MATERIALS & DESIGN
·
2019
·
IF 5.77
Tingting Cheng,Siqi Li,Lan Xu,Adnan Ahmed
A modified electrospinning (MES), which consists of a copper mesh collector and an air pump placed behind it, was presented to fabricate nanofiber membranes (NFMs) with controllable large pore sizes by adjusting the MES parameters, such as copper mesh size, air velocity, applied voltage, flow rate and collecting distance. The controllable preparation mechanism of NFMs with large pore sizes was systematically investigated by experimental research and theoretical analysis. And the effects of the copper mesh grid dimensions, air velocity, applied voltage, flow rate and collecting distance on the pore sizes of NFMs were demonstrated. The results showed that NFMs with large pores produced successfully by the MES, and the pore sizes were all micrometer scale. And the optimal average pore size reached 14.45 μm 2 at the grid size of copper mesh of 4 mm×4 mm, the air velocity of 5 m/s, the applied voltage of 12 kV, the flow rate of 1.0 mL/h and the collecting distance of 18 cm.
研究领域:
材料科学
·
生物医学工程
·
纳米技术
·
组织工程
·
过滤材料
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2014
·Vol. 52
·期 17
·2442-2453
·
IF 3.245
Bingyan Jiang,Lei Zhang,Jie Yan,Qingquan Huang,Bing Liao,Hao Pang
A series of well-defined thermoresponsive graft polymers with different lengths and graft densities, poly(glycidyl methacrylate)- graft -poly( N -isopropylacrylate) (PGMA- g -PNIPAM), were successfully prepared by combination of controlled/living free radical polymerization and click chemistry. Effects of grafting length and density on the thermoresponsive behavior, aggregating mean diameter, and self-assembly morphology are systematically investigated. The thermosensitive characteristics of graft polymers in aqueous solution prove that the length and graft density had positive co-relationship with the lower critical solution temperature value and mean diameter of micelles as well as the size distribution, while the effect of graft length of polymers is more significant than that of density. Transmission electron microscopy analysis shows that the conformations of PGMA 45 - g -PNIPAM 20 and PGMA 45 - g -PNIPAM 46 with longer length and bigger grafting density in aqueous solutions are spherical nanoparticles with the increasing trend of the diameters, while that of PGMA 45 - g -PNIPAM (73, 50%) shows a spherical-like morphology, which indicates that the graft length and density have a significant effect on the mean diameter of micelle but not on the self-assembly morphology. These results reveal that to obtain desired thermoresponsive behavior and self-assembly morphology of functional polymers, it is essential to design and fabricate the structure of graft polymers with proper length and graft density. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52 , 2442–2453
研究领域:
高分子化学
·
材料科学
·
纳米医学
·
药物递送
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生物材料
·
智能响应材料
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2022
·
IF 4.598
Mingyuan Chen,Yaxin Lv,Peilin Wu,Liuyan Dong,Xingquan He,Lili Cui
To obtain highly active electrocatalyst for the whole electrochemical water splitting is of importance to generate hydrogen. Co(OH) 2 is used as electrocatalyst towards OER, however, the performance can be improved further. Usually, to construct the interface and adjust the electronic environment of electrocatalysts are regarded as powerful ways to improve the activity. Herein, CeO 2 -Co(OH) 2 sheets supported on copper foam (CF) are fabricated by electrodeposition method. The morphology and the electron structure of metals are adjusted by changing the molar ratio of Co to Ce, thus, resulting in different electrocatalytic activity. The optimal hybrids of CeO 2 -Co(OH) 2 exhibits lower overpotentials of 188, 269 mV to reach 10 mA cm −2 towards HER and OER, respectively, and good stability. Notably, it is found that the electroactivity is extremely superior to that of bare CF as well as the counterparts in the literature. Also, we try to employ M(OH) 2 (M = Fe, Ni) to substitute Co(OH) 2 to investigate the effect of species of hydroxides on the electron interaction between CeO 2 and hydroxides, the XPS results indicate that Ce and Co shows stronger electron interaction compared to other two control hydroxides. As electrocatalysts for alkaline full water splitting, CeO 2 -Co(OH) 2 requires a cell voltage of 1.62 V to drive 10 mA cm −2 . Experimental results prove the advantages of the electron engineering and morphology control.
研究领域:
材料科学
·
电化学
·
能源化学
·
纳米材料
·
催化化学
✓ 已验证
DOI
高影响因子
Laser & Photonics Reviews
·
2023
·Vol. 18
·期 1
·2300732
·
IF 11
Zhuowei Li,Ge Zhu,Shanshan Li,Wen Xu,Qingfeng Bian,Yan Cong,Ming He,Xixian Luo,Shuangyu Xin,Bin Dong
The burgeoning phosphor-converted near-infrared light-emitting diodes (pc-NIR LEDs) have important applications in special illumination and spectroscopy analysis. However, the development of efficient NIR-emitting phosphors with high performance is still a challenge. In this work, a chemical unit co-substitution strategy is proposed to realize the excitation transition regulation and successfully achieve high-performance NIR luminescence in Ca 3- y Na y Mg 1- y Sb 2- x Al 2+ y O 12 : x Cr 3+ (0 ≤ x ≤ 0.05, 0 ≤ y ≤ 1) garnet-type solid solution phosphors. Through the excitation transition modulation from the 4 A 2 ground state to the 4 T 1 ( 4 P) and 4 T 1 ( 4 F) excitation state, the excitation intensity at the blue light region is largely enhanced by 25.6 times. Moreover, the NIR-emitting efficiency and thermal stability are improved, with the optimal luminescence internal quantum efficiency of 90.6% and thermal stability of 97%@423 K, without any flux-assisted sintering or reduction atmosphere protection. The structure regulation induced small Stokes shift, weak electron-phonon coupling effect, and decreased non-radiative transition are responsible for the excellent NIR-emitting performance. Finally, the NIR pc-LED is fabricated with photoelectric efficiencies of 18.7%@100 mA and NIR output powers of 63 mW@100 mA, presenting potential applications in nondestructive internal defect detection, veins imaging, and night vision surveillance.
研究领域:
材料科学
·
光学工程
·
固体化学
·
发光材料
·
半导体器件
✓ 已验证
DOI
高影响因子
POLYMER
·
2019
·
IF 3.771
Wenbo Shen,Ling Wang,Gang Chen,Chunxin Li,Lanying Zhang,Zhou Yang,Huai Yang
A liquid crystalline epoxide was synthesized and its curing reactivity was compared with that of the conventional epoxy monomers . By utilizing the difference in curing reactivity between the liquid crystalline epoxide and non-liquid crystalline epoxy monomers, a coexistent system of polymer-dispersed and polymer-stabilized liquid crystal (LC) in the intelligent films can be obtained by two-step thermal curing method. If the later curing process was undertaken under an external electric field , the ordered microstructure of liquid crystalline epoxy polymer (LCEP) network can be implanted into the conventional epoxy resin. The competition of the anchoring effect on the LC molecules from the LCEP network and the conventional epoxy resin matrix was crucial to the electro-optical performance of the films. Moreover, the performance of the films can be adjusted by controlling the content of liquid crystalline epoxide and the external electric field applied during later curing. This approach can provide a facile route to regulate the electric-optical performance of polymer-dispersed liquid crystal films for practical applications.
研究领域:
材料科学
·
高分子化学
·
功能材料
·
光电工程
·
智能材料
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·Vol. 46
·期 12
·20173-20182
·
IF 3.83
Shujie Gai,Haifeng Zhu,Peixin Gao,Cheng Zhou,Zihui Kong,Maxim S. Molokeev,Zhiyong Qi,Zhi Zhou,Mao Xia
Currently, phosphor-converted LEDs (pc-LEDs) are revolutionizing the industry of plant growth lighting. To meet the requirements of this technology, phosphors with tunable photoluminescence , high thermal stability and luminous intensity are required. Herein, we found that the simple substitution of yttrium for lanthanum in La 2 MgTiO 6 :Mn 4+ (LMT:Mn 4+ ) system could satisfy above three criteria simultaneously. The photoluminescence properties can be regulated by continuously controlling the chemical composition of La 2-x Y x MgTiO 6 :Mn 4+ solid solution . The La sites are occupied by Y ions , causing a significant blue shift in the emission spectra which owing to the change of local crystal field strengthen. Meanwhile, the thermal stability and decay lifetimes are also varied due to the variation of local structure and band gap energy. The thermal stability of the material reaches 83.5% at 150 °C, which is better than the reported La 2 MgTiO 6 :Mn 4+ and Y 2 MgTiO 6 :Mn 4+ phosphors. The electronic luminescence (EL) of pc-LED devices using La 2-x Y x MgTiO 6 :Mn 4+ red phosphor is evaluated, which matching the absorption regions of plant pigments well, reflecting the superiority of the studied phosphors in plant growth lighting areas.
研究领域:
材料科学
·
光电子学
·
无机化学
·
农业工程
·
固体物理
·
发光材料
·
植物生理学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·Vol. 50
·期 4
·6598-6605
·
IF 5.2
Wei Peng,Jianglei Chang,Bin Wang,Zhen Liu,Genshui Wang,Shuxiang Dong
The ultrahigh piezoelectric coefficient (d 33 ≥ 1000 pC/N) exhibited by piezoelectric Pb(Zr,Ti)O 3 (PZT) ceramics not only captivates researchers but also holds considerable practical value across various applications. While significant progress has been made in enhancing piezoelectricity of PZT-based ceramics, novel mechanisms need to be proposed to explain the piezoelectric behavior of new systems with ultrahigh d 33 . In this study, we initially employ LiNbO 3 as an additive to enhance the piezoelectric properties of the Pb(Ni 1 / 3 Nb 2 / 3 )O 3 –PbZrO 3 –PbTiO 3 ceramics. and the optimal performance is achieved by incorporating 1.5 mol% of LiNbO 3 into the system, resulting in an ultrahigh d 33 ∼1178 pC/N ( d 33 * ∼1560 p.m./V (@ E = 5 kV/cm)). The corresponding mechanism for this superior piezoelectric response involves the AB-site co-doping effect, especially the ( Li Pb ′ − Nb Zr / Ti ∙ ) defect dipoles formed by the introduction of LiNbO 3 . In particular, the addition of LiNbO 3 leads to a more uniform distribution of domain sizes, thereby further enhancing the ultrahigh piezoelectricity. These findings pave the way for a deeper under-standing of the origin of ultrahigh piezoelectric properties and make substantial contributions to the advancement of piezoelectric materials for practical applications in electromechanical devices.
研究领域:
材料科学
·
功能陶瓷
·
压电材料
·
固态物理
·
电子显微学
·
介电材料
·
无机非金属材料
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Dewang Zeng,Yu Qiu,Min Li,Li Ma,Dongxu Cui,Shuai Zhang,Rui Xiao
Chemical looping redox cycle of oxygen storage materials offers a versatile platform to convert methane to value-added products in a clean and efficient manner. However, the highly dynamic nature of the oxygen diffusion process restrains the selective formation of the target products over a long reaction period. In this work, we show the oxygen storage materials-comprising of iron oxides and zirconium oxide support, with the nickel catalyst controllably deposited—that significantly enhanced the syngas selectivity. Mechanistic study indicated the oxygen releasing rate can be well controlled within a long reaction period by the specific spatial structure, demonstrating a new strategy to tune the oxygen diffusion in chemical looping process. Through the observed spatial effects, this work can be also extended to develop more oxygen storage materials for the other chemical looping applications, e.g. methane reforming, methane oxidative coupling, ethane oxidative dehydrogenation, etc .
研究领域:
催化化学
·
能源化学
·
材料化学
·
化学工程
·
多相催化
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2022
·Vol. 43
·期 9
·2443-2452
·
IF 12.92
Yaojia Cheng,Haoqiang Song,Jingkun Yu,Jiangwei Chang,Geoffrey I.N. Waterhouse,Zhiyong Tang,Bai Yang,Siyu Lu
The sluggish kinetics of oxygen reduction reaction (ORR) hinders the commercialization of Zn-air batteries (ZABs). Manipulating the electronic structure of electrocatalysts to optimize the adsorption energy of oxygen-containing intermediates during the 4e − ORR offers a practical route toward improving ORR kinetics. Herein, we designed a novel ORR electrocatalyst containing Co single atoms and nanoparticles supported by carbon dots-derived carbon nanoflowers (Co SAs/NPs CNF). Co SAs/NPs CNF possessed a very high ORR activity ( E 1/2 of the Co SAs/NPs CNF catalyst is 0.83 V ( vs. RHE)), and outstanding catalytic performance and stability when used as the air-electrode catalyst in rechargeable ZABs (152.32 mW cm −2 , 1000.58 mWh g Zn −1 , and over 1300 cycles at a current density of 5 mA cm −2 ). The Co SAs and Co NPs cooperated to improve electron and proton transfer processes during ORR. Theoretical calculations revealed that the presence of adjacent Co NPs optimized the electronic structure of the isolated Co-N 4 sites, significantly lowering the energy barriers for the rate-determining step in ORR (adsorption of *OOH) and thereby delivering outstanding ORR performance. This work reveals that the combination of supported single-atom sites and metal nanoparticles can be highly beneficial for ORR electrocatalysis , outperforming catalysts containing only Co SAs or Co NPs.
研究领域:
电化学
·
纳米材料科学
·
能源化学
·
催化化学
·
先进电池技术
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jingsheng Xu,Zhiyuan Wang,Runguo Zheng,Hongyu Sun,Yanguo Liu,Junhua You
Ni-rich cathodes especially with Ni content over 90 % are promising next-generation cathode materials for advanced high energy lithium − ion batteries. However, in comparison with Ni ≤ 80 % Ni-rich cathodes, these ultrahigh Ni-rich materials face more severe challenges in terms of harmful H2 − H3 phase transformations and structural degradation during cycling. Herein, we present a robust surface structure composted of defect-rich disordered structures and LiF/Li 2 SiO 3 coating for stabilizing the ultrahigh Ni-rich cathode LiNi 0.96 Co 0.03 Mn 0.01 O 2 (NCM96) by modification with (NH 4 ) 2 SiF 6 . The surface disordered structures including Li/TM mixing, spinel, and rock salt structure play a crucial role in inhibiting the irreversible H2-H3 phase transition and reducing lattice volume changes by lattice coherence effect. Moreover, the disordered surface in collaboration with the co-coating restrains the rapid growth of surface rock salt phase into the bulk, enhancing structural stability. The modified sample NSF-0.5 delivers a capacity of 238 mAh/g at 0.1C and maintains a capacity retention of 88.5 % at 0.5C after 100 cycles in half cell as well as 82.3 % at 1C after 300 cycles in full cell, significantly superior to the NCM96. The findings provide a simple and cost-effective surface modification strategy to enhance the structural stability and electrochemical performance of ultrahigh nickel cathodes for high-energy density LIBs.
研究领域:
材料科学
·
电化学
·
能源存储
·
锂离子电池
·
固态化学
·
表面工程
·
电池材料
✓ 已验证
DOI
高影响因子
CARBON
·
2024
·
IF 10.5
Ping He,Yu Zhang,Zhenguo Wang,Peng Min,Zhiming Deng,Lulu Li,Lvxuan Ye,Zhong-Zhen Yu,Hao-Bin Zhang
Graphene has been widely studied for its excellent properties of outstanding conductivity, strength , and flexibility. However, interlayer defects formed during the macroscopic assembly of graphene nanosheets will severely degrade the performance of graphene films. Herein, a strategy combined with trace carboxyl graphene oxide (GO), mild reduction, and chemical crosslinking is employed to minimize the interlayer defects for enhancing both the conductivity and mechanical strength of graphene films. The trace carboxyl feature of GO allows nanosheets to assemble orderly into highly oriented GO films . Subsequently, the mild chemical reduction preserves the highly oriented and packed microstructure. Coupling with further crosslinking by introducing conjugated molecules with pyrene terminal groups (1-pyrene butyric acid-1,6-hexane diamine, PHD) to provide extra π-π bonds, both the mechanical strength and conductivity of graphene films are improved to 548.4 MPa and 1.7 × 10 5 S m −1 , respectively. In addition, the graphene film with only ∼2 μm in thickness possesses an excellent electromagnetic interference shielding effectiveness (EMI SE) of ∼40 dB and a specific shielding effectiveness of up to 74 278 dB cm 2 g −1 in a wide frequency range of 8.2–40.0 GHz. Thus, this study provides an energy-saving fabrication route for mechanically strong, effective thermal management and EMI shielding films.
研究领域:
材料科学
·
纳米科技
·
高分子化学
·
功能材料
·
电磁屏蔽
·
热管理
✓ 已验证
DOI
高影响因子
ORGANIC ELECTRONICS
·
2019
·
IF 3.495
Xiangli Gao,Gaoyi Han,Yunzhen Chang,Ying Zhang,Honggang Li
To enhance the reduced graphene oxide hydrogels' capacitive performance, many modifiers are used to add doped element into the materials and improve the structure. The isomers of aminophenol which contain amino and hydroxyl groups on the benzene ring are employed as structure regulator and modifier to synthesize high-performance reduced graphene oxide hydrogels. The influences of preparation conditions including ratios of graphene oxide to aminophenol isomers, temperature, reaction times on the samples’ structure and properties have been investigated. The results show that the oligomer of o-aminophenol is formed on reduced graphene oxide sheets while the molecules of p, m-aminophenol are bound to the sheets; and that the hydrogel prepared in the presence of p-aminophenol has larger specific surface area, total pore volume , specific capacitance and good rate capability (74.0% of 427.0 F g −1 retains at 100 mV s −1 ) than other. The cells assembled by the optimized hydrogels exhibit the energy density of 14.07 Wh kg −1 at power density of 124.3 W kg −1 , and 4.96 Wh kg −1 at 6.78 kW kg −1 . Furthermore, 92.2% of initial capacitance can be retained after 20,000 cycles for the cells assembled by the optimal hydrogel. This kind of material may be found its use in energy storage field.
研究领域:
材料科学
·
纳米科技
·
电化学
·
能源存储
·
高分子化学
·
表面科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）