JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2019
·Vol. 30
·期 4
·3365-3377
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IF 2.195
Shen Yongqian,Wei Yupeng,Li Jian,Li Qinglin,Ma Jiqiang,Wang Pingbo,Li Bin,He Wenbo,Du Xueyan
High-performance microwave absorbers with excellent absorption ability and superhydrophobic property are extremely significant for the application of stealthy techniques, especially in high-humidity environment. In this research, high-performance Co-C nanofibers (NFs) were prepared via electrospinning mathod by using of poly (vinyl alcohol) (PVA) and Cobalt acetate tetrahydrate (CoAc) solution as precursor with subsequent PVA pyrolyzation and carbonization process. The electromagnetic (EM) parameters and microwave absorption performance of the prepared NFs were investigated with the microwave frequency ranging from 2.0 GHz to 18.0 GHz. Analysis and comparison were performed on the impedance matching and loss mechanisms of each sample. The experimental results indicated that the sample calcinated at 950 °C achieved an optimal reflection loss (RL) of − 33.1 dB and an effective frequency bandwidth of 4.1 GHz under a thickness of 1.5 mm; and that the Co-C NFs membrane with the optimal absorption performance exhibited superhydrophobic property with a contact angle (CA) of 152°, suggesting their promising application to water-resistant stealthy materials.
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ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Mengmeng Shao,Yangfan Shao,Shengjie Ding,Rui Tong,Xiongwei Zhong,Lingmin Yao,Weng Fai Ip,Baomin Xu,Xing-Qiang Shi,Yi-Yang Sun,Xuesen Wang,Hui Pan
Searching photocatalysts for efficient hydrogen production has been a challenging issue for solar-energy harvesting. Using co-catalyst is proven to be an effective approach to improve the efficiency of photocatalyst in water-splitting. Here, we report that carbonized MoS2 (MoS2/Mo2C) can be a superactive co-catalyst in solar-driven hydrogen production. We show that MoS2/Mo2C decorated CdS achieves a high photocatalytic hydrogen evolution rate (34 mmol/h/g, ∼112 times higher than pure CdS) and excellent apparent quantum efficiency (41.4% at 420 nm). The outstanding photocatalytic performance of MoS2/Mo2C/CdS is attributed to the metallic characteristic of MoS2/Mo2C and suitable Gibbs free energy of hydrogen adsorption, leading to enhanced light absorption, fast separation and transportation of photoinduced carriers, and optimal activity in hydrogen evolution reaction (HER). We further show that MoS2/Mo2C as co-catalyst can also dramatically improve the photocatalytic activity of g-C3N4. Our findings demonstrate that the carbonized transition metal disulfide can be active as co-catalyst in photocatalysis, providing guidance on exploring novel photocatalysts for energy harvesting.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2019
·Vol. 30
·期 10
·9259-9265
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IF 2.195
Zhou Yujiu,Zhao Yuetao,Chen Fujia,Chen Yan,Liu Qingxia,He Xin,Mao Xiling,Yang Yajie,Xu Jianhua
The improvement of energy density is desired for dielectric materials in capacitors according to the developing trend of electric devices. In this article, poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-CTFE)) and polyurea (PUA) are blended in different ratios to obtain high dielectric performance composite, and the dielectric polymer composite films are fabricated and investigated. The composite films combine the advantages of both contents, showing high dielectric constant of P(VDF-CTFE) and high energy storage efficiency of PUA. The results demonstrate that the composite film contains PUA with a volume fraction of 10% exhibits the best performance, achieving a breakdown strength as high as 5020 kV/cm, which is higher than that of P(VDF-CTFE)/polythiourea (PTU) composite ever reported. Moreover, the breakdown strength and energy storage efficiency are 1.35 times and 1.65 times higher than pure P(VDF-CTFE), respectively. The article provides a new high-performance dielectric material fabricated through a simple and effective blending method, and it has a great potential in electric energy storage capacitors.
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CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Honghong Lei,Peng Jiang,Bin Li,Yuncheng Zhou,Rui Zhang,Jianlei Kuang,Wenbin Cao,Wei Wang
The (S, N) co-doped Ba 2 In 2- x Cr x O 5+ y (0 ≤ x ≤ 0.5) oxides are successfully obtained by mixing the Ba 2 In 2- x Cr x O 5+ y oxides and thiourea through a simple ball milling method followed by sintering at 400 °C for 3 h. The colors of the compounds change from orange-brown to yellow-green after reacting with thiourea. When Cr amount is small ( x = 0.1), the crystal structure of (S, N) co-doped Ba 2 In 2- x Cr x O 5+ y is orthorhombic Ba 2 In 2 O 5 phase. When x ≥ 0.3, the crystal structure of the sample is cubic BaInO 2.5 phase. And this phase transition is the same as Ba 2 In 2- x Cr x O 5+ y . XPS results reveal that Cr 6+ in Ba 2 In 2- x Cr x O 5+ y (0 ≤ x ≤ 0.5) oxides are reduced to Cr 3+ after sintering. S exists in both cation and anion forms, and N exists in substitutional forms. UV–Vis analysis indicates that the yellow-green hue comes from the d-d transition of Cr 3+ , and the doping of S, N ions leads to a red shift of the absorption edge of the samples.
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
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2019
·Vol. 139
·期 3
·1931-1939
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IF 2.471
Qu Dezhi,Gao Hongwei,Wang Qiuxia,Bai Yongping,Li Ning
Crystallization kinetics are very important for polymeric materials due to the fact that they determine the final degree of crystallinity and the morphology of the final product after processing. The kinetic of non-isothermal crystallization of poly(butylene-co-isosorbide succinate) (PBIS) was investigated using differential scanning calorimetry. Ozawa, Jeziorny and Mo methods were used to describe the non-isothermal crystallization process of PBIS. Both the Ozawa constant and the Avrami constant were obtained by Ozawa method and Jeziorny method, respectively. The crystallization activation energy (∆ E ) for non-isothermal crystallization process of PBIS, analyze based on the differential isoconversional method of Friedman and Kissinger, was found to increase with the relative crystallinity.
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CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2019
·Vol. 35
·期 2
·179-185
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IF 1.071
Jian Juan,Yuan Long,Li He,Liu Huanhuan,Zhang Xinghui,Sun Xuejiao,Yuan Hongming,Feng Shouhua
We used the one-step hydrothermal controlled synthesis method for Co-Ni 3 S 2 ultrathin nanosheets grown directly on nickel foam(NF). The as-synthesized Co-Ni 3 S 2 /NF showed enhanced activities in the hydrogen evolution reaction(HER), oxygen evolution reaction(OER) and better overall water splitting(OWS) efficiency than the un-doped Ni 3 S 2 /NF. The voltage of Co-Ni 3 S 2 /NF for OWS was only 1.58 V at the current density of 10 mA/cm 2 and with long time(>30 h) current output during the current-density( i - t ) test. The good i - t performance was also observed in both HER and OER processes. Additionally, the Co-Ni 3 S 2 /NF showed a large current density(>1 A/cm 2 ) for both HER and OER. When the current densities reached 100 and 1000 mA/cm 2 , the required overpotentials for Co-Ni 3 S 2 /NF were 0.35 and 0.75 V for OER and 0.30 and 0.85 V for HER. Therefore, after introducing Co, th e activity of Ni 3 S 2 -based material was strongly enhanced.
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EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
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2019
·Vol. 2019
·期 33
·3734-3739
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IF 2.578
Jie Hu,Mu Li,Kun Chen,Panchao Yin
Graphical A phase transfer approach to controllably assemble core-shell nanoparticles through two different sized CdSe QDs and tri-lacunary Keggin-type POMs functionalized with thiol groups. A co-assembly protocol of quantum dots (QDs)-polyoxometalates (POMs) hybrids is developed using Keggin-type POMs as surface capping ligands. Phase transfer strategy is used to prepare POM-QDs nanocomposites. These newly developed hybrid materials have been explored for their optical properties and aggregation behavior in solutions. UV/Vis and FT-IR are used to reveal the optical properties of POM-QDs. Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) are applied to characterize the co-assembled core-shell structures of POM-QDs complexes under different reaction conditions. A general trend to be noted is that the average photoluminescence (PL) lifetime of QDs decreases after phase transfer. The lifetime attenuation is caused by the surface property change of newly obtained POM-QDs complexes, which is resulted from the changed band edge recombination and shallow trap assisted recombination.
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NANOTECHNOLOGY
·
2019
·Vol. 30
·期 35
·355604
·
IF 3.399
Keju Zhang,Dong Zhou,Zhiguo Wang,Yuhong Zhang,Peixin He
The synthesis of drug delivery systems based on surface-modified mesoporous silica hollow structures remains a huge challenge. In this paper, we have obtained hollow mesoporous silica nanoparticles (MSNs) by surfactant directed sol-gel assisted hydrothermal treatment. The MSNs have the inorganic-organic hybrid frameworks with uniform diameter distribution (260 nm), and their specific surface area, mesoporous size and pore volume are 540 m2 g−1, 3.7 nm, 0.58 cm3 g−1, respectively. It was proved that the preparation of hollow ethane-bridged nanospheres with two silicon source was due to the high crosslinking of the silicone interface and hydrothermal treatment, providing a new approach for the study of drug-loaded and controlled release behavior. Based on the synthesis of MSNs, MSNs were modified by methacryloxy propyl trimethoxyl silane (MPS) on the surface of MSNs. Then N-isopropylacryamide (NIPAM) and acrylic acid (AA) were grafted onto the surface of modified MSNs. The hollow ethane-bridged PNA–MSNs (poly (NIPAM-co-acrylic acid)-MSNs) with two silicon source were prepared successfully. Due to their distinctive hollow structure, PNA–MSNs demonstrated high drug encapsulation efficiency (70.4% ± 2.9%). The experiment results proved that the modified hollow nanoparticles not only had good biocompatibility and stability, but also possessed pH-/thermal-dual responsiveness in drug release.
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PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Peiman Xu,Jinming Zhang,Zhifeng Ye,Yiyi Liu,Tianlun Cen,Dingsheng Yuan
Tailoring low-cost electrocatalysts with high activity and good stable for hydrogen evolution reaction (HER) is vital to energy harvesting and storage. Herein, Co doped Ni 0.85 Se nanoparticles supported on reduced graphene oxide (Co Ni 0.85 Se/RGO) were synthesized by a facile one-step hydrothermal method . As expected, the resulting hybrid materials effectively inhibit the aggregation of nanoparticles and possess the enhanced intrinsic conductivity, leading to exposure of more active sites and the faster electron transport . And then these beneficial effects enable Co Ni 0.85 Se/RGO efficient HER catalytic activity in both acid and basic electrolytes, achieving small overpotentials of 148 and 128 mV at a current density of 10 mA cm − 2 in 0.5 M H 2 SO 4 and 1.0 M KOH, respectively.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2019
·
IF 3.131
Nana He,Lili Li,Panpan Wang,Junhao Zhang,Jiaqi Chen,Jie Zhao
Herein, titanium dioxide/chitosan/poly(lactide-co-caprolactone) (TiO 2 /CS/P(LLA-CL)) composite membranes with highly efficient adsorption of copper ions (Cu(II)) in aqueous solution were developed, through a facile electrospinning method. First, TiO 2 nanoparticles were ultrasonically dispersed in CS/P(LLA-CL) solution to get a uniform suspension. Afterwards, the mixture was applied for electrospinning to generate the smooth and bead-free composite membranes. The high adsorption capability of the composite membranes on Cu(II) was mainly attributed to the combination of TiO 2 nanoparticles, CS/P(LLA-CL) matrix and nanosized membrane. Among those, the TiO 2 /CS/P(LLA-CL) composite membrane with 2% TiO 2 content demonstrated the maximum adsorption capability (˜190.5 mg g −1 ) for Cu(II) from aqueous solution. Their adsorption behaviors were well conformed to pseudo-second-order kinetic model and Langmuir isotherm model. Moreover, FTIR and XPS results confirmed the existed chelation and ion exchange between the membrane and the Cu(II) during adsorption process. Due to its simplicity, effectiveness and stability in water, this type of composite membrane may serve as a promising environmentally-friendly and non-toxic adsorbent for removal of Cu(II) in aqueous.
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POLYMER
·
2019
·
IF 3.771
Longfei Li,Hong Zhai,Tao Wang,Xibo Qiu,Na Qiang,Peng Dong,Ying Bai,Ai-Yun Peng,Daping Quan
The ring-opening copolymerization of lactide with carbonate is an available strategy to incorporate reactive groups to the pendent sites of copolymer for further functional modification. A series of random and block copolymers were synthesized from l -lactide ( L -LA) and 2-bromomethyl-2-methyltrimethylene carbonate (BMTC) using dodecanol as initiator and stannous octoate as catalyst. The structures of the copolymers were characterized by nuclear magnetic resonance ( 1 H NMR, 13 C NMR), gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). The composition of the copolymers can be controlled through changing the feed ratios of n BMTC / n L -LA . It was found the random P(BMTC- co - L LA) copolymers had the semicrystalline characteristic due to the relative long block-like segments of P L LA ( L L , P L LA = 5.3–7.3) and the polar interactions from bromo groups , but their crystallinity ( X c, P L LA ) and melting temperature ( T m, P L LA ) decreased when the BMTC content increased. The X c, P L LA and T m, P L LA of P(BMTC- b -P L LA) block copolymers were relatively higher than the corresponding random copolymers, and approached gradually to the pure P L LA with the increase of the molecular weight of P L LA block. Finally, the pendent bromo groups of P(BMTC- co - L LA) were easily transformed into azides , which could proceed the azide-alkyne click reaction smoothly and quantitatively at room temperature .
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JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 102
·期 12
·7491-7499
·
IF 3.094
Ziyu Liu,Guido Toci,Angela Pirri,Barbara Patrizi,Jinbang Li,Zewang Hu,Jiabei Wei,Hongming Pan,Tengfei Xie,Matteo Vannini,Jiang Li
In this article, 5 at.% Yb:Lu 2 O 3 transparent ceramics were fabricated by vacuum sintering combined with hot isostatic pressing (HIP) posttreatment using co-precipitated nano-powders. The influence of precipitant molar ratio, ammonium hydrogen carbonate, to metal ions (AHC/M 3+ , R value) on the properties of Yb:Lu 2 O 3 precursors and calcined powders was investigated systematically. It was found that the powders with different R value calcined at 1100°C for 4 hours were pure cubic Lu 2 O 3 but the morphologies of precursors and powders behaved differently. The opaque samples pre-sintered at 1500°C for 2 hours grew into transparent ceramics after HIP posttreatment at 1750°C for 1 hour. The final ceramic with R = 4.8 showed the best optical quality with the in-line transmittance of 79.7% at 1100 nm. The quasi-CW laser operation was performed at 1034 nm and 1080 nm with a maximum output power up to 8.15 W as well as a corresponding slope efficiency of 58.4%.
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危险品化学品经营许可证（带存储）