RARE METALS
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2024
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IF 9.6
Li Zhao-Yang,Zhao Wei-Jun,Sun Yu,Zhou Bing,Feng Yue-Zhan,Liu Chun-Tai
The pressing demand for ultrathin and flexible shields to counter electromagnetic interference (EMI) has sparked interest in Ti 3 C 2 T x MXene materials due to their exceptional electrical conductivity, tunable surface chemistry, and layered structure. However, pure Ti 3 C 2 T x MXene films often lack the mechanical properties required for practical engineering applications, and traditional reinforcement methods tend to reduce electrical conductivity. This work demonstrates an effective strategy to enhance the alignment and densely packed layered structure of Ti 3 C 2 T x MXene films by regulating the acidity and alkalinity of Ti 3 C 2 T x MXene aqueous solutions. This approach simultaneously improves mechanical strength and electromagnetic interference shielding effectiveness (EMI SE). Compared with original Ti 3 C 2 T x MXene films, MXene films modified with ammonia solution (NH 3 ·H 2 O) via OH − show a significant improvement in tensile strength (27.7 ± 1.9 MPa). Meanwhile, MXene films treated with hydrochloric acid (HCl) via H + reach an even higher tensile strength of 39 ± 1.5 MPa. Moreover, the EMI SE values of the treated MXene films increase significantly, each reaching 66.2 and 58.4 dB. The maximum improvements in EMI SE values for the acid- and alkali-treated samples are 17.9% and 4%, respectively. In conclusion, the simultaneous enhancement of mechanical strength and EMI shielding efficacy highlights the potential of acid- and alkali-treated Ti 3 C 2 T x MXene films for applications in ultrathin and flexible EMI shielding materials. Graphical abstract
研究领域:
材料科学
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电子工程
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2022
·Vol. 46
·期 35
·16752-16763
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IF 3.925
Kai Guo,Aizeng Ma,Zijian Wang,Jinzhi Li,Bingfeng Wu,Tong Liu,Dadong Li
The design of various hierarchical structures and morphologies of ZSM-22 zeolite catalysts is attempted through a post-treatment using different concentrations of NaOH and subsequently treating with HCl solution including fluosilicic acid (H2SiF6) and then loading Pt on their surfaces. The effects of samples on textural characters, acidity, as well as n-heptane catalytic hydroisomerization evaluation were examined. The formation process of the hierarchical structures was further investigated. Test and evaluation results indicated that samples treated with 0–0.5 M NaOH and subsequently treated with 6.0 M HCl and 0.1 M H2SiF6 were much more controllable and reasonable due to the better structure-activity relationship of the catalyst by changing crystal morphologies and introducing hierarchical structures. Indeed, PZH-0.3 exhibited 81.1% of the highest n-heptane conversion and 76.4% of total i-heptane yield in the n-heptane catalytic hydroisomerization process at 260 °C, PZH-0.5 displayed 13.6% of the maximum multi-branched i-heptane yield, which was above 104.1% in comparison with PZ-0 at 320 °C. Moreover, PZH-0.3 presented the highest n-butane yield, which possessed a proportion of 65.9% in the butane component of cracking products at 340 °C and improved an average of 16% and 22 times when utilizing PZ-0 and Pt/ZSM-5 catalysts. Additionally, the mechanism of the reaction process is briefly depicted according to the distribution of the reaction products. The regulation of zeolite both on crystal morphologies and pore hierarchy has obvious advantages in the hydroisomerization process, which can improve the composition of multi-branched isomers with high octane number effectively as well as supply raw materials for the chemical industry.
研究领域:
催化化学
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石油化学工程
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材料科学
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DOI
高影响因子
CARBOHYDRATE POLYMERS
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2025
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IF 12.5
Zhicheng Cai,Jianfeng Lu,Ziqi Dong,Hong Wang,Qiang Li,Lin Lin,Chenghui Wang,Bin Zheng,Xiangzhao Mao,Changhu Xue
Chitin, a high-value biopolymer derived from crustacean shells, generally requires harsh chemical decolorization to achieve acceptable purity and appearance. Herein, we developed a green extraction method for chitin using atmospheric pressure plasma jet pretreatment combined with acid–base processing. Chinese mitten crab shells were subjected to different sequences and concentrations of hydrochloric acid (HCl) and sodium hydroxide (NaOH) treatments, with and without plasma pretreatment. Structural and physicochemical characterizations were performed via FTIR, SEM–EDS, AFM, XPS, NMR, XRD, TGA, and molecular weight analysis. The results indicated that when the acid–base concentrations were ≥2-M HCl and ≥1-M NaOH, plasma pretreatment (PJ–HN) enabled the release of high-purity chitin without the need for chemical decolorization. The chitin obtained exhibited comparable crystallinity (64.58 %), thermal stability (DTG max = 402.9 °C), and molecular weight (6.89 × 10 5 g/mol) to commercial chitin. Moreover, the PJ–HN samples retained high acetylation degrees and showed enhanced surface roughness, indicating improved functional potential. The antibacterial test confirmed that it possesses broad-spectrum antibacterial activity. The present study demonstrates that plasma-assisted extraction can serve as an eco-friendly and efficient alternative to conventional chemical methods in crustacean chitin processing.
研究领域:
生物高分子
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绿色化学
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材料科学
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生物技术
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纳米技术
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DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL RESEARCH
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2022
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IF 1.097
Ying Wang,Fei Du,Chunyan Wang,Jiaqiang Zhao,Haizhu Sun,Chuanyin Sun
High-performance hierarchical cheese-like C-ZSM-5 nanocrystals are successfully prepared by acid–base treatment and are evaluated for oxidative desulfurization of dibenzothiophene. The acid–base treatment can generate a large number of Si-OH bonds and an open-mesoporous structure, which is conducive for the dispersion of TiO2 and also for the transport of dibenzothiophene and its oxidation products simultaneously. The catalytic results indicate that the hierarchical cheese-like C-ZSM-5 nanocrystals are highly active catalysts for the oxidative desulfurization of dibenzothiophene due to open mesoporosity. Complete conversion was obtained within 80 min at 338 K. The excellent performance is due to the large number of active framework sites and open mesopores generated by post-processing.
研究领域:
化学工程
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材料科学
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DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2023
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IF 9.5
Xiao Deng,Zhaohuan Mai,Haohan Wan,Junyong Zhu,Hideto Matsuyama,Shushan Yuan,Gang Zhang,Xiujing Xing,Bart Van der Bruggen
Developing a new generation of polymer membranes with switchable pores for multiple separation processes remains challenging due to the lack of materials with reversible and adjustable chemical structures . Herein, amine oxide units were introduced in the chains of poly (arylene ether sulfone) via oxidizing the tertiary amine (TA) in poly (arylene ether sulfone)/amide tertiary amine (PAES/ATA) copolymer , and then served as switches to tune the pores of the prepared membranes. The smart membranes could be reversibly tuned between loose nanofiltration mode with water permeance of 178 L m −2 h −1 bar −1 and dye (e.g., Rhodamine B) rejection of 95%, and ultrafiltration mode, with water permeance of 650 L m −2 h −1 bar −1 and dye rejection of 55%, by cyclic acid-alkali treatment. The mechanism of the switchable pore size was elucidated by dissipative particle dynamics (DPD) simulations, and the results were in good agreement with experimental results. This study provides a novel and facile route to fabricate functional membranes with reversibly tunable and highly efficient filtration performance, which could be applicable to multiple separations.
研究领域:
材料科学
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化学工程
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膜技术
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DOI
高影响因子
危险品化学品经营许可证（带存储）