APPLIED SURFACE SCIENCE
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2020
·
IF 6.182
Feitian Ran,Tianlin Wang,Siyu Chen,Yuyan Liu,Lu Shao
2D transition metal carbide (MXene) based flexible films have received increasing attention in the application of energy storage for portable and wearable electronic devices. However, the self-restacking caused by Van der Waals interactions between the layers lead to insufficient access to allow the electrolyte ions to contact the active material. Herein, we rationally utilized the freeze-drying technique to prepare MXene film electrode for alleviating its self-restacking and improving the electrochemical performances. Through freeze-drying treatment, the frozen solvent molecules were removed by sublimation, and alleviating the adverse effect of van der Waals forces and contributing to the enlarged layer space. The constructed freeze-dried MXene (f-MXene) films generate unique porous architecture, which can provide highly efficient ion diffusion and transport channels. Consequently, the typical f-MXene-10 film exhibit good specific capacitance (341.5 F g −1 /922.1 F cm −3 at 1 A g −1 ) and desired capacitance retention of 60.4% from 1 to 10 A g −1 . Moreover, the assembled asymmetric device delivered a maximal gravimetric energy density of 6.1 Wh Kg −1 , volumetric energy density of 16.4 Wh L −1 and a good capacitance retention of 89.3% after 10,000 cycles. The rationally designed synthesizing route has attractive promise to promote MXene materials for diverse energy and environmental applications.
研究领域:
材料科学
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能源存储
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柔性电子
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMISTRY
·
2021
·Vol. 39
·期 10
·2745-2754
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IF 6
Yinbing Tian,Zijie Tang,Yu Ru,Yuanyuan Wang,Liyi Dai
Main observation and conclusion Three diamines (1,8-diaminooctane/ p -phenylenediamine/biphenylenediamine) with different alkyl groups were used to synthesize the functionalized graphene networks. Pd as the common metal catalyst was used to explore the effects of alkyl types of diamines on anti-stacking, metal anchoring ability of functional graphene and hence the catalytic performance. The results were discussed by characterization of the material and its catalytic properties. All catalysts showed excellent catalytic performance on the Suzuki cross-coupling reaction with a high yield of up to 100%. The p -phenylenediamine and biphenylenediamine functionalized graphene with larger specific surface area was beneficial to improve the stability of the graphene catalyst and maintain good catalytic activity after 5 cycles. The Pd nanoparticles in 1,8-octanediamine materials have smaller size and a smaller loading with the same or even better catalytic performance than p -phenylenediamine, biphenylenediamine materials, due to the stronger electron donating ability of N of octanediamine than that of p -phenylenediamine.
研究领域:
材料科学
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催化化学
✓ 已验证
DOI
高影响因子
POLYMER BULLETIN
·
2024
·
IF 3.1
Yan Xin,Yang Jianming,Zhang Hexin,Yoon Keun-Byoung,Chen Min
The single-sited metallocene catalyst has attracted significant attention due to its high activity and application in olefin polymerization industry. In this work, we introduced a strategy of in situ modification of metallocene catalyst with pyrene through π–π stacking to study the effect in olefin polymerization. After activated by MMAO, the pyrene-modified metallocene catalyst exhibited high activities (up to 1333 kg mol −1 h −1 ) in ethylene polymerization, which was 1.9 times higher than that of the pyrene free catalyst system. This could be because the electron-donating ability of cyclopentene to the transition metal was enhanced through π–π interaction of pyrene with cyclopentene. The copolymerization of ethylene and 1-hexene was also studied. The pyrene-modified metallocene catalyst system performs with higher activity in the copolymerization with a lower monomer incorporation ratio. Density functional theory (DFT) calculations indicated the formation of π–π interaction between the Zr center with pyrene molecule leading to the increase in steric hindrance and electron density. Graphical abstract
研究领域:
高分子化学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2013
·Vol. 405
·期 26
·8587-8595
·
IF 3.659
Tang Yun-Yun,Wang Hou-Yu,Chen Lu,Li Si,Guo Chen-Gang,Fan Hui-Zhi,Cao Cheng-Xi,Fan Liu-Yin
We developed a novel polyacrylamide gel electrophoresis (PAGE) method to stack and separate human hemoglobins (Hbs) based on the concept of moving reaction boundary (MRB). This differs from the classic isotachophoresis (ITP)-based stacking PAGE in the aspect of buffer composition, including the electrode buffer (pH 8.62 Tris–Gly), sample buffer (pH 6.78 Tris–Gly), and separation buffer (pH 8.52 Tris–Gly). In the MRB-PAGE system, a transient MRB was formed between alkaline electrode buffer and acidic sample buffer, being designed to move toward the anode. Hbs carried partial positive charges in the sample buffer due to its pH below p I values of Hbs, resulting in electromigrating to the cathode. Hbs would carry negative charges quickly when migrated into the alkaline electrode buffer and be transported to the anode until meeting the sample buffer again. Thus, Hbs were stacked within a MRB until the transient MRB reached the separation buffer and then separated by zone electrophoresis with molecular sieve effect of the gel. The experimental results demonstrated that there were three clear and sharp protein zones of Hbs (HbA 1c , HbA 0 , and HbA 2 ) in MRB-PAGE, in contrast to only one protein zone (HbA 0 ) in ITP-PAGE for large-volume loading (≥15 μl), indicating high stacking efficiency, separation resolution, and good sensitivity of MRB-PAGE. In addition, MRB-PAGE was performed in a conventional slab PAGE device, requiring no special device. Thus, it could be widely used in separation and analysis of diluted protein in a standard laboratory.
Diagram of MRB-induced stacking in a slab PAGE. ( A ) arrangement of separation buffer (pH 8.01–9.55 Tris–Gly), sample buffer (pH 6.37–7.22 Tris–Gly), and electrode buffer (pH 8.21–9.05 Tris–Gly); ( B ) initial MRB formed between electrode and sample buffers for stacking of low-content Hbs in sample buffer under electric field; ( C ) MRB moving toward the anode and partly stacking of Hbs within the MRB; ( D ) quasi-complete stacking of Hbs via MRB closing to the separating gel; ( E ) separation of Hbs in a zone electrophoresis mode
研究领域:
生物化学
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医学检测
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蛋白质分析
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Jun-Yang Yan,Gui-Ping Cao,Chun-Yan Cao,Peng Gao,Mustapha Sani Shehu,Hui Lv,Alaaddin M. M. Saeed
This work investigated the loading of active metals on monolithic carrier NCNTs@FN through simulation and characterization and found that the active metal (Pd) had a stronger binding with NCNTs and a more uniform dispersion. Meanwhile, the π–π stacking effect between NCNTs and polystyrene (PS) molecules is more significant than that between PS and CNTs, making PS more easily adsorbed. Therefore, the highly active catalyst Pd-NCNTs@FN was prepared. The hydrogenation degree of Pd-NCNTs@FN catalyzed PS reached 92.7%, significantly higher than that of Pd-CNTs@FN (78.1%) under the same conditions. Uniform experiments on PS hydrogenation kinetics were designed. Power law and hyperbolic kinetic models were established, and the corresponding parameters were calculated. From the models, it was found that whether H2 concentration reaches a critical value determines whether H2 pressure affects the hydrogenation rate. In addition, the adsorption of PS is the rate control step in the reaction. The activation energy of Pd-NCNTs@FN catalyzed PS hydrogenation is 47.326 kJ/mol, which is lower than those of other traditional powder heterogeneous catalysts (50–55 kJ/mol), demonstrating the excellent activity of the catalyst.
研究领域:
催化化学
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材料科学
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反应动力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Hangqing Xie,Mengke Bai,Anqi Wang,Zi Chen,Feifan Chang,Jiadi Lian,Shiqing Xu
Triplet exciton is both a luminescence quenching factor and an important luminescence sensitization technology solution, which is widely concerned in the field of optoelectronic materials. Since X-ray excited triplet excitons are dissipated through various pathways, there are still huge difficulties in achieving efficient triplet sensitized emission. Here, the antenna ligand is regulated through the carboxyl group, increasing the steric hindrance between the conjugated groups and improving triplet-enhanced radioluminescence (RL) efficiencies of Tb 3+ . The lanthanide metal–organic frameworks (Ln-MOFs) formed by the coordination of Tb 3+ with mellitic acid (MA), pyromellitic acid (PMA) and trimesic acid (TMA) under low temperature preparation conditions. Among them, MA-Tb has a longer spacing between conjugated groups than PMA-Tb and TMA-Tb, and its triplet RL is relatively strongest, with a light yield of 28,000 photons MeV −1 . Mechanistic studies revealed that the RL efficiency of Ln-MOFs is related to the π-π stacking effect in the benzene ring. In addition, the application of MA-Tb in the field of X-ray detection was demonstrated. The RL intensity of MA-Tb has a good linear relationship with the X-ray dose rate, and the detection limit for X-ray reaches 82 nGy/s, which is 66 times lower than the typical medical imaging dose. These results will provide a universal strategy for the design of Ln-MOFs scintillator.
研究领域:
材料科学
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光电材料
·
放射学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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