COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2014
·
IF 2.354
Ni Cheng,Xiaoyuan Ma,Xiang Sheng,Tao Wang,Rui Wang,Jingjing Jiao,Li Yu
Two structurally similar imidazolium-based anionic surface active ionic liquids (SAILs) with double hydrocarbon chains, viz. 1-butyl-3-methylimidazolium bis(2-ethylhexyl) sulfosuccinate (C 4 mim-AOT) and 1-butyl-3-methylimidazolium bis(2-ethylhexyl) phosphate (C 4 mim-DEHP), were synthesized by a straightforward ion-exchange technique. A comparative investigation of their aggregation behavior with the corresponding traditional anionic surfactants, sodium bis(2-ethylhexyl) sulfosuccinate (Na-AOT) and sodium bis(2-ethylhexyl) phosphate (Na-DEHP) in aqueous solution was performed in detail by surface tension, electric conductivity, fluorescence spectra and dynamic light scattering measurements. The critical micelle concentration (CMC) values for the surfactants with double hydrocarbon chains obtained by different techniques are in good agreement. The surface activity of C 4 mim-AOT and C 4 mim-DEHP is superior to that of the corresponding traditional anionic surfactants, Na-AOT and Na-DEHP. It is also found that for anionic SAILs the nature of the anionic active group is a dominant factor in the determination of their aggregation behavior in aqueous solution, e.g. CMC and aggregation number, while the introduced organic cation plays a minor role. Theoretical calculations show that more conformations and electronegativity for DEHP anion leads to higher aggregation number and CMC values for C 4 mim-DEHP. This work is expected to be of practical values for the environmental friendly anion SAILs in nanomaterial synthesis and phase separation, etc.
研究领域:
物理化学
·
胶体与界面化学
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纳米材料合成
·
环境友好材料
·
分子自组装
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2019
·
IF 3.131
Yanqi Gu,Shayu Li,Yuehong Xu,Jiaguang Han,Miao Gu,Zhipeng Cai,Yan lv,Guoxin Xie,Tianbao Ma,Jianbin Luo
The influence of an external magnetic field on the picosecond network dynamics of the salt (KCl) solution is investigated by terahertz time-domain spectroscopy. Because hydration changes the motions of water molecules clusters, we test hydration by measuring the change of dielectric loss caused by the slow relaxation of water molecules clusters. We find experimentally that the magnetic field enhances the number of water molecules involved in hydration and the radius of dynamic hydration layer in salt solutions. However, with the increasing concentration, there is a downward in the hydration enhancement per equivalent. Meanwhile, the simulated results show the number of water molecules in hydration layers increases which is consistent with our experimental results. Besides, the simulation reveals that external magnetic field mainly affects the second hydration layer and the stability of water molecules network in hydration layer is enhanced with external magnetic field .
研究领域:
物理化学
·
生物物理
·
分子生物学
·
光谱学
·
溶液化学
✓ 已验证
DOI
高影响因子
FUEL
·
2017
·
IF 4.601
Junliang Wang,Shuyan Zhou,Ke Bei,I-Ming Chou,Chunmian Lin,Zhiyan Pan
This work developed a new method for measuring the volume expansion of a CO 2 + n -dodecane mixture, using a fused silica capillary cell (FSCC), combined with a heating-cooling stage and a confocal Raman spectrometer. The cell was constructed on the micron scale to reduce the temperature gradient and reagent consumption. The results confirmed the feasibility of this method that using Raman spectra to verify phase equilibrium, a digital camera to record images of the CO 2 + n -dodecane mixture and a micrometer to measure the volume, a section of water (water seal) between n -dodecane and gas phase to prevent n -dodecane from evaporating. It was shown that the volume expansion factor of the mixture increased with pressure going from 1.0 to 10.0 MPa, but decreased as the temperature was raised from 30 to 80 °C. In addition, a positive quadratic relationship ( R 2 > 0.99) was obtained between Raman peak intensity ratio and volume expansion factor, such that more volume expansion factors could be obtained according to the equations with measured Raman peak intensity ratio data. This experiment widens the ranges of temperature and pressure in the measurements of the volume expansion, and provides more volume expansion data for CO 2 -enhanced oil recovery.
研究领域:
物理化学
·
能源科学
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油气开采
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光谱分析
·
热力学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 108
·89290-89298
·
IF 3.84
Lili Wang,Byung Kee Moon,Sung Heum Park,Jung Hwan Kim,Jinsheng Shi,Kwang Ho Kim,Jung Hyun Jeong
A novel Sm3+-doped Sr2CaWO6 (SCWO) red phosphor, synthesized though a solid-state reaction, was reported. Its crystal structure was analyzed and refined via the Rietveld full-pattern fitting method based on XRD patterns. The CASTEP module of Materials Studio was used to investigate the band structure and density of states of the SCWO. The optical band gap was calculated through the UV-vis diffuse reflectance spectrum and compared with the value predicted by the DFT method. Raman spectra were recorded to confirm the substitution of cations by Sm3+ ions. The broad W–O charge transfer band and narrow excitation band at 406 nm from Sm3+ ions have comparable intensities in SCWO:Sm3+. After the introduction of charge compensators Li+, Na+ or K+, the intensity of the near-UV excitation band at 406 nm was almost twice as much as before. The profiles of the emission spectra under excitation into the charge transfer absorption and f–f transition of Sm3+ are different, and low-symmetry Sm3+ centres are preferentially excited via f–f absorption transitions. The intensity ratios of electronic, magnetic dipole-allowed transitions under different radiations show that the charge compensators can influence the chemical environment around Sm3+.
研究领域:
材料科学
·
固体化学
·
发光材料
·
晶体学
·
电子结构理论
·
无机功能材料
✓ 已验证
DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2014
·
IF 1.716
J. Yuan,W.C. Wang,D.D. Chen,M.Y. Peng,Q.Y. Zhang,Z.H. Jiang
Enhanced 1.8 μm emission from Tm 3+ by Yb 3+ sensitization and bubbling in tungsten tellurite glasses has been demonstrated under the excitation of a 976 nm laser diode . Radiative properties such as spontaneous emission probabilities, radiative lifetimes and fluorescence branching ratios along with absorption and emission cross sections have been calculated from the absorption spectra . The influences of Yb 3+ concentration, Tm 3+ concentration, and bubbling time on spectroscopic properties have been thoroughly investigated. It is found that with increasing the bubbling time to 35 min, OH − content deceases sharply while 1.8 μm emission intensity improves greatly and 3 F 4 level lifetime prolongs to 1.57 ms close to radiative time. After 35 min, they change very little due to almost reaching the dynamic balance. The strength of interaction between Tm 3+ and OH − is determined. The energy transfer mechanism between Yb 3+ and Tm 3+ is proposed by photoemission spectroscopy and lifetime measurement. The energy transfer coefficients have been analyzed by the extended spectral overlap method and hopping model. Large ratio of the forward energy transfer from Yb 3+ to Tm 3+ to the backward one (223) and high energy transfer efficiency (97%) from Yb 3+ to Tm 3+ ensure efficient 1.8 μm emission. Hence, Yb 3+ sensitization and the reduction of OH − content could be expected to open up a possibility to achieve high efficient 2.0 μm lasing from Tm 3+ under a 976 nm LD pump.
研究领域:
光学材料
·
激光物理
·
固体激光器
·
光谱学
·
无机非金属材料
·
光子学
·
稀土发光材料
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2022
·
IF 3.428
Baoqin Mu,Bin Li,Bin Qi
Lanthanide metal–organic framework Ln-MOFs(Ln = Sm, Dy, Dy/Sm) were synthesized by hydrothermal method at 100 °C for 12 h using lanthanide metals (Ln = Sm, Dy, Dy/Sm) as metal ion centers and 1,3,5-benzotrioic acid (H 3 BTC) as ligands. The structural characteristics of Ln(BTC)(H 2 O)·(DMF) were characterized by X-ray Diffraction(XRD), Fourier Transform Infrared Spectroscopy(FT-IR) and Thermogravimetric Analysis(TGA). Scanning electron microscopy showed that the samples showed rod-like morphology, and the fluorescence spectra showed 478 nm and 573 nm corresponding to the characteristic transitions of 4 F 9/2 → 6 H 15/2 (blue light) and 4 F 9/2 → 6 H 13/2 (yellow light) of Dy 3+ , respectively, while orange light at 600 nm and red light at 646 nm corresponded to the characteristic transitions of 4 G 5/2 → 6 H 7/2 and 4 G 5/2 → 6 H 9/2 of Sm 3+ , demonstrating that the double-doped lanthanide metal ions MOF were successfully synthesized. H 7 (P(Mo 2 O 7 ) 6 )/(Dy/Sm-MOF) was used as a sensor for the determination of H 2 PO 4 − , the results of performance evaluation showed that the electrochemical sensor showed a linear relationship between 0.01 and 0.17 mM for H 2 PO 4 − , with a detection limit of 0.005 mM/L, good stability and reproducibility, which opened up a new way for the detection of orthophosphate dihydrogen.
研究领域:
分析化学
·
材料科学
·
电化学
·
无机化学
·
传感器技术
✓ 已验证
DOI
高影响因子
CARBON
·
2013
·
IF 5.868
Xiuqing Meng,Sefaattin Tongay,Jun Kang,Zhanghui Chen,Fengmin Wu,Shu-Shen Li,Jian-Bai Xia,Jingbo Li,Junqiao Wu
ZnMg and NbCl 5 were intercalated in graphite and the presence of such molecules between the graphene sheets results in n- and p-type doping, respectively. The doping effect is confirmed by Hall and Raman measurements and the intercalation process is monitored by scanning tunneling microscopy . After intercalation the carrier concentration increase almost an order of magnitude and reaches values as high as 10 19 and 10 18 cm −3 for p- and n-type doping, respectively. For higher intercalation times, the intercalated graphite turns back to be as ordered as pristine one as evidenced by the reduction in the D peak in Raman measurements. Intercalation compounds show remarkable stability allowing us to permanently tune the physical properties of few-layer graphite. Our study has provided a new route to produce stable and functional graphite intercalation compounds and the results can be applied to other graphitic structures such as few-layer graphene on SiC.
研究领域:
凝聚态物理
·
材料科学
·
纳米科技
·
表面科学
·
半导体物理
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2016
·Vol. 27
·期 7
·7265-7273
·
IF 1.798
Zhang Dongjiu,Cheng Haifeng,Zhang Zhaoyang,Kang Yue
This paper introduced a general method of etching suspended graphene by nonmetallic SiO x nanoparticles (SiO x NPs) in graphene synthesis. Effects of etching time, concentration of silica gel and type of graphene on the etching mode of graphene have been systematically considered with using as-grown graphene film on a silica gel coating copper as model system. Nonmetallic SiO x NPs acted as etchant plays important role in the in situ etching process during the fabrication of graphene. The etched multilayer graphene pattern can be modulated from large area films to a rectangle pattern by varying the Si concentration and etching time, while single layer graphene pattern alters little. The morphology and critical structure of SiO x etched graphene were characterized by Raman spectra, transmission electron microscopy, scanning electron microscope and X-ray photoelectron spectrum. The process and mechanism described here open the way for tailoring graphene via nanoparticles instead of metal, which show significant influence of the electrical properties of graphene.
研究领域:
纳米材料学
·
表面科学
·
凝聚态物理
·
材料化学
·
电子显微学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Ming Li,Xiaoqin Yuan,Haoran Ruan,Xiandong Wang,Yongping Liu,Zhenhuan Lu,Jiefeng Hai
A new method for synthesizing freestanding PbS-CH 3 NH 3 PbI 3 (MAPI) core-shell nanoparticles (NPs) with enhanced light absorption and photoelectric properties was reported. The transmission electron microscopy (TEM) and energy dispersive spectrometer (EDS) analysis confirmed the core-shell structure of the obtained sample. The Vis-NIR spectra proved the core-shell sample absorbed light both in visible and near infrared region . For comparison, oleic acid/oleylamine molecule capping PbS NPs, MAPI molecule capping PbS NPs, and PbS-MAPI core-shell NPs were used to fabricate Schottky solar cells. PbS-MAPI core-shell NPs based solar cells delivered a photocurrent response from both the PbS and MAPI, and achieved the highest overall PCE.
研究领域:
材料科学
·
纳米科技
·
光电子学
·
能源材料
·
半导体物理
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2018
·
IF 6.759
Xiaolong Liu,Qingzhen Han,Wenbo Shi,Cheng Zhang,Erwei Li,Tingyu Zhu
In this work, ruthenium-based bimetallic catalysts of 1Ru-5 M/TiO 2 (M = Co, Ce, Fe, Mn, Cu, Ni) were prepared and evaluated in ethyl acetate oxidation. It was found that 1Ru-5Cu/TiO 2 gave the highest catalytic activity. The influence of CuO content and the preparation method on the catalytic activity was also studied. 1Ru-5Cu/TiO 2 showed great catalytic stability in the on-stream reaction test. The influence of H 2 O on the catalytic activity is presented. The bimetallic catalyst 1Ru-5Cu/TiO 2 showed better catalytic performance than the monometallic catalysts 1Ru/TiO 2 and 5Cu/TiO 2 . XRD, TEM, HAADF-STEM, H 2 -TPR, and XPS characterizations were conducted, and the synergistic effect between Ru and Cu was well presented. In situ FTIR studies were also conducted, and the reaction intermediates were revealed on the catalyst surface. The theoretical calculations suggested that ethyl acetate is more easily adsorbed on the CuO surface, while it reacts more easily on the RuO 2 surface . Accordingly, a reaction mechanism for the catalytic oxidation of ethyl acetate over a Ru-Cu bimetallic catalyst is proposed.
研究领域:
催化化学
·
环境化学
·
表面科学
·
材料化学
·
物理化学
✓ 已验证
DOI
高影响因子
Nanoscale
·
2019
·Vol. 11
·期 36
·16907-16918
·
IF 6.97
Hong Lin,Jian Mao,Minchao Qin,Zhilong Song,Wanjian Yin,Xinhui Lu,Wallace C. H. Choy
While red is one of the primary colors for display applications, the investigation of visible red emitting perovskites, particularly 2D perovskites, is relatively limited. In this work, we demonstrate a single-phase Ruddlesden–Popper quasi-2D (C3H7NH3)2CsPb2I7 perovskite for red color LEDs. Through increasing the annealing temperature of (C3H7NH3)2CsPb2I7 perovskite thin films, we have successfully achieved tunable emission wavelengths from 654 to 691 nm. Equally important, for all the quasi-2D perovskite LEDs, once the annealing temperature is fixed, the emission spectrum is independent of bias voltages, which is very important for their use in lighting and displays. With the analysis of the crystallinity, morphology, and thermodynamic stability of the quasi-2D perovskite, we find that the obtained (C3H7NH3)2CsPb2I7 perovskite is a single-phase quasi-2D perovskite with only n = 2 phase. Besides, we found that the red shifting of emission wavelength is caused by the increase of perovskite crystal size while increasing the annealing temperature. Our results also show that the temperature-induced color tunability can be applied to a series of quasi-2D perovskites with different alkylammonium cations. Importantly, we find that short alkylammonium spacers offer better electrical properties for efficient current transport and high performance in LED applications. This work contributes to controlling the optoelectronic properties of quasi-2D perovskites via controlling their crystal growth as well as paves the way to realize practical lighting and display applications of perovskite LEDs.
研究领域:
材料科学
·
光电功能材料
·
半导体器件
·
纳米结构材料
·
固态照明
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 30
·期 2
·1699-1705
·
IF 2.324
Teng Fei,Chen Dong,Ma Yuzhe,Ji Shaohua,Liu Jiaojiao,Wang Tianhua,Tang Jie,Cao Lifeng,Teng Bing
N,N -dimethylamino-4′-N′-methylstilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS)-graphene ex-situ and in-situ composite films with 2% concentration of graphene were first prepared and systematically investigated. The crystallinity of DSTMS-based composite films were confirmed by XRD analysis, and the functional groups of composite films can be obtained by FT-IR. Optical absorptions were recorded using UV–Vis-NIR spectral analysis, and the band gap and extinction coefficient of the films were calculated. The thermal stability of the composite films were analyzed by TG/DSC. The pressure sensitive resistance test showed that the pressure sensitive signal of the composite films were significantly increased after graphene added, while the signal of DSTMS film eventually disappears. This work expands the application of organic nonlinear crystal DSTMS in optics and electricity by doping graphene.
研究领域:
材料科学
·
凝聚态物理
·
功能材料
·
非线性光学
·
纳米复合材料
·
电学性能
·
光学性能
·
热分析
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）