APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Xiong Wang,Zhenyou Li,Xiaoyu Han,Zhengang Han,Yongxiao Bai
Porous organic Polymers (POPs) can not only exhibit high specific surface area and pore volume, but also tunable pore size distribution. Herein, copolymers of 2-hydroxyethylmethylacrylate (HEMA) and divinylbenzene (DVB) with specific pore structure were synthesized via a dispersion polymerization strategy, and then immobilized metallocene catalysts with well-defined pore structure were obtained on the produced POP supports. The nitrogen sorption and Gel permeation chromatography (GPC) results demonstrate that the pore structure of the immobilized metallocene catalyst is highly dependent on the pore structure of the POPs , and the pore structure of metallocene catalysts or the POPs has a significant influence on the molecular chain growth of the produced polyethylene. By tuning the distribution of the active species scattered in the micro- and the narrow meso-pore range (roughly ≤4 nm), the chain growth of the polyolefin can be tailored effectively during the polymerization process, although differential scanning calorimetry (DSC) and temperature rising elution fractionation (TREF) results show that the chemical composition distributions (CCDs) of produced PE from the POPs-supported metallocene catalysts are not determined by polymerization activity or molecule chain length, but mainly by the active site species scattered in the supported catalysts. Scanning electron micrograph (SEM) shows that the produced polyethylene has highly porous fabric which consists of nanofiber and spherical beads of micron dimension.
研究领域:
高分子化学
·
催化化学
·
材料科学
·
纳米材料
·
聚合物科学
·
石油化工
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Zhanwei Yang,Jin Wang,Hualei Chen,Hecheng Meng,Xiaobing Guo,Shujuan Yu
Two low-methoxy pectins (LMPs) were obtained by local electrochemical pH modification using an H-type double-layer water bath sealed electrochemical cell at the voltage of 180 V for 3 h. The weight-average molecular weight (Mw) of citrus peel pectin (CPP) prepared in the anodic part at room temperature (CPP-A 5/RT ) and in the cathodic part at 5 °C (CPP-C 5/RT ) were 346 kDa and 328 kDa, respectively, and the degrees of methylation (DM) were 36.8 % and 11.9 %. Moreover, the second-order kinetic model was most appropriate for the degradation processes, as free radicals were generated in the anodic part and β -elimination occurred in the cathodic part. Subsequently, CPP-A 5/RT and CPP-C 5/RT were utilized to fabricate food packaging film blending with polyvinyl alcohol (PVA), bcZnO (ZnO coupled with bentonite and colophony) nanorods , and Ca 2+ ions by casting method. Then the prepared films were studied for their ability to maintain the freshness of strawberries. The addition of Ca 2+ ions and bcZnO nanorods increased the thickness, water contact angle (WCA), and mechanical properties of the composite films, while decreased water vapor permeability (WVP). Therefore, the CPP-based films, supplemented with bcZnO nanorods and crosslinked with Ca 2+ ions by “egg-box” model, can serve as an antibacterial food packaging material for food preservation.
研究领域:
食品科学
·
高分子材料
·
食品包装
·
电化学改性
·
纳米复合材料
·
农产品保鲜
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Yuhua Dong,Jianbin Zheng
The work presented that by regulating the proportion between cobalt and 2-methylimidazole in distilled water, a series of Co-based imidazolate framework compounds with diverse shapes were synthesized at ambient temperature. The morphology and structural characteristics of the compounds were surveyed by scanning electron microscope, energy disperse spectra, powder X-ray diffraction and N 2 absorption-desorption. It was found by cyclic voltammetry that the zeolitic imidazolate framework compound synthesized at a ratio of 1:20 had the best electrocatalytic activity to H 2 O 2 reduction, therefore, the compound was chosen to fabricate a H 2 O 2 electrochemical sensor. Electrochemical studies indicated that the sensor had a determination limit of 0.7 μM and short response time within 3 s. The catalytic current was linear with H 2 O 2 concentration from 2.5 to 212.5, 212.5 to 1662.5 and 1662.5 to 6662.5 μM and the sensitivity were 12.2, 5.3 and 2.4 μA mM −1 cm −2 , respectively. Furthermore, the proposed sensor showed a good anti-interference capacity, repeatability and stability.
研究领域:
分析化学
·
材料科学
·
电化学
·
生物传感器
·
纳米材料
·
环境监测
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2015
·
IF 3.368
Xiang Shen,Bing Yan
A series of luminescent Ln 3+ @bio-MOF-1 (Ln = Eu, Tb, bio-MOF-1 = Zn 8 (ad) 4 (BPDC) 6 O⋅2Me 2 NH 2 (ad = adeninate, BPDC = biphenyldicarboxylate)) are synthesized via postsynthetic cation exchange by encapsulating lanthanide ions into an anionic metal–organic framework (MOF), and their photophysical properties are studied. After loading 2-thenoyltrifluroacetone (TTA) as sensitized ligand by a gas diffusion (“ship-in-bottle”) method, it is found that the luminescent intensity of Eu 3+ is enhanced. Especially, when loading two different lanthanide cations into bio-MOF-1, the luminescent color can be tuned to close white (light pink) light output. Additionally, bio-MOF-1 and Eu 3+ @bio-MOF-1 are selected as representative samples for sensing metal ions . When bio-MOF-1 is immersed in the aqueous solutions of different metal ions , it shows highly sensitive sensing for Fe 3+ as well as Eu 3+ @bio-MOF-1 immersed in the DMF solutions of different metal ion. The results are benefit for the further application of functionalized bio-MOFs in practical fields.
研究领域:
无机化学
·
材料科学
·
分析化学
·
纳米生物技术
·
光物理学
·
配位化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2013
·
IF 4.093
Qiang Xu,Yang Yang,Jie Yang,Xiaozu Wang,Zhaohui Wang,Yong Wang
Conformal and smooth TiO 2 thin layers were coated on the surface of porous PTFE membranes subjected to a plasma activation process by atomic layer deposition (ALD). In contrast, TiO 2 was deposited on the PTFE surface as globular particulates without plasma activation due to the inert chemical nature of PTFE surface. X-ray photoelectron spectrometry confirmed the formation of functional groups on the plasma-activated PTFE surface which served as active sites for the homogeneous adsorption and reaction of ALD precursors. Scanning and transmission electron microscopy revealed the uniformity of the deposited layer and the precise control of its thickness by changing ALD cycle numbers. The water contact angle measurement showed that the hydrophobic surface gradually turned to be near superhydrophilic with the increment of ALD numbers. Also, the membrane mean pore size was progressively reduced by simply altering the ALD numbers. At proper deposition conditions , the modified membranes gained an increase of pure water flux of more than 150% and simultaneously a doubled retention compared to the original unmodified membrane. This research provides an efficient approach devoid of any harsh treatments to modifying PTFE membranes for achieving specific functions, which also can be applied to other organic materials especially with chemical inert surface.
研究领域:
材料科学
·
膜科学与技术
·
表面工程
·
高分子化学
·
环境工程
·
纳米科技
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·Vol. 10
·期 6
·108837
·
IF 7.968
Yumei Jian,Ye Meng,Jie Li,Hongguo Wu,Shunmugavel Saravanamurugan,Hu Li
Photocatalytic reductive conversion of bio-derivatives to biofuels and fine chemicals is an eco-friendly and energy-saving way for biomass valorization. Herein, we developed a new and high-performance protocol for control of activity/selectivity in photocatalytic reductive upgrading of biomass to biofuels at room temperature via engineering oxygen vacancy (Ov) and manipulating the exposed crystal surfaces of the TiO 2 -based catalysts, such as efficient cascade photocatalytic hydrogenation-cyclization of ethyl levulinate to γ-valerolactone in water (up to 96% yield, TOF: 112.1 h −1 ), and the selective conversion of 5-methylfurfural to 5-methylfurfuryl alcohol (90% yield) or long carbon-chain coupling products (86% yield) in methanol, respectively. The {101} crystal plane is prone to produce more Ov in situ than the {001} and {110} crystal planes. The formation of Ov was not only beneficial to the adsorption and activation of the bio-based carbonyls, but also could enhance the migration efficiency of the photo-generated carriers and effectively adjust the semiconductor band structure of the TiO 2 -based photocatalyst to promote the visible-light absorption, thus enhancing the overall reductive conversion process, as elucidated by DFT calculations. Also, the charge distribution and adsorption intensity of different exposed crystal surfaces of the photocatalyst were able to control the selectivity of the bioproducts . In addition, the optimal Ov-TiO 2− x {101} catalyst had excellent reusability and could be reused at least five times with no obvious decrease in photocatalytic performance. The strategy of selectivity control via engineering the catalyst exposed crystal surfaces and loaded Ov provides an opportunity for multi-catalytic biomass conversion to biofuels.
研究领域:
催化化学
·
材料科学
·
能源化学
·
环境科学
·
绿色化学
·
表面科学
·
光催化
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2013
·Vol. 15
·期 32
·6368-6373
·
IF 3.879
Shuling Xu,Lei Wang,Haibo Li,Qiaoli Yue,Rui Li,Jifeng Liu,Xiaohong Gu,Shuqiu Zhang
Novel three-dimensional Ag nanoflowers (3DAN) were successfully synthesized through a facile Cu2+ mediated solution method using N,N-dimethylformamide (DMF), which serves as both a reducing agent and a solvent at room temperature. It was found that the introduction of a trace amount of Cu2+ could greatly slow the rate of the Ag+ reaction and thus this process effectively reduced the growth speed of Ag nanoparticles allowing 3DAN to be formed. The mechanism underlying the self-assembly process and shape evolution of 3DAN were systematically investigated by varying reaction time. X-Ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were used to characterize the structure and morphology of the obtained products. X-Ray photoelectron spectroscopy (XPS) was used to assess the chemical state and surface composition of the 3DAN. UV-vis absorption spectra of the products collected from the reaction solution at various stages were taken to study their optical properties. In the measurement of surface-enhanced Raman scattering using rhodamine 6G (R6G) as the probe, the 3DAN exhibited a significant enhancement factor, indicating their potential applications in biosensing and nanodevices.
研究领域:
纳米医学
·
生物传感
·
材料科学
·
胶体化学
·
分子影像学
✓ 已验证
DOI
高影响因子
Laser & Photonics Reviews
·
2023
·Vol. 17
·期 12
·2300476
·
IF 11
Wenhai Sun,Xiang Zhang,Hulin Zhang,Zichen Ren,Mingjun Chen,Yingjun Xiao,Zitong Li,Jianbo Deng,Dukang Yan,Leipeng Zhang,Yao Li
The development of electrochromic devices (ECDs) that can dynamically modulate infrared (IR) emissivity while maintaining a wide color gamut distribution for visible (VIS)-IR compatible spectral manipulation has been a long-standing challenge. Current ECDs are limited by simultaneous changes in IR emissivity and VIS colors when subjected to external potential, restricting their potential applications. This work presents, for the first time, VIS–IR compatible ECDs capable of displaying VIS multicolor and dynamically modulating IR emissivity via a Ge/HfO 2 Fabry–Perot cavity structure. The all-solid-state VIS-IR compatible ECD with the structure of ITO/NiO/Ta 2 O 5 /Li/WO 3 /ITO/Ge/HfO 2 achieves not only emissivity modulation of 0.20 at potentials of −2.5 V and +2.5 V in the wavelength range of 2.5–25 µm, but also, due to the presence of Fabry–Perot cavity, the novelty compatible device structure achieves static multicolor modulation, thus decoupling VIS and IR emissivity modulation. Additionally, a flexible VIS-IR compatible ECD based on polyaniline is also constructed. This novel approach offers a promising possibility for multispectral compatible manipulation, VIS multicolor, and IR signal processing applications.
研究领域:
材料科学
·
光学工程
·
纳米光子学
·
功能材料
·
智能器件
·
表面物理
·
能源材料
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2015
·Vol. 132
·期 20
·
IF 1.768
Yaobin Liu,Zhiqiang Fan
Two tribromide compounds, 1,3-(propanoic acid, 2-bromo-)-2-(2-bromo-1-oxopropylamino)propyl ester (A 1 ) and trimethylolpropane tris(2-bromopropionate) (A 2 ), were synthesized. By Cu/ N,N,N′,N′,N″ -pentamethyldiethylenetriamine (PMDETA)-mediated radical addition-coupling polymerization (RACP) of 2-methyl-2-nitrosopropane (MNP) with the tribromide compounds, two types of hyperbranched polymers were synthesized under mild conditions, respectively. Polymerization degrees of the polymers increased with time gradually, which is in line with a step-growth polymerization mechanism. By tracing the polymerization process by gel permeation chromatography and NMR analysis, proper reaction conditions to get hyperbranched polymers was obtained. Based on the results of NMR analysis on the polymer chain structure, mechanism of forming hyperbranched polymer has been proposed, which includes formation of carbon radicals from the tribromo monomer through single electron transfer, their reaction with MNP to form nitroxide radicals, and cross-coupling reaction of the nitroxide radicals with other carbon radicals. The gelation point of the A 2 -MNP system is larger than that of the A 1 -MNP system, indicating that probability of intramolecular cyclization in A 2 -MNP RACP system is higher than the A 1 -MNP system. The reactivity of —NHCOCH(CH 3 )Br group of A 1 is lower than its two —OCOCH(CH 3 )Br groups, and this resulted in longer distance between two adjacent branch points in the hyperbranched polymer of A 1 -MNP than the A 2 -MNP system. It is possible to adjust the chain structure of RACP-based hyperbranched polymer by changing the reactivity of the functional groups in A 3 monomer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41972.
研究领域:
高分子化学
·
聚合物合成
·
功能高分子
·
材料化学
·
有机合成方法学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 21
·17029-17035
·
IF 3.289
Xiaoyu Zhang,Yu Zhang,Hua Wu,Long Yan,Zhenguang Wang,Jun Zhao,William W. Yu,Andrey L. Rogach
We explore two strategies to improve the performance of hybrid solar cells fabricated using poly(3-hexylthiophene) (P3HT) and colloidal PbSe nanocrystals, which have reached a 1 sun power conversion efficiency of 2.9%. Using an atomic passivation strategy towards inorganic ligand-capped nanocrystals, the electron mobilities of PbSe quantum dot films are improved from 1.95 × 10−6 cm2 V−1 s−1 to 1.15 × 10−5 cm2 V−1 s−1. Employing ultrasmall PbSe nanocrystals allows us to adjust their bandgaps towards the type II heterojunction with P3HT, thus achieving efficient charge separation and transfer between the polymer/inorganic constituents. The device performance dropped to half after 10 days' storage, and the P3HT/PbSe interface was found to play a primary role in this efficiency degradation.
研究领域:
材料科学
·
纳米科技
·
光伏技术
·
半导体物理
·
表面与界面化学
✓ 已验证
DOI
高影响因子
Journal of Nanomaterials
·
2018
·Vol. 2018
·期 1
·1465760
·
IF 2.207
Jiamao Li,Jingwei Hou,Yu Gong,Chengjian Xiao,Lei Yue,Linjie Zhao,Huan Ma,Heyi Wang,Shuming Peng,Chao Chen,Hongli Chen
A liquid-phase reducing method of synthesizing Pt nanocrystals was demonstrated, and dendrite-, cube-, and cuboctahedron-shaped Pt nanocrystals (NCs) with well-defined monomorphic were successfully synthesized through iodine ions mediated with the CTAB agent. When the KI concentration was increased to thirty times of K 2 PtCl 4 at the nucleation stage, the high-quality Pt nanodendrites could be obtained. However, no matter how many KI were added at the growth age, only cube- and cuboctahedron-shaped Pt nanocrystals formed. The results of high-resolution TEM, EDX, and XRD indicated that the size and shape of Pt NCs could be turned by changing the concentration and time of KI. In the nucleation stage, it might be due to that some iodine ions adsorb on the surfaces of Pt NCs, which probably cause the rapid growth process resulting in the formation of Pt nanodendrites. In the growth stage, although high concentrations of I − ions could contribute to the shape control and generate bigger particles of Pt NCs, small Pt particles do not grow into dendrites. The insight into the role of I − ions in synthesis of Pt NCs reported here provided a viewpoint for clearly understanding the formation mechanism of anisotropic platinum nanostructures.
研究领域:
纳米材料科学
·
物理化学
·
无机合成
·
催化化学
·
材料表征技术
✓ 已验证
DOI
高影响因子
Small
·
2024
·Vol. 21
·期 4
·2410657
·
IF 13
Jia Wang,De Wang,Zelin Zhao,Ganggang Chang,Wei Guo,Jun Xu,Yinyu Xiang,Junrui Li,Junsheng Li
Developing cost-effective ruthenium (Ru)-based HER electrocatalysts as alternatives to commercial Pt/C is crucial for the advancement of proton exchange membrane water electrolysis (PEMWE). However, the strong hydrogen adsorption of Ru-based catalysts restricts its activity. Herein, a strategy is reported to tune the electronic structure and improve mass transfer by implanting Ru atoms onto the (002) facet of two-dimensional zeolitic imidazolate framework-67 (Ru@ L ZIF (002) ) to optimize the d -band center ( ε d ) of Ru and the hydrogen spillover behavior. Benefiting from the ultrathin nanosheet structure and optimized ε d of Ru, the over-strong H adsorption energy is weakened and the electron/mass transfer is facilitated. Ru@ L ZIF (002) exhibits an overpotential of 9.2 mV at 10 mA cm −2 and a long-lasting stability of 35 days at 100 mA cm −2 . The mass activity and price activity of Ru@ L ZIF (002) is 2.9 and 14.7 times higher than Pt/C, respectively. More impressively, Ru@ L ZIF (002) delivers a cell voltage of 2.01 V at a high current density of 4 A cm −2 in PEMWE. The excellent long-term durability of 1200 hours operating at 4 A cm −2 with an ultralow decay rate of 7.5 × 10 −3 mV h −1 has been achieved, making it promising as a cost-effective alternative to Pt/C catalyst for PEMWE applications.
研究领域:
电催化
·
材料科学
·
能源化学
·
纳米材料
·
电化学工程
·
可持续能源技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）