ULTRASONICS SONOCHEMISTRY
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2021
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IF 7.491
Hanyang Gao,Kunkun Pei,Dong Lei,Guoxin Hu,Yan Chao,Aihua Meng,Hongcheng Wang,Wei Shentu
Due to the tunability in mass transfer, solvation and solubility, gas-expanded liquids show advantages over traditional organic solvents in many characteristics. Ultrasonication is a commonly used method to promote heat and mass transfer. The introduction of ultrasonic technology into the gas-expanded liquid system can promote the polymerization of polymer monomers, enhance extraction efficiency, and control the growth size of nanocrystals, etc. Although acoustic cavitation has been extensively explored in aqueous solutions, there are still few studies on cavitation in organic liquids, especially in gas-expanded liquid systems. In this article, the development of cavitation bubble cloud structure in CO 2 -expanded N, N-dimethylformamide (DMF) was observed by a high-speed camera, and the cavitation intensity was recorded using a spherical hydrophone. It was found that the magnitude of the transient cavitation energy was not only related to input power, but also closely related to CO 2 content. The combination of ultrasound (causing a rapid alternation of gas solubility) and gas-expanded liquid system (causing a decrease in viscosity and surface tension of liquids) is expected to provide a perfect platform for high-speed mass transfer.
研究领域:
化学工程
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超声技术
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材料科学
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DOI
PubMed
高影响因子
JOURNAL OF MATERIALS RESEARCH
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2014
·Vol. 29
·期 18
·2170-2178
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IF 1.815
Xiaomeng Lü,Jiayu Shen,Ziwei Wu,Jiaxi Wang,Jimin Xie
Plasmonic Ag nanoparticles (AgNPs) with narrow distribution were successfully loaded on graphitic carbon nitride (g-C3N4) sheet by thermal polymerization of melamine precursor and a simple wet-chemical pathway in the presence of polyvinylpyrrolidone (PVP). N,N-dimethylformamide (DMF) was used as an efficient reducing agent as well as a solvent and its presence facilitated homogeneous distribution of AgNPs under mild reaction condition and easy control of its particle growth under different precursor amounts. Ag/g-C3N4 composites of different Ag content were prepared, and the phase, chemical structure, morphologies, electronic and optical properties of Ag/g-C3N4 heterostructures were well characterized, respectively. The photocatalytic activity of Ag/g-C3N4 composites was evaluated by the decolorization of methyl orange (MO), and they exhibited superior photocatalytic activity to bulk g-C3N4 under visible-light irradiation. Influence of Ag content to photocatalytic activity was also discussed and possible mechanism was explored based on the analysis of photoluminescence spectra (PL) and photodecoloration activity.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
RSC Advances
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2015
·Vol. 5
·期 56
·44783-44791
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IF 3.84
Rui Zhang,Baochang Zhang,Shuqing Sun
In this paper, we report on the successful preparation of high-quality graphene sheets with a large-size in N,N-dimethylformamide (DMF) solvent by sonication-free liquid-phase exfoliation (LPE) of graphite assisted with urea as the precursor of the intercalating agent melamine. Through the characterizations of the graphene sheets obtained with transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectroscopy and XPS, these graphene sheets were found to be high-quality, defect-free, single or-few-layer with areas in the range of 100–1000 μm2. The influences of reflux time and the mass ratio of urea to graphite on the graphene concentration (CG) in the resulting dispersions were investigated. The graphene dispersions were fabricated into flexible films that show comparable conductivity. The exfoliation mechanism of graphite in our new sonication-free LPE method is also discussed.
研究领域:
材料科学
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纳米技术
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DOI
高影响因子
Nano Energy
·
2019
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IF 15.548
Jingjing Jiang,Rajiv Giridharagopal,Erin Jedlicka,Kaiwen Sun,Shaotang Yu,Sanping Wu,Yuancai Gong,Weibo Yan,David S. Ginger,Martin A. Green,Xiaojing Hao,Wei Huang,Hao Xin
Theoretical calculation suggests Cu-rich chalcopyrite absorbers contain less defects and have potential to achieve better performance than Cu-poor absorbers. However, this has not been demonstrated due to the detrimental Cu 2-x Se impurity remaining in the absorber. Here, we report highly efficient Cu-rich chalcopyrite solar cells by selenizing dimethylformamide molecular precursor solution processed precursor films under high Ar pressure. Characterizations using XRD , Raman, SEM, TEM , c-AFM, PL, and glow discharge optical emission spectroscopy (GDOES) show high pressure selenization enables high quality Cu-rich chalcopyrite absorber materials with stoichiometric composition, smooth surface, high conductivity, and Cu 2-x Se free grain boundaries, leading to efficient CuIn(S,Se) 2 and Cu(In,Ga)(S,Se) 2 devices with power conversion efficiency of 14.5% and 15.2%, both are the best performing chalcopyrite solar cells from non-hydrazine solutions. Our results demonstrate high Ar pressure selenization is a new strategy to fabricate high quality Cu-rich absorber which has great potential to further improve chalcopyrite solar cell efficiency.
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DOI
高影响因子
CHEMISTRY OF MATERIALS
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2020
·
IF 9.567
Stephen V. Kershaw,Wai Kin Yiu,Aleksandr Sergeev,Andrey L. Rogach
Most successful syntheses of long-wavelength infrared (IR)-absorbing/emitting Hg-chalcogenide quantum dots (QDs) use either aqueous- or organic-solvent-based methods. Accounts of IR QD growth in aprotic solvents such as dimethyl sulfoxide (DMSO) or dimethylformamide (DMF) are much less common, and yet, producing QDs in such solvents can be useful from the perspective of further reactions to conjugate or incorporate the QDs with other materials since such solvents can be a useful meeting ground for both organic and ionic solutes. Here, we start by demonstrating long-wavelength infrared emission (across the wide spectral range of up to 4500 nm) in HgTe QDs grown in DMF under basic conditions. While many existing synthetic approaches use soluble chalcogen precursors in adduct, salt, or organo-chalcogenide forms, we have opted to take the approach of using slow addition of gaseous H2Te generated under programmed control, which allowed us to investigate the growth kinetics to manipulate the different competing processes and to obtain larger HgTe QDs with the best size distributions on a repeatable and controlled basis. We demonstrate how the nucleation process of HgTe QDs can be carried out analogously to the way that it occurs in classic hot injection syntheses but in our case at a far lower (subambient) temperature, owing to the use of a much more labile Te precursor. We also demonstrate the use of a two-stage, seeded QD growth process, which allows the synthesis conditions for the initial nucleation step and the subsequent enlargement stage to be decoupled; in other words, the QD concentration during the enlargement phase need not be forced to be excessively large by the choice of nucleation conditions. This approach should eventually be extendable to making >5000 nm emitting HgTe QD-based materials, and the use of aprotic solvents will offer compatibility with other nanomaterial chemistries, e.g., oxide glass formers, etc., for the synthesis of composites. By comparing the emission spectra of HgTe QDs grown in DMF with the spectra of those grown in DMSO, we show that polaron-mediated coupling to ligands and solvents, previously seen when using DMSO, can be substantially suppressed using our new synthetic method.
研究领域:
材料科学
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化学
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产品关联
DOI
高影响因子
Journal of Materiomics
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2022
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IF 8.589
Xuedi Zhang,Jin Chen,Han Zhang,Pengfei Zhu,Rong Wang,Fu Li,Bo Li
Bi 2 Te 3 -based materials were prepared by direct ink writing (DIW) 3D printing and their microstructure and thermoelectric properties were investigated with an emphasis on the effect of the content of DMF and Te/Se addition. As the mass ratio of DMF in the composition increased from 6.5% to 8.0% (in mass), the electrical conductivity deteriorated because of the corresponding increased porosity and organic remains in the samples. However, the volatilization of DMF would reduce the fluidity of the slurry. Thus, thermoelectric slurry with 7.0% DMF is the most suitable mass ratio for 3D printing. Additionally, adding Te in the p-type Bi 0.4 Sb 1.6 Te 3 and adding Se in the n-type Bi 2 Te 2.6 Se 0.4 have significantly improved their electrical conductivity due to the increased carrier concentration and mobility. Combining with the moderate Seebeck coefficient (∼200 μV/K), high power factors with ∼802 μW·m −1 ·K −2 and 1266 μW·m −1 ·K −2 were obtained for the n-type Bi 2 Te 2.6 Se 0.4 +10%Se and p-type Bi 0.4 Sb 1.6 Te 3 +7%Te, respectively, which result in the final relatively high zT values of 0.68 at 573 K and 0.56 at 330 K for n-type and p-type 3D-printed samples.
研究领域:
材料科学
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热电技术
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DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2018
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IF 5.091
Yuelong Xu,Shasha Wang,Bin Ren,Junping Zhao,Lihui Zhang,Xiaoxi Dong,Zhenfa Liu
Carbon aerogels with excellent conductive characteristics and high specific capacitance have attracted more and more interests for next-generation energy storage applications. Three-dimensional interconnected Mn 2 O 3 /carbon aerogel supercapacitor electrodes are prepared by a novel doping method using MnO 2 coordinated by N, N-dimethylmethanamide (DMF). The coordinative MnO 2 (DMF/MnO 2 ) plays a key role in the sol-gel process of resorcinol and formaldehyde. The doped carbon aerogels exhibits a high specific surface area of 859 m 2 g −1 and a good pore-size distribution of 10–15 nm. All of the doped carbon aerogels exhibit higher specific capacitance than pure carbon aerogels, and the highest specific capacitance (170 F g −1 ), at current density of 1.0 A g −1 , is obtained in Mn–CA–5% when 5 mol% DMF/MnO 2 is added to the precursor solution. The specific capacitance is as high as 100 F g −1 , at current density of 10.0 A g −1 , and 97% of initial capacitance is retained over 1000 cycles at a current density of 5.0 A g −1 . The doped carbon aerogels exhibits a high coulombic efficiency (up to 99.8%) and a good rate capability. The corresponding result is due to the novel doping method of DMF/MnO 2 addition.
研究领域:
材料科学
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能源存储
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DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2021
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IF 10.588
Jiaxin Zhu,Yihua Chen,Yurong Gu,Hang Ma,Mingyue Hu,Xinlei Gao,Tongzhou Liu
The discharge of widely used per- and poly-fluorinated compounds (PFCs) leads to their environmental prevalence, bioaccumulation and biotoxicity; and attracts researches focusing on their treatment in wastewater. Electrochemical reductive treatment is a promising alternative due to its milder reaction conditions and easy operation. The feasibility of electrochemical reductive decomposition of PFOA using a Rh/Ni cathode was explored. The Rh/Ni cathode was fabricated by coating Rh 3+ on Ni foil through electrodeposition . The Rh coating was primarily elemental and in a Rh(111) crystalline form. PFOA decomposition and defluorination were observed when using the Rh/Ni cathode where DMF was the solvent and the cathode potential was −1.25 V. A hydrodefluorination reaction was considered having occurred. Because possessing d electrons and empty d orbitals, the Rh coating enhanced PFOA adsorption onto the cathode surface and facilitated C F bond activation through Rh···F interactions. Moreover, the Rh(111) crystal helped chemisorb the generated H* and supply it participating in PFOA decomposition. With the continuous interaction of cathode-supplied electrons, C F bond would ultimately dissociate and transform to C H bond by H* substitution. Adding FeCp 2 * as a supporting electrolyte enhanced PFOA decomposition by working as the shuttle facilitating PFOA migration to the cathode surface.
研究领域:
环境科学
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电化学
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污染治理
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DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2020
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IF 2.369
Guang Yang,Jianqiang Zhang,Chunjuan Huang,Xin Song,Renjie Xu
Water as an auxiliary solvent is added to various alcohol solvents (methanol, ethanol, and isopropanol) and N,N-dimethylformamide (DMF) to form a variety of liquid mixtures, which are divided into different types according to different proportions. Starting from pure water, 0.1 mass fraction of organic solvents is added at a time until the ratio of organic solvent is 1. The abovementioned liquid mixtures are used as solvents to dissolve halosulfuron-methyl at 278.15–323.15 K under 101.2 kPa by means of the isothermal static technique. The experimental solubility of halosulfuron-methyl was calculated and validated by using three various computational models, i.e., Jouyban–Acree model, modified Apelblat–Jouyban–Acree model, and van’t Hoff–Jouyban–Acree model. Considering that there are many factors that change the experimental results, this experiment mainly selected temperature and water content as two factors as the main independent variables. From the point of view of temperature, it changes from a low value to a high value, so it is obvious that the solute mole fraction also follows its footsteps. Unlike the temperature, as the organic solvent is continuously diluted by water, the solute solubility changes in the opposite direction to the water content. By controlling the variable method to ensure that the above two variables remain unchanged, DMF has the best dispersion ability for all the selected solvents to dissolve halosulfuron-methyl. The solubility maximum of 2.542 × 10–3 at 323.15 K was found in pure DMF, and four systems followed the descending order as (DMF + water) > (ethanol + water) > (methanol + water) > (isopropanol + water). The largest relative average deviation and root-mean-square deviation values were 5.70 × 10–3 and 6.90 × 10–6, respectively. For drugs with poor water solubility and dissolution rate, measuring their solubility and understanding their dissolution properties could effectively help solve the problem of nonwetting and nondiffusion. The obtained equilibrium solubility and correlation parameters of halosulfuron-methyl in studied cosolvency systems could be favorable for the industrial production, recrystallization, and purification processes of API halosulfuron-methyl.
研究领域:
药物化学
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物理化学
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2018
·Vol. 29
·期 21
·18868-18877
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IF 2.324
Zheng Haisong,Li Chenghui,Wei Aixiang,Liu Jun,Zhao Yu,Xiao Zhiming
In this paper, a two-step method is used to prepare a high-quality CH 3 NH 3 PbI 3 layer for carbon-based hole conductor-free perovskite solar cells (PSCs). In the first step, the solvent for the PbI 2 /DMF solution is changed to a mixed solvent of N,N -dimethylformamide (DMF) with dimethyl sulfoxide (DMSO) from pure DMF solvent. This process requires 3.5 h for PbI 2 films deposited from the PbI 2 /DMF solution to completely convert to perovskite in a methyl amine iodide (MAI)/iso-propyl alcohol (IPA) solution, and perovskite films have a rough surface with a few large crystals. This mixed solvent accelerates the conversion of PbI 2 to CH 3 NH 3 PbI 3 , resulting in smooth CH 3 NH 3 PbI 3 films without residual PbI 2 . Only 15 min are required for PbI 2 films to completely convert to perovskite when the volume ratio of DMSO to DMF is 1:4. As a result, the photovoltaic performance, especially on the fill factor (FF) of PSCs fabricated from DMF/DMSO solvent, improved mainly due to the better contact of perovskite/carbon interface and faster charge transport of the perovskite layer.
研究领域:
材料科学
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能源技术
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产品关联
DOI
高影响因子
Soft Matter
·
2015
·Vol. 11
·期 31
·6266-6274
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IF 4.029
Chen Chen,Yue-Cheng Qian,Chuan-bin Sun,Xiao-Jun Huang
The amphiphilic random copolymer poly(β-D-glucose-co-1-octyl)phosphazene (PGOP) can undergo continuous morphological transitions in DMF–water mixed solvents. In this study, the ratio of glucose moieties to octyl moieties was controlled via a two-step thiol–ene reaction. As a result, polyphosphazenes with glycosyl functionalization degrees of 58.1% (PGOP-1), 74.1% (PGOP-2) and 87.0% (PGOP-3) were obtained. These amphiphilic polyphosphazenes self-assemble in both water and water–DMF mixtures. Several self-assembled morphologies including spheres, rods and vesicles were formed though careful control of the water content (WC) in the DMF solvent as well as of the hydrophilicity or hydrophobicity of the copolymers. We also found that an increase in the hydrophobic proportion led to faster morphological transitions at a constant WC. The thermodynamics of micellization were also studied by Isothermal Titration Calorimetry (ITC), and the strong hydrophobic interactions in PGOP-1 were demonstrated by their highly exothermic nature. These self-assemblies have potential applications in biosensing, lectin adsorption and drug loading with controlled release.
研究领域:
材料科学
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生物医学工程
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化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2024
·
IF 3.2
Ziqiang Zhang,Zhengfeng Shen,Chuanyu Zhu,Yunfang Wang,Yawen Wang,Caimei Fan,Rui Li,Jianxin Liu
Producing hydrogen from organic/inorganic hydrides is an innovative clean energy alternative to fossil fuels , addressing the increasing energy demands. Here, we first propose coupled photocatalytic water hydrogen production and N,N-dimethylformamide (DMF, C 3 H 7 NO) dehydrogenation technology to obtain high value-added H 2 and N,N-dimethylcarbamic acid (C 3 H 7 NO 2 ). ZnIn 2 S 4 @MIL-125(Ti) nanoheterostructures were synthesized using a simple solvothermal method and resulting in a photocatalytic H 2 production rate of 2.135 mmol h −1 g −1 (apparent quantum efficiency at 380 nm was 2.6 %) which is 2.77 times higher than pure ZnIn 2 S 4 . Liquid-phase mass spectrometry indicates that the DMF oxidation activity of ZIS@MIL heterojunction is double pure ZnIn 2 S 4 and only microcrystalline CO 2 is produced. Isotopes indicate that the production pathway of H 2 results from the coupling of the –CHO bond in DMF and the –H in water. The improved photocatalytic activity of the ZnIn 2 S 4 @MIL-125(Ti) heterostructure is attributed to facilitating efficient charge carrier transfer and separation and DMF depletion of holes accelerates electron transfer .
研究领域:
材料科学
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能源科学
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化学工程
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DOI
高影响因子
危险品化学品经营许可证（带存储）