FUEL
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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
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2021
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IF 6.953
Min Luo,Kai Yang,Daotong Zhang,Chaozheng Liu,Pei Yang,Weimin Chen,Xiaoyan Zhou
Lignocellulose including cellulose , lignin, and hemicellulose could be extracted from wood, and has been used to prepare carbon electrode. However, complicated extraction greatly increases preparation cost. To achieve maximum utilization of lignocellulose and avoid complicated extraction, wood with porous structure and good mechanical strength is used as carbon precursor. Additionally, chemical activation is commonly used to create micropores to provide high capacitance, but it brings in natural structure destruction, and generation of wastewater during pickling. Moreover, to achieve desirable energy density, multi-step strategy with long duration is required for loading active materials on carbonized lignocellulose (CL). Herein, a one-step method is developed to prepare a free-standing hybrid CL electrode (CLE) by using Lewis acid in three aspects: (1) as structure protection agent, (2) as activating agent, (3) as active materials donor, which bypasses pickling and further avoids the generation of wastewater. Additionally, natural vessels in wood can not only provide large space for active materials loading, but also act as rapid ions diffusion way, simultaneously confining active materials detachment. Benefiting from the synergistic effect of porous structure and Lewis acid, this work not only makes full utilization of lignocellulose, but also makes CLE exhibit excellent performance in hybrid oxide supercapacitor.
研究领域:
材料科学
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能源技术
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2020
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IF 10.652
Lizhi Wang,Jiangfei Guo,Xiyuan Xiang,Yafei Sang,Jianhan Huang
Functionalized porous organic polymers (POPs) with high Brunauer-Emmett-Teller (BET) surface area ( S BET ) and unique porosity is promising while its facile synthesis remains a challenge. Herein, a novel synthesis strategy based on Schiff-base chemistry was developed and melamine was embedded as a rigid external cross-linker to construct a kind of novel functionalized POPs. The resulting melamine-supported polymers showed high S BET (645 m 2 /g) and total pore volume ( V total , 0.84 cm 3 /g) with unique hierarchical porosity, indicative of its outstanding CO 2 capture and Hg 2+ removal. Noticeably, the as-prepared sample TPE-TMC-2MA exhibited high CO 2 uptake of 153 mg/g and its ultramicropore volume ( V ultra , 0.16 cm 3 /g) played a positive role. In particular, the maximum capacity of Hg 2+ reached 392 mg/g, much higher than some other materials reported in the literature.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
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IF 5.1
Ruiji Zhang,Fangwei Guo,Wenchen Zhang,Fei Pan,Xing Zhang
Ceramics containing profiled fiber-like additives (nanotubes, whiskers, etc.) show high mechanical properties. However, the toughening mechanism is debated due to its complex multi-scale microstructure. In this work, ZrB 2 (Z)-20 vol%SiC(S) spiral fibers (ZS sf ) were prepared by liquid rope effect and non-solvent induced phase separation, while quantitative relation of mechanical properties and structure were investigated by using SEVNB with femtosecond lasers and in-situ 3D-XRM simulation. The ZrB 2 -SiC composites with hierarchy ZS sf exhibited a ∼60 % increase in fracture toughness (5.45 MPa m 1/2 ) compared with blank composites, while the toughening efficiency of the hierarchy ZS sf increased over 2 times compared to the 1D and 2D toughening additives. The ZS sf with a thin graphite-like layer and spiral structure with hierarchy pores provided a torsional release effect that changed brittle fracture to the pseudoplastic fracture, where topological interlocking of 3D crimped structure hindered rapid cracking propagation. Additionally, the enhanced toughness was attributed to the uniform reconstruction of the stress field induced by hierarchical inner pores. The preserved 3D topological interlocking and uniform stress reconstruction lead to the highly stable fracture toughness of the ZS sf composites up to 1500 °C.
研究领域:
材料科学
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力学
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陶瓷工程
✓ 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）