JOURNAL OF CHEMICAL THERMODYNAMICS
·
2016
·
IF 2.196
Peizhu Zheng,Dongxing Cai,Jihua Zhao,Weiguo Shen
The mixed surfactants of dodecyltrimethylammonium bromide (DTAB) and 1-dodecyl-3-methylimidazolium bromide (C 12 mimBr) in aqueous solutions were studied by measurement of electrical conductivity and isothermal titration microcalorimetry (ITC). The critical micelle concentrations (cmc) and the degree of dissociations of counter ions were determined for this system at various surfactant compositions, and the thermodynamic properties of micellization were evaluated. A one-parameter Margules equation was used to fit the cmc values to calculate the mole fraction, the activity coefficients of two surfactant components and the excess properties in mixed micelles.
研究领域:
胶体化学
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物理化学
·
表面化学
·
热力学
·
溶液化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2019
·
IF 4.561
Xiao-Qian Wei,Wan-Ju Zhang,Lu Lai,Ping Mei,Li-Mei Wu,Yan-Qun Wang
The effects of cationic surfactants on the properties of Pickering emulsions stabilized by silica nanoparticles (nano-SiO 2 ) were investigated. The zeta potential , three-phase contact angle ( θ ), and dynamic interfacial tension (DIT) were measured to analyze the interaction between hydrophilic nano-SiO 2 and four different cationic surfactants (i.e., dodecyltrimethylammonium bromide [DTAB], bis-quaternary ammonium salts [BQAS-12], multiple quaternary ammonium salts [MQAS-12], and dimethyldioctadecylammonium bromide [DDAB-18]). All these surfactants can naturally improve the stability of Pickering emulsions induced by hydrophilic nano-SiO 2 . The nano-SiO 2 /MQAS-12 mixtures exhibited the best ability to stabilize the O/W emulsions, followed by nano-SiO 2 /BQAS-12 mixtures. The nano-SiO 2 /DDAB-18 mixtures can induce emulsion inversion from O/W to W/O. All emulsions exhibited excellent salt tolerance and acid-base resistance properties. Determining the zeta potential showed that nano-SiO 2 had the highest negative charge at the pH of 9.5. Thus, the surfactant molecules can be adsorbed remarkably on the nano-SiO 2 surface. Modification with different cationic surfactants can significantly increase the θ value of nano-SiO 2 , but the bilayers for DTAB-12, BQAS-12, and MQAS-12, except for DDAB-18, were adsorbed. DIT curves indicated that competitive adsorption of the surfactants occurred between the oil/water interface and nano-SiO 2 surface. The competitive adsorption of MQAS-12 was stronger than those of BQAS-12 and DTAB-12. The nano-SiO 2 /DDAB-18 mixture had an apparent induction region and required a considerable amount of time to reach equilibrium. The modified nano-SiO 2 was also not adsorbed in the oil/water interface spontaneously, which may be due to the large size of particles compared with small surfactant molecules.
研究领域:
胶体与界面化学
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纳米材料科学
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乳液工程
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物理化学
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表面科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·Vol. 47
·期 16
·22776-22785
·
IF 4.527
Kaidan Wu,Yefeng Feng,Jin Ke,Bingwen Yang,Zhiling Guo,Deping Xiong,Miao He
Graphite nanosheets coated by LiF/SnO 2 composites are designed to obtain a lithium ion anode material with excellent performance. LiF nanoparticles play a significant role in improving the electrochemical performance by inhibiting electrolyte decomposition and providing excess Li sources during cycling. The obtained LiF@SnO 2 @C electrode shows an outstanding capacity of 951.9 mAhg −1 at 0.2 Ag -1 after 370 cycles and excellent long cycling performance of 650.0 mAhg −1 at 1.0 Ag -1 after 930 cycles. First-principles calculations demonstrate that F-doped SnO 2 (−2211.8 eV) has a lower free energy compared to SnO 2 (−1937.4 eV), resulting in a robust composite architecture that gives rise to high cycling stability.
研究领域:
材料科学
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电化学
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纳米科技
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能源存储
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计算材料学
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DOI
高影响因子
Analytical Methods
·
2016
·Vol. 8
·期 24
·4926-4933
·
IF 1.915
Dejiang Rao,Qinglin Sheng,Jianbin Zheng
Herein, we report a simple and attractive self-assembly strategy for preparing graphene oxide–multiwalled carbon nanotube–(1-pyrenemethylamine)–gold (GO–MWCNT–PMA–Au) nanocomposites using 1-pyrenemethylamine (PMA) as a coupling agent. The morphology and composition of the nanocomposites were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). Further, a non-enzymatic nitrite sensor was fabricated by immobilizing GO–MWCNT–PMA–Au nanocomposites on a glassy carbon electrode (GCE). To obtain the optimal electrochemical experimental conditions, the effects of pH value and the volume of the as-prepared Au nanoparticle suspension were carefully investigated. Its electrochemical sensing properties were studied by cyclic voltammetry and differential pulse voltammetry. The electrochemical investigation showed that the GO–MWCNT–PMA–Au nanocomposites exhibited good catalytic performance for the oxidation of nitrite. The nitrite electrochemical sensor presented a wide linear range from 2.0 × 10−6 to 1.0 × 10−2 mol L−1, a high sensitivity of 483.51 μA mM−1 cm−2 and a low detection limit of 0.67 μmol L−1 at a signal-to-noise ratio of 3 (S/N = 3). It also exhibited good anti-interference capability and stability. This paper provides a self-assembly strategy for preparing nanocomposites which are used to construct improved electrochemical sensors.
研究领域:
分析化学
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纳米生物技术
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电化学传感
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环境监测
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食品安全
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2020
·
IF 5.778
Kexin Chen,Xi Wang,Pengfei Xia,Jinxin Xie,Jing Wang,Xukai Li,Yiming Tang,Laisheng Li
Z-scheme Cu 2 O-(rGO-TiO 2 ) photocatalyst was successfully synthesized via a simple three-step approach for 2,2′,4,4′-tretrabromodiphenyl ether (BDE47) reductive removal under simulated solar irradiation. Unlike the traditional heterojunction , the addition of reduced graphene oxide (rGO) enhanced the redox ability of Cu 2 O-TiO 2 by increasing charge transfer. When modifying Cu 2 O films by adding 1% rGO and coating with 70% TiO 2 , the resulting Cu 2 O-(rGO-TiO 2 ) exhibited the best photocatalytic activity for BDE47 removal. The charge transfers of Cu 2 O-(rGO-TiO 2 ) were proven to follow a Z-scheme pathway through the electron paramagnetic resonance analysis. The degradation pathways of BDE47 were elucidated by identifying intermediate products via gas chromatography-mass spectrometry (GC-MS) and gas chromatography (GC). Photo-electrons (e − ) generated from the conduction band of Cu 2 O and hydrogen protons (H 0 ) reduced from H + in water were the main contributing elements for the removal of BDE47, which response to the ortho and para debromination . Ortho-Br of BDE47 was attacked by e − and BDE28 was the dominant debromination product on the first stage. Then e − and H 0 attacked ortho-Br and para-Br of BDE28 to form BDE15 and BDE8, respectively. The concentration of BDE8 was higher than that of BDE15, suggesting that H 0 played the most important role on the second debromination stage. An effective Cu 2 O-(rGO-TiO 2 )-based Z-scheme system for BDE47 debromination was proposed in this study, which may contribute to the development of novel green technologies.
研究领域:
环境科学
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光催化化学
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环境污染与控制
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材料科学
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绿色技术
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有机污染物降解
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2016
·
IF 6.333
Fanli Meng,Yi Luo,Yali Zhou,Jinwen Zhang,Yanzhen Zheng,Guozhong Cao,Xia Tao
A plasmon-enhanced upconversion composite Y 2 O 3 :Er/Au@TiO 2 (SYE/A@T) with a three-dimensional starlike morphology is prepared and then mixed with submicron TiO 2 (200 nm) to form a multifunctional scattering layer in TiO 2 -based dye-sensitized solar cells (DSSCs). In such starlike micronsized upconverter, Au nanoparticle-assisted plasmon effect can intensify the upconversion emission of Y 2 O 3 :Er, and simultaneously TiO 2 coating can improve the charge transport within SYE/A@T. Therefore, the SYE/A@T shows extended light-absorbing range to near-infrared region and improved light-scattering ability, leading to an improved photovoltaic performance of DSSCs. With the optimum mixing ratio, a conversion efficiency of 8.62% is attained, which is a significant improvement of 27.6% compared with the cell without adding SYE/A@T. Our work provides a feasible strategy to prepare an upconversion composite with plasmon-enhanced emission and enable this composite to accommodate the DSSCs system and improve the conversion efficiency of DSSCs.
研究领域:
材料科学
·
光伏技术
·
纳米光学
·
能源材料
·
表面等离激元
✓ 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
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光学工程
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纳米光子学
·
功能材料
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智能器件
·
表面物理
·
能源材料
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Zhi-Hao Jin,Jin-Tao Chen,Wang Li,Shu-Bao Song,Jiu-Zhong Yang,Zhen-Yu Tian
Owing to significant advantages over traditional biofuels, 2-methylfuran (MF) has arisen extensive interest as next generation biofuels . Atmospheric pressure pyrolysis of a 1:1 blend of MF with a three-component (3C) surrogate jet fuel was conducted in a flow tube using synchrotronphotoionization and molecular beam mass spectrometry techniques within a temperature range of 898–1223 K. Therein, the 3C surrogate fuel consists of 66.2% n-dodecane (NC 12 H 26 ), 18.0% 1,3,5-trimethylcyclohexane (T135MCH) and 15.8% n-propylbenzene (NPB, A1C 3 H 7 ). The detailed kinetic model including 579 species and 3474 reactions was developed via validating against both measured and literature data with reasonable agreement. MF exhibits no obvious influence on the 3C components pyrolysis . However, 3C mixtures play an important roles in MF decomposition: lower initial temperature and different decomposition pathways. In the meantime, n-propylbenzene (NPB) pyrolysis curve in 3C and 3C+MF significantly transfers to low temperature zone after 1000 K in contrast to pure NPB, while smaller change was found in the decomposition curve of n-dodecane. Compared with 3C pyrolysis, 3C+MF blends have less formation of aromatic species and light hydrocarbons except for vinylacetylene (C 4 H 4 ) and acetylene (C 2 H 2 ). Allyl radical (C 3 H 3 ) has significant roles in benzene ring formation. The combination of allyl radical with propargyl radical producing benzene and H radical (aC 3 H 5 + C 3 H 3 = A1 + 2H) has the highest contribution to the benzene formation in both 3C and 3C+MF. Moreover, most of naphthalene (A2) formation is also related to C 3 H 3 radical via reaction: A1CH 2 + C 3 H 3 = A2 + H, rather than via HACA (hydrogen abstraction carbon addition) reaction. Interaction of fuel blends was mainly presented through the common and important sensitive reactions which are much to do with CH 3 and H radicals. The overview of product distribution was investigated by providing comparisons of carbon conversion rates during the pyrolysis of 3C and 3C+MF. These results will be helpful to better understand the pyrolysis properties of MF/jet fuel surrogate blends and could contribute to developing new generation biofuels for aviation.
研究领域:
燃料化学
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燃烧动力学
·
生物燃料
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能源化学
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反应机理
·
质谱分析
✓ 已验证
DOI
高影响因子
Laser & Photonics Reviews
·
2024
·Vol. 19
·期 1
·2401012
·
IF 9.8
Pengcheng Jian,Maohua Chen,Dongyan Li,Yongming Zhao,Weijie Liu,Yuang Luo,Xiantai Tian,Meng Peng,Xing Zhou,Jiangnan Dai,Feng Wu,Changqing Chen
The extraordinary mechanical compliance of 2D molybdenum disulfide (MoS 2 ) makes it an ideal candidate for strain modulation of various electrical and optical properties. However, developing facile methods for accurate and stable engineering of strain still remains a major challenge. Here, a novel and effective method is demonstrated for introducing periodic strain into monolayer MoS 2 by direct growth on nano-patterned sapphire substrates (NPSS). A mixed aqueous solution of Na 2 MoO 4 and NaOH is spin-coated on the NPSS and sulfurated in one step by chemical vapor deposition (CVD). Highly oriented monolayer MoS 2 single-crystal nanosheets with high quality and few sulfur vacancies are achieved conformally on the NPSS via a liquid-mediated growth mode. Notably, the periodically distributed blue shift of the PL emission peak demonstrated periodic compressive strain is introduced into the nano-patterned MoS 2 via the thermal expansion difference between MoS 2 and substrates. Furthermore, photodetectors fabricated using the nano-patterned monolayer MoS 2 exhibit a high photo-to-dark current ratio (PDCR) over 10 6 , an excellent detectivity of 5.4 × 10 13 Jones, and a fast photoresponse of 7.7 ms, owing to the strain-induced back-to-back built-in electric field, enhanced light absorption by light-scattering effect and fewer S vacancy defects. The scanning imaging demonstration based on the single-pixel nano-patterned MoS 2 photodetector further confirms its great potential in image sensors. This work hereby presents a pathway for direct conformal growth of nano-patterned monolayer MoS 2 with precisely periodic strain, which should inspire the applications for high-performance optoelectronic devices via the strategy of patterned substrate engineering by the periodic nanostructures.
研究领域:
材料科学
·
纳米科技
·
光电子学
·
凝聚态物理
·
表面科学
·
半导体器件
✓ 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
Materials Today Physics
·
2022
·
IF 11.021
Zilin Ruan,Jianchen Lu,Baijin Li,Qizan Chen,Zhenliang Hao,Lei Gao,Jinming Cai
Structural defects in two-dimensional materials offer an effective way to engineer their functionalities. In-situ local measurements to build the structure-function relationship are crucial for future device technology. Here, we present a comprehensive study of intrinsic defects in single-layer WS 2 grown by chemical vapor deposition using a combination of scanning tunneling microscopy/spectroscopy, non-contact atomic force microscopy and density functional theory calculations. We probed the rarely observed positively charged defects and the intersection of adjacent charging rings at sufficiently high bias caused by subsurface defects. We also directly identified and visualized the widely observed negatively charged defects as chalcogen vacancies-related defects. The results reported here will guide future efforts of targeted defect engineering and doping of the single-layer transition metal dichalcogenides .
研究领域:
材料科学
·
凝聚态物理
·
纳米科技
·
表面科学
·
二维材料
·
半导体物理
✓ 已验证
DOI
高影响因子
PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2018
·Vol. 37
·期 1
·565-573
·
IF 5.336
Xiaoyuan Zhang,Yuyang Li,Chuangchuang Cao,Jiabiao Zou,Yan Zhang,Wei Li,Tianyu Li,Jiuzhong Yang,Philippe Dagaut
The kinetics of propanal oxidation was studied in a jet-stirred reactor (JSR) at atmospheric pressure. The investigated temperature range is from 450 to 800 K at two different equivalence ratios (0.35 and 4.0). Thanks to the synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS), critical intermediates were identified, including methylperoxy, methyl hydroperoxide , ethylperoxy, ethyl hydroperoxide, α-lactone, β-propiolactone and ketohydroperoxides. A kinetic model for propanal oxidation was also developed and validated against the present experimental results, as well as those available from the literature. Main chain-branching pathways under the investigated conditions were analyzed based on present experimental data and kinetic model . The O 2 addition reaction to the propanoyl radical and subsequent oxidation reactions play an important role in determining the oxidation rate of propanal under fuel-lean conditions, especially in the low-temperature oxidation region. Under fuel-rich conditions, the decomposition of the propanoyl radical is predominant and C 2 H 5 relevant reactions consequently determine the kinetics of oxidation of propanal.
研究领域:
物理化学
·
燃烧化学
·
反应动力学
·
分析化学
·
能源化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）