Inorganic Chemistry Frontiers
·
2019
·Vol. 6
·期 11
·3097-3103
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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
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无机化学
·
催化
✓ 已验证
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2016
·
IF 3.349
Chen Liu,Lu Bai,Jianming Zhang,Deng Hu,Meng Li,Gaofeng Zeng,Yanfeng Zhang,Wei Wei,Yuhan Sun
Rapid synthesis and characterization of all-silica Deca-Dodecasil 3 Rhombohedral (DD3R) zeolite were systematically studied with (NH 4 ) 2 SiF 6 as silica source. The effects of gel recipe, synthesis temperature and time, seeding, aging and silica source were investigated systematically. Big DD3R crystals (50–150 μm) with various morphologies (hexagonal plate, polyhedron and rhombohedron) were obtained by tuning the synthesis temperature, time, seeding and aging. Compared with other silica sources, (NH 4 ) 2 SiF 6 is very reactive which enhances the nucleation and crystal growth of DD3R zeolite significantly. At 220 °C, highly crystalline DD3R was obtained in 12 h without seeding, which is the fastest synthesis up to now. Aging and seeding reduced the synthesis time substantially and led to smaller crystals. With the help of seeding and aging, pure DD3R crystals were obtained in 6 d at 100 °C, which opens the door to synthesis at low temperature and ambient pressure. Mixed silica sources can reduce the consumption of expensive (NH 4 ) 2 SiF 6 . Higher calcination temperature is required for the complete template removal of the big DD3R crystals obtained in this study, which hinders the diffusion of oxidation products from the template. Zeolites SGT and DOH are competing phases in the synthesis of DD3R. The introduction of Al into the mother liquor led to the formation of zeolite SGT.
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
MICROPOROUS AND MESOPOROUS MATERIALS
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2024
·
IF 4.8
Tianyu Bai,Jinquan Tao,Yijing Jia,Wenbin Huang,Rongpeng Yao,Xinan Xue,Yasong Zhou,Qiang Wei
In the research of directly synthesizing H-form ZSM-5, ammonium hydroxide is commonly used as an alkali source instead of NaOH to avoid multiple ion exchange steps. However, the volatile nature and the lack of structure-directing effect of ammonium hydroxide limit its application in practical. In this study, n -butylamine (NBA) was used as the main alkali source to directly prepare HZSM-5 zeolites with SiO 2 /Al 2 O 3 ratios ranging from 40 to 300 under traditional hydrothermal conditions. The influence of the amount of NBA, ethanol, seed, and pre-crystallization on the synthesis products was investigated under the condition of SiO 2 /Al 2 O 3 = 80. Theoretical simulation suggested that n -butylamine cations (NBA + ) play the most potent directing role in the formation of the MFI structure but could lead to difficulties in removal during calcination. The addition of ethanol as the zeolite growth modifier (ZGM) could decrease the usage of NBA and reduce the difficulties in calcination, and the addition of seed provided the conditions for initiating crystallization in the system that could not spontaneously nucleate. HZSM-5 with different SiO 2 /Al 2 O 3 ratios were prepared under the optimal crystallization conditions, and the as-synthesized samples exhibited superior textural and acid properties compared to commercial zeolite. Finally, the 1 L scale-up synthesis and MTP reaction were conducted to demonstrate the practicality of this economically and environmentally-friendly synthesis strategy.
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
MICROPOROUS AND MESOPOROUS MATERIALS
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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
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环境科学
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化学工程
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
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2022
·
IF 10.383
Xin Liu,Quanchao Zhang,Dou Zhao,Ruichen Bai,Yinjie Ruan,Binbin Zhang,Fangpei Li,Menghua Zhu,Wanqi Jie,Yadong Xu
Solution-grown hybrid perovskite, FAPbBr3, has attracted great attentions recently due to its inspiring optoelectronic properties and low-cost preparation method. However, challenges of solution growth for FAPbBr3 bulk crystals remain yet, such as uncontrollable crystalline morphologies, irregular shapes, and limited crystal sizes, which are attributed to the dense crystallization nucleus. In this work, we investigate the effects of growth conditions and seed behaviors on the crystallization quality and the yield of FAPbBr3 single crystals. First, the spontaneous nucleation is tailored by optimizing the precursor concentration and heating rate. Furthermore, the seeded crystals are introduced to solve the issues related to the morphology and the yield of single crystals. Based on the above-mentioned investigations, an optimized growth method, a seeded solution method, under a heating rate of 0.1 °C/h is proposed, and centimeter-scale FAPbBr3 single crystals with a very narrow FWHM of high-resolution X-ray diffraction rocking curves and a high yield of ∼100% of single crystals are obtained. The resulting FAPbBr3 single crystal exhibits a bulk resistivity of 3.42 × 109 Ω·cm and a superior ION/IOFF ratio over 104 under 405 nm light at a bias of 10 V. Finally, the pulse height spectra with an energy resolution of ∼21.4% are also achieved based on an AZO/FAPbBr3/Au detector, illuminated using an uncollimated 241Am@5.49 MeV α-particle source at room temperature. This modified seeded solution method shows great potential in preparing high-quality and high-yield perovskite single crystals.
研究领域:
材料科学
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晶体生长
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半导体物理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Siyu Gong,Ting Zhang,Bingguo Liu,Peng Liu,Yifan Niu,Zhenxing Yang,Yuhao Jin,Wang Chen,Guangxiong Ji,Shenghui Guo,Libo Zhang
The study introduces a microwave-assisted rutile seed crystal (RS) method to synthesise mixed-phase TiO 2 nanoparticles, controlling the rutile TiO 2 (TiO 2 -R) phase content ( γ R ) from 33.0 % to 99.3 % by adjusting the doping level of RS to 20.0 wt% in the metatitanic acid (MA). The sample, designated as MA-20, with the highest oxygen vacancy (O v ) concentration of 38.56 %, demonstrated over 99 % microwave absorption (minimum reflection loss ( R L ) −56.8 dB) and a heating rate of 0.836 °C/s under 2000 W and 20 g. RS enhanced the dielectric property of MA, facilitating phase transition from anatase TiO 2 (TiO 2 -A) to TiO 2 -R above 600 °C, with critical temperatures between 800 and 1000 °C. MA-20, with a surface area of 1.9226 m 2 /g and pore size distribution of 9.0851 nm, showed that higher RS doping levels promoted phase transition and grain growth, thereby enhancing the crystallinity and charge transfer efficiency. More than 50 % of MA-20 particles were under 10 nm, and 94 % were below 100 nm, confirming the synthesis of TiO 2 nanomaterials. MA-20 exhibited excellent electromagnetic wave storage and conversion properties. Adjusting microwave parameters and RS levels controls γ R , offering an efficient approach for preparing mixed phase TiO 2 catalysts, essential for semiconductor photocatalysis and overcoming TiO 2 -A limitations.
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
ACS Omega
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2024
·
IF 3.7
Jin Quan Tao,Yi Jing Jia,Yan Cui,Tian Yu Bai,Xi Nan Xue,Rong Peng Yao,Ya Song Zhou,Qiang Wei
The synthesis of zeolites through more efficient, environmentally friendly, and cost-effective methods was deemed significant in both industrial applications and academic fields. Conventional hydrothermal synthesis strategies have encountered difficulties in producing pure silica MFI zeolite (silicalite-1) under amine-free conditions. This was primarily attributed to the competitive growth of quartz, keatite, or magadiite during the crystallization process. In this work, it was found that the lack of nucleation ability was an important reason for the poor crystallization stability of the methanol solution. Well-crystallized silicalite-1 zeolites with uniform particle sizes were achieved through the cooperative guidance of methanol and seed crystals. Large-scale experiments with silicalite-1 zeolite demonstrated good reproducibility. Combined with the TG-IR and N2 adsorption–desorption results, it was observed that, when an extremely small amount of seed (0.97 wt %) was introduced, methanol could play a role as a crystallization promoter in the hydrothermal synthesis system. Furthermore, a lower alkaline-to-silica ratio and water-to-silica ratio were conducive to the progression of the crystallization process. In summary, this work presented a hydrothermal synthesis strategy for the synthesis of silicalite-1 zeolite in a methanol solution without the need for a large amount of seeds and provided an effective pathway for the low-cost, large-scale production of silicalite-1 zeolite.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2022
·
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
COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Haochuan Wang,Pan Feng,Xin Liu,Jiashun Shi,Chong Wang,Wei Wang,Hua Li,Jinxiang Hong
The ultra-early age strength of shotcrete with Portland cement-based materials in various supporting constructions is crucial for safety and engineering efficiency. However, concerns exist about the low strength and uncertain mechanism when using aluminum sulfate, the main component of most-used alkali-free accelerators. This study addresses these concerns by introducing ettringite seeds into the Portland cement system with aluminum sulfate. Significant improvement in ultra-early age compressive strength of mortar, i.e., 242 % at 6 h and 201 % at 8 h, was achieved by mere 1 % seed addition. Analyses of hydration heat, composition and microstructure demonstrate that the ettringite seeds mainly affect the mechanical performance by forming a more prolonged and coarser ettringite skeleton, rather than directly accelerating cement hydration. Such an enhanced skeleton was proved to establish stronger interactions between particles in the Monte Carlo simulations. Additionally, the synergistic effect of the ettringite skeleton and C–S–H gel on ultra-early age strength was also explored. These proposed strengthening mechanisms were verified by the C 3 S and equivalent CaCO 3 systems.
研究领域:
土木工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2022
·Vol. 19
·期 5
·2533-2544
·
IF 2.328
Changxi Jiang,Yinghua Zhuang,Jianjun Wang,Shengjun Liao,Lijuan Zhou,Shuang Li,Yunxia Zhao
Si 3 N 4 ceramics with high thermal conductivity and outstanding mechanical properties were prepared by adding β-Si 3 N 4 seeds and nanophase α-Si 3 N 4 powders as modifiers. The introduction of β-Si 3 N 4 seeds enhanced the growth of β-Si 3 N 4 grains. Owing to the interlocked structure induced by the β-Si 3 N 4 grains, the fracture toughness of Si 3 N 4 ceramics reached a high value of 7.6 MPa·m 1/2 ; also, the large-sized grains increased the contact possibility of Si 3 N 4 grains, improving the thermal conductivity of Si 3 N 4 ceramics (64 W/(m·K)). Because of the introduction of nanophase α-Si 3 N 4 , the flexural strength, fracture toughness, and thermal conductivity of the Si 3 N 4 ceramics increased to 754 MPa, 7.2 MPa·m 1/2 , and 54 W/(m·K), respectively. According to the analysis of the growth kinetics of Si 3 N 4 grains, the rapid growth of Si 3 N 4 grains was ascribed to the reduction in the activation energy resulting from the introduction of β-Si 3 N 4 seeds and nanophase α-Si 3 N 4 .
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
CEMENT AND CONCRETE RESEARCH
·
2025
·
IF 13.1
Hui Xie,Xin Liu,Haochuan Wang,Zhenqi Yu,Lijing Shao,Wei Wang,Jinxiang Hong,Chong Wang,Pan Feng
The use of aluminum sulfate (Al 2 (SO 4 ) 3 )-based alkali-free accelerators in shotcrete often impeded tricalcium silicate (C 3 S) hydration, leading to poor ultra-early strength development. To address this, a novel stage-wise kinetic control strategy was proposed to regulate the sequential formation of ettringite and C-S-H gel through the delayed addition of C-S-H nano seeds. The dosage of C-S-H nano seeds, delayed time, addition sequence of Al 2 (SO 4 ) 3 and C-S-H nano seeds were carefully examined in this study, and the effects of addition sequence on the hydration kinetic, hydration products, and pore structure of cement pastes were systematically investigated. Results demonstrated a significant enhancement in 6 h compressive strength, achieving a 35% increase when C-S-H nano seeds (4% dosage) were added 1 h after initial mixing compared to simultaneous addition. Hydration heat, XRD, TG, SEM, and BSE-EDS analyses revealed that the delayed addition promoted C 3 S hydration at later stages by staggering intensive ettringite formation and C-S-H gel precipitation, mitigating competition for calcium ions. This stage-wise approach facilitated C-S-H gel integration into the pre-constructed porous ettringite skeleton, refining the pore structure and enhancing ultra-early mechanical performance. These findings highlight an effective strategy to optimize hydration kinetics and strength development in shotcrete applications.
研究领域:
土木工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2019
·
IF 4.182
Xixi Ma,Xiaocao Wu,Jürgen Caro,Aisheng Huang
A seeding-free synthesis strategy was developed for the preparation of dense and phase-pure MFI zeolite membranes based on “like grows like” principle. Through covalent modification of the porous ceramic supports by using 1H,1H,2H,2H-perfluoroalkyltriethoxysilanes (POTS), the support surface was changed from hydrophilic to hydrophobic, which promotes the nucleation and growth of hydrophobic MFI zeolite membranes. Thin, well-intergrown and phase-pure MFI zeolite membranes, with a thickness of about 2.0–3.0 μm, can be facilely prepared on POTS-modified supports like Al 2 O 3 and TiO 2 at 175 °C for 24 h. No cracks, pinholes or other visible macroscopic defects are observed in the membrane layer. The MFI zeolite membranes were evaluated in the hydrophobic separation of 5.0 wt% ethanol/water mixture at 75 °C by pervaporation . The MFI zeolite membrane prepared on the POTS-modified TiO 2 disk shows high pervaporation separation for ethanol recovery. At 75 °C, a separation factor of 103 and total flux of 2.56 kg/m 2 h can be obtained, which is promising to extract bio-alcohols from the fermentation broth.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）