-34 catalysts in the dehydration of fructose to produce 5-hydroxymethylfurfural (HMF). Catalysts prepared via thermal ion exchange exhinited superior performance, achieving an remarkable HMF yield of 94.6 %. Additionally, in situ infrared technology was used to investigate the effect of zinc species introduction on the fructose dehydration process, indicating suggesting that the introduction of zinc species enhances the transformation of fructose molecules.
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 Science & Technology
·
2021
·Vol. 12
·期 3
·894-905
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IF 6.119
Jihui Yao,Yuzi Rong,Zeyan Gao,Xiaohua Tang,Fei Zha,Haifeng Tian,Yue Chang,Xiaojun Guo
To introduce a hierarchical porous structure into SAPO-34 zeolites and adjust their acid properties and crystalline size, a series of Zr-modified SAPO-34 zeolites (Zrx-SAPO-34 (x = 0.25, 0.50 and 0.75)) with hierarchical porous structure were synthesized by hydrothermal crystallization using palygorskite as a silicon and partial aluminum source, morpholine and tetraethylammonium hydroxide as organic structure directing agents and UiO-66 as a co-template agent. The obtained catalysts were characterized via XRD, SEM, TEM, EDX, N2-adsorption–desorption, NH3-TPD, FTIR, Py-IR, XRF, 29Si MAS NMR and TG analyses. The catalytic performance of Zrx-SAPO-34 in the methanol-to-olefin (MTO) transformation was investigated in a fixed bed reactor. The introduction of a hierarchical porous structure effectively enhanced the diffusion and mass transfer of the reactants/products, prolonging the catalytic lifetime. Additionally, the optimization of the acidity dramatically improved the selectivity for light olefins. Under the reaction conditions wherein the reaction temperature was 400 °C, the feed of WHSV was 2.0 h−1, the mass of the catalyst was 0.5 g and at atmospheric pressure, the Zr0.50-SAPO-34 zeolites exhibited optimum catalytic performance, where the methanol conversion was 100%, the light olefin selectivity was 98.66% and the catalytic lifetime was more than 1500 min.
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
JOURNAL OF SOLID STATE CHEMISTRY
·
2025
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IF 3.5
Lei Chen,Wenjie Yao,Xu Chen,Gang Yang
The Cu-Ce modified SAPO-34/ZSM-5 (S-Z) composite molecular sieve catalysts were synthesized via a stepwise crystallization process using triethylamine (TEA) and tetraethylammonium hydroxide (TEAOH) as dual templates. This method significantly reduces the crystallization time from 24 hours to 12 hours. The incorporation of metal ions alters the structure and acid strength of the molecular sieves, thereby decreasing the rate of coke formation during the reaction, which in turn extends the catalyst's lifetime. Experimental results demonstrated that the catalyst's lifetime increased progressively with the addition of Ce. In the methanol-to-olefin reaction, the catalytic lifetime of the S-Z/Cu 0.05 -Ce 0.05 samples reached 1440 mins, approximately 480 mins longer than that of the S-Z samples, while maintaining a selectivity for low-carbon olefins at around 89.6%.
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Xiangbo Song,Jun Yue,Yuting Zhu,Chengyan Wen,Lungang Chen,Qiying Liu,Longlong Ma,Chenguang Wang
Efficient and one-pot conversion of biomass-derived carbohydrate into highly value-added 5-hydroxymethylfurfural (HMF) is a crucial reaction step for the valorization of biomass resources toward bio-based chemicals and fuels. In this work, a series of Sn/SAPO-34 catalysts were prepared through impregnation and evaluated in glucose conversion to HMF. The physicochemical properties of Sn/SAPO-34 catalysts were systematically characterized by SEM, XRD, N2 physisorption, XPS, solid-state 119Sn, 29Si, and 31P NMR, XRF, UV–vis, NH3-TPD, and pyridine-FTIR techniques. It was demonstrated that controlling the Sn loading amount could facilely adjust the acid strength and acid amount of the SAPO-34 zeolite. The incorporation of Sn species could induce the formation of a tetrahedrally coordinated Sn4+ site and Sn-OH site to improve the amounts of Brønsted and Lewis acid sites of the catalyst. However, modification with sufficiently high Sn loading could decrease the acid strength and performance of the catalyst owing to its structure damage. The 5%Sn/SAPO-34 catalyst (i.e., Sn loading calculated based on the mass ratio of SnCl4·5H2O as a precursor to the parent SAPO-34) was found to exhibit the superior catalytic performance under mild conditions and could afford an HMF yield of 64.4% at 98.5% glucose conversion in a biphasic 35 wt % NaCl-H2O/tetrahydrofuran (THF) system at 150 °C within 1.5 h. Additionally, a catalytic reaction pathway was proposed, involving the adsorption of glucose molecules by the −Cl group on the catalyst via a hydrogen bond, followed by glucose isomerization to fructose over the Lewis acid Sn4+ and Al3+ sites and, finally, fructose dehydration to HMF catalyzed by the Brønsted acid Sn-OH and Si-OH-Al sites. The activity of the catalyst decreased due to the leaching of the active site Sn after several consecutive cycles. This work provides insights into the improvement in the Sn-containing zeolite catalyst for tandem conversion of glucose to HMF.
研究领域:
化学工程
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催化
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可再生能源
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
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IF 8.035
Quanhua Wang,Wenwen Zhang,Xiaosen Ma,Yanchao Liu,Lichen Zhang,Jiajun Zheng,Yan Wang,Wenlin Li,Binbin Fan,Ruifeng Li
Hierarchical SAPO-34 zeolites with tunable porosity were hydrothermally synthesized by modulating the Si/Al molar ratios of the gel precursors, and the morphologies of SAPO-34 crystals gradually evolve from well-dispersed ultra-small nanocrystals to compactly polycrystalline aggregates, and to analogous polycrystallinites but adhered with minute amorphous debris by increasing the Si/Al ratio ranging from 0.20 to 0.67. The catalytic tests during methanol-to-olefins (MTO) reaction indicate that the Hier-SAPO-34-0.20 (Si/Al = 0.20) catalyst constructed by loosely nano-sized crystals centered at 50 nm presents prominent catalytic performances with about 2.5 times prolonged catalytic longevity and around 10 % improvement for the selectivity toward light olefins (ethylene and propylene) as compared to a reference catalyst. More interestingly, when Hier-SAPO-34-0.20 catalyst was in situ pretreated with NH 3 flowing, the selectivity of light olefins can be greatly increased by 18.1 % at the initial stage and the corresponding even selectivity with time-on-stream can be elevated by 6.9 %. It founds that in situ NH 3 -poisoned catalysts with improved light olefins selectivity are also suitable for ZSM-5 zeolite. These results reveal that the weakened strong acid sites modified by NH 3 -poisoning play a pivotal role in suppressing the undesired hydrogen transfer reactions and thus giving a high selectivity for light olefins. This work highlights the importance of acidity fine-tailoring by in-situ NH 3 -poisoning strategy on hierarchical zeolites for the improvement of light olefin selectivity, which would be valuable guidance for industrial applications.
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
ACS Applied Materials & Interfaces
·
2024
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IF 8.3
Quanhua Wang,Weijiong Dai,Yi Dai,Meng Pan,Yanchao Liu,Lichen Zhang,Jiajun Zheng,Xuguang Liu,Ruifeng Li,Luoning Ma,Hu Wang,Yuhao Zong
It is well known that low-silica SAPO-34, with an extra porosity (meso- and/or macropores) system, affords excellent catalytic performance in the methanol-to-olefins (MTO) reaction, while the direct synthesis of low-silica SAPO-34 with a hierarchical structure is difficult to achieve, principally because the crystal impurities are usually formed under a low silica content in a gel precursor. Herein, low-silica SAPO-34 nanocrystals were successfully fabricated for the first time by constructing an isomorphous core–shell structure in an epitaxial growth manner. In which, low-silica, ultrasmall nanosquare-shaped SAPO-34 crystals with the same growth orientation along the (100) crystal plane compactly grow on the monocrystal SAPO-34 cores. Crucially, the external surface acid properties of the core SAPO-34 with the Si-rich outer layer are effectively modified by the low-silica SAPO-34 shell. Furthermore, the growth process and Si-substitution mechanism of the shell zeolite were comprehensively investigated. It was found that with the prolonged crystallization time, more and more coordinated Si(4Al) and Si(3Al) structures via two substitution mechanisms (SM2 and SM3) are generated in the nanocrystalline SAPO-34 shell, which endow moderate acidity of the core–shell SAPO-34. Compared to the uncoated SAPO-34, the core–shell SAPO-34 performs a longer lifespan and a higher average selectivity of light olefins (ethylene plus propylene) when applied to the MTO reaction, which is attributed to the positive effects of the luxuriant interstitial pores offering a fast diffusion channel and the moderate acid density depressing the hydrogen transfer reaction of light olefins. This work provides new insights into the fabrication of low-silica SAPO-34 nanocrystals, which are based on the rational design of the isomorphous core–shell zeolite.
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
PubMed
高影响因子
Journal of Environmental Sciences
·
2019
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IF 3.556
Yue Ma,Xiaodong Wu,Junyu Zhang,Rui Ran,Zhichun Si,Duan Weng
Selective catalytic reduction (SCR) with urea catalyzed by Cu-SAPO-34 is an effective method to eliminate NO x from diesel exhaust . However, urea-related deposits may form during cold-start and urban driving due to low exhaust temperatures. The activity of Cu-SAPO-34 at 175°C is significantly degraded by urea exposure, and 300°C is required for regeneration. Through in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature-programmed hydrolysis studies, the dominant stable deposit at 175°C is identified as biuret, which can be eliminated at 300°C. The urea-derived deactivation and regeneration mechanisms of Cu-SAPO-34 were compared with those of anatase-supported catalysts.
研究领域:
催化
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环境工程
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2021
·
IF 5.062
Weile Li,Mengzhu Li,Huai Liu,Wenlong Jia,Xin Yu,Shuai Wang,Xianhai Zeng,Yong Sun,Junnan Wei,Xing Tang,Lu Lin
The economic and highly efficient synthesis of γ-valerolactone (GVL) is being increasingly focused due to its wide applications in solvent, chemical, and fuel. Herein, a range of SAPO-34 supported zirconium phosphate (ZPS-X) catalysts were prepared for a facile one-pot conversion of furfural (FF) to GVL through a series of cascaded reactions involving transfer hydrogenation, etherification, alcoholysis and esterification. The introduction of zirconium phosphate renders the formation of relatively strong Lewis acid sites, and the amount of Lewis (L) and Brønsted (B) acid sites of ZPS-X catalysts could be modified by adjusting the molar ratio of Zr to P (Zr/P ratio). Specifically, ZPS-1.0 having an appropriate Zr/P ratio with relatively strong L acid sites exhibited superior activity and selectivity for the production of GVL from FF.
研究领域:
催化
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化学工程
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材料科学
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可再生能源
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
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IF 9
Aicheng Song,Zhitao Han,Xiao Yang,Mengjing Zhang,Xi Wu,Zelu Zhou,Dong Liu,Dong Ma
The high energy consumption associated with solution regeneration in amine-based CO 2 capture processes remains a major challenge for large-scale carbon capture and storage (CCS) applications. However, the addition of solid acid catalyst accelerates the slow CO 2 desorption process while reducing the energy consumption for regeneration of the amine-rich solution. Herein, we innovatively developed Mn 3 O 4 -modified SAPO-34 catalysts via impregnation, demonstrating exceptional efficacy in reducing energy consumption for CO 2 -rich monoethanolamine (MEA) solution regeneration. Mn 15 -SAPO catalyst exhibited excellent performance in catalytic desorption tests using a 5 M CO 2 -rich MEA solution at 90 °C, achieving a 31.0 % increase in CO 2 desorption rate, a 133.3 % increase in CO 2 desorption amount, and a 57.1 % reduction in solution regeneration heat duty compared to the non-catalytic process. Comprehensive characterization revealed that the optimized Mn 15 -SAPO catalyst featured abundant strong acidic sites, optimal mesoporous structure, and the redox activity of Mn 3+ /Mn 4+ species. FTIR and 13 C NMR analysis confirmed the catalytic accelerating effect of catalysts on the conversion of intermediates. A possible reaction mechanism for the catalytic desorption of CO 2 over Mn x -SAPO catalysts was discussed. Additionally, the cycling stability of Mn 15 -SAPO catalyst was also evaluated. This work demonstrated the potential of Mn 15 -SAPO catalyst in enhancing the efficiency of the amine CO 2 capture process and reducing energy consumption, which was conducive to the application of industrial CO 2 capture.
研究领域:
能源与燃料
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环境科学
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催化
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化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Greenhouse Gases-Science and Technology
·
2022
·Vol. 12
·期 2
·305-320
·
IF 2.518
Zichen Liu,Shuman Xu,Jing Hao,Lina Song,Mingben Chong,Dang-Guo Cheng,Fengqiu Chen
The conversion of CO 2 into high-value chemicals has drawn a great deal of consideration, of which the most ideal product is lower olefins. However, the modified Fischer–Tropsch (F-T) synthesis with CO as an intermediate shows poor selectivity for lower olefins. Here, a list of bifunctional catalysts consisting of SAPO-34 zeolites with adjustable silicon contents and In 2 O 3 /ZrO 2 were synthesized. In the reaction process, CO 2 is first hydrogenated to methanol over an In 2 O 3 /ZrO 2 catalyst, and then the generated methanol rapidly diffuses to the adjacent zeolite catalyst to react to lower olefins. The selectivity of lower olefins (88.3%) and conversion rate of CO 2 (23.3%) was achieved over In 2 O 3 /ZrO 2 and SAPO-34-0.05 at 633 K, a gas hourly space velocity (GHSV) of 4500 ml·gcat –1 ·h –1 , and H 2 /CO 2 /Ar = 3:1:1. The catalytic performance remained stable after 50 h of reaction. Characterization analysis showed that Si content affected the content of Brønsted acid sites (BAS) and morphology of SAPO-34, resulting in different distribution of reaction intermediates. Tetramethyl-benzenes, as important intermediate species, had a slower conversion rate on the SAPO-34 with low Si content and nanosheet morphology, which led to high lower olefins selectivity. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.
研究领域:
催化
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化学工程
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材料科学
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环境化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Qibo Liu,Jingce Bi,Zhouxiao Zhai,Wen Tian,Ningning Liu,Xia Zhang,Zhuopeng Wang,Huanying Zhou,Yide Han
Rate-limiting mass transfer is a critical issue for using iron-based catalysts supported by zeolites to activate peroxydisulfate (PDS) in the field of advanced oxidation processes (AOPs). In this study, hierarchically porous Fe-SAPO-34-DGC was synthesized via combing in-situ encapsulation method with dry gel conversion (DGC) technology. Tetracycline (TC) was applied as a model pollutant, about 91.5% TC in Fe-SAPO-34-DGC/PDS system can be degraded within 90 min, while it can be achieved for about 150 min in Fe-SAPO-34-HT/PDS system. Meanwhile, the degradation rate constant of Fe-SAPO-34-DGC/PDS system is 0.02391 min -1 , which is approximately 1.6 times higher than that of Fe-SAPO-34-HT/PDS system. The excellent catalytic performance of Fe-SAPO-34-DGC is caused by well dispersed iron-oxide species (the size about 1.47 nm) in cha cage and nanoplate-like morphology as well as mesoporous structure, resulting in the generation of more active sites for PDS activation and faster mass transfer and easier access to active sites. Moreover, the characterized results indicate that the absence of Si(3Al) species is favorable of the formation of nanoplate-like morphology, further leading to the formation of the mesoporous structure because of stacking. Besides, iron-oxide species in Fe-SAPO-34-DGC are confined in cha cage that can effectively keep back its leaching. Furthermore, the possibility of membrane reactor established by Fe-SAPO-34-DGC for practical environmental water treatment was evaluated. Therefore, this method combing in-situ encapsulation method with dry gel conversion technology provides an alternative pathway for construction of iron-based catalysts supported by zeolites to remove organic pollutants through PDS activation.
研究领域:
环境科学
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催化
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材料科学
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化学工程
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高级氧化工艺
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2021
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IF 5.455
Qitong Cheng,Benxian Shen,Jichang Liu,Hui Sun,Di Wu,Lei Jiang,Peikun Yan,Xin Pu,Suhui Ou,Jigang Zhao
An alternative and promising route for the production of light olefins which realizes the objective of effective resource usage is the coupling conversion of n -hexane-methanol. The SAPO-34@ZSM-5 core-shell composite has been designed and fabricated by the steam-assisted crystallization (SAC) method for boosting the n -hexane-methanol synergies. SAC avoids the undesired phase transformation/dissolution of SAPO-34 caused by exposure to harsh basic conditions of the ZSM-5 precursor solution. In comparison with the nanosized ZSM-5 or physical mixture, the SAPO-34@ZSM-5 core-shell zeolite demonstrates a 32–38 wt% increase in the light olefin selectivity, a 28–67 wt% increase in the n -hexane conversion, and an 89–143% improvement in the catalyst lifetime under identical reaction conditions. With the aid of GC-MS analysis of carbonaceous deposits in spent catalysts, higher polymethylbenzenes concentration and lower polycyclic aromatic hydrocarbon (PHA) concentration are obtained from the extracted species of spent SAPO-34@ZSM-5 in comparison with that of other samples, which suggests the aromatic-based route to light olefins is enhanced and the carbonaceous deposition is slowed down. The core-shell configuration of the SAPO-34@ZSM-5 composite diminishes the diffusion rate of methanol towards the SAPO-34 core layer and increases the coupling of n -hexane derivatives with methanol in the hydrocarbon pool (HCP) route. The decreased number of acidic sites on the external surface of the SAPO-34 core layer may also be accounted for the inhibited carbon deposition.
研究领域:
化学工程
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催化
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材料科学
✓ 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）