JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Mingye Ding,Chunhua Lu,Le Chen,Zhenguo Ji
Traditional FIR (fluorescence intensity ratio)-based optical thermometers, requiring narrow energy gap between two thermally coupled states (TCS) of single rare-earth ion, have inherent drawbacks including low signal discriminability and large measuring error. To overcome the intrinsic limitation, a new thermometry strategy involving the usage of dual-emitting activators with diverse temperature-dependent emission behaviours has been proposed. Impressively, β-NaYF 4 :Ce 3+ /Tb 3+ phosphor exhibits good temperature sensing performance, excellent signal discriminability and superior thermal stability by using the linearly temperature-dependent FIR between Ce 3+ and Tb 3+ as detecting parameter. Hopefully, the developed dual-emitting sample could have a promising application in self-calibrated luminescent thermometry and this strategy provides a reference for developing high-performance optical thermometers.
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高影响因子
Journal of Macromolecular Science Part B-Physics
·
2021
·
IF 1.504
Chenmeng Zhou,Xuzhen Zhang
Acetylated cellulose nanocrystals (ACNC) were prepared by surface modifying cellulose nanocrystals (CNC) with acetic anhydride (AA). By adding ACNC into biodegradable poly(butylene succinate-co-butylene adipate) (PBSA), ACNC/PBSA composites were prepared via a melt blending method. The structure and morphology of the ACNC were analyzed by Fourier transform infrared (FTIR) spectroscopy, wide angle X-ray diffraction (WAXD) analysis, field emission scanning electron microscopy (FE-SEM) and contact angle measurements. The results showed that the CNC were successfully modified by acetic anhydride, while maintaining their original nanosize rod shape of CNC and showing obvious hydrophobicity. SEM images of the ACNC/PBSA composites indicated that the ACNC were homogeneously dispersed in the composites. With increasing ACNC content, the crystalinity, melt viscosity and decomposition starting temperature increased gradually. In addition, the tensile strength of the ACNC/PBSA composites showed a maximum value at a ACNC content of 3.0%, which was 26.3% higher than for pristine PBSA but the elongation at break was 20% lower than for pristine PBSA.
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高影响因子
Journal of Macromolecular Science Part B-Physics
·
2017
·
IF 0.828
Shan Bai,Zhenzhong Ouyang
Direct graft copolymerization of maleic anhydride (MAH) onto poly(D,L-lactide-co-glycolide) (PLGA) was performed by use of benzoyl peroxide (BPO) as initiator. Fourier transform infrared spectra, nuclear magnetic resonance, titration analysis of maleation extent and water contact angle were employed to characterize the obtained MPLGA. The effects of monomer concentration, initiator concentration and reaction temperature on the degree of maleation were investigated. The MPLGA scaffold was obtained by using NaCl as the porogen. The results showed that maleic anhydride was successfully grafted onto the PLGA chains. The monomer and initiator concentrations played an important role in the graft copolymerization; the extent of maleation first increased with increasing content of MAH and BPO and then declined. The extent of maleation continuously increased with increasing temperature to 100°C, and then the rate of increase decreased. The extent of maleation could be controlled in the range from 0.15 to 0.71% by adjusting the graft copolymerization conditions. The introduction of anhydride enhanced the water contact angle of PLGA. The MPLGA scaffold showed a network of interconnected pores ranging from 50 to 300 μm.
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高影响因子
NANO
·
2021
·
IF 1.556
Ye Shang,Manfei Lv,Songtian Li
A new type of pure organic 5,10,15,20-tetra (4-hydroxyphenyl) porphyrin (TPPH)/ g -C 3 N 4 nanohybrid was prepared to expand the light absorption range of graphitic carbon nitride materials. The morphology and structure of the composites were systematically characterized by scanning electron microscope, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Results show that after the introduction of TPPH, the visible light area optical absorption of the composite sample increased significantly under the noncovalent interaction of TPPH and g -C 3 N 4 , and the electrochemical impedance spectroscopy and I – T measurements confirmed the improved charge separation efficiency of the sample and showed excellent photocatalytic hydrogen production capacity. Under full spectrum irradiation, the hydrogen production of 1.67% TPPH/ g -C 3 N 4 without adding co-catalyst reached 10.87 mmol ⋅ g − 1 ⋅ h − 1 , about 2.68 times that of pure g -C 3 N 4 (4.06 mmol ⋅ g − 1 ⋅ h − 1 ), which showed effective promotion of the electron transfer between TPPH and g -C 3 N 4 .
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高影响因子
ChemElectroChem
·
2017
·Vol. 5
·期 2
·242-246
·
IF 4.136
Mei Guo,Chaochao Qiu,Yu Li,Xiuyan Jin,Guoxin Zhang,Xiaoming Sun
Herein, defect-rich graphene oxide with a crumpled form was fabricated through the fast thermal expansion of H 2 SO 4 -intercalated graphite oxide. The fast removal of intercalated H 2 SO 4 molecules and by-product gases result in the formation of crumpled edges, whereas the partial reduction of H 2 SO 4 leads to a large amount of defects and minor S doping (ca. 0.55 at%). The expanded graphene oxide with a crumpled form and rich defects was used as electrode materials for the oxygen reduction reaction (ORR), and a very high ORR performance was observed in 0.1 mol L −1 KOH, exhibiting an onset potential of 0.92 V, a half-wave potential of 0.83 V, and a roughly 5.68 mA cm −2 limiting current density with catalyst loading of 0.1274 mg cm −2 . Our work provides reliable GO-based catalyst materials for the ORR; moreover, it will expand the knowledge one type of high-activity site for the ORR: defects on crumpled edges. Graphical In a crump : Defect-rich crumpled graphene oxide (CGO) is fabricated by using a modified Hummers method, followed by fast thermal treatment. Abundant defective and doping sites are created, presenting on the crumpled edges. Highly comparable oxygen reduction reaction performance of the CGO is demonstrated relative to commercial Pt/C.
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高影响因子
WATER SCIENCE AND TECHNOLOGY
·
2021
·Vol. 84
·期 1
·251-261
·
IF 1.915
Hu Chunlian,Zhang Wei,Chen Yuantao,Ye Na,YangJi DaWa,Jia Haizhe,Shen Yanting,Song Minna
Here adsorption studies were proposed on a carboxylated sludge biochar (CSB) material modified by HNO 3 to assess its capacity in the removal of cobalt from aqueous solution. The as-prepared sludge biochar material was characterized by Brunauer-Emmett-Teller (BET) analysis, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The isotherm process could be well described by the Langmuir isotherm model. The adsorption kinetics indicated that cobalt adsorption followed a pseudo-second-order kinetics model. The mechanism between Co(II) and biochar involved electrostatic interaction, ion exchange, surface complexation and physical function. The adsorption capacity on CSB was as high as 72.27 mg·g −1 , surpassing original sludge biochar (SB) as CSB had abundant oxygen-containing functional groups and many hydroxyls, plus the BET surface areas increased when SB was modified by HNO 3 , which stimulated adsorption effect. Therefore, this work shows that CSB could be used as an efficient adsorbent to remove Co(II) in wastewater. The material has abundant oxygen-containing functional groups, which are beneficial for binding Co(II). The isotherm process could be well described by the Langmuir isotherm model and pseudo-second-order kinetic model. The adsorbent has an efficient adsorption capacity for Co(II), as high as 72.27 mg·g −1 .
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高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
·
2020
·
IF 4.006
Chenglin Cao,Yuyuan Wang,Shaoming Zheng,Jie Zhang,Wei Li,Baobi Li,Ruijie Guo,Jun Yu
Poly (butylene adipate- co -terephthalate) (PBAT)/titanium dioxide (TiO 2 )/silver (Ag) composite biofilms were prepared via a common solvent casting method and then used for food packaging. The effects of TiO 2 /Ag nanoparticles on the physical, antibacterial, and antiseptic properties of the composite biofilms were comprehensively investigated. Results showed that the physical properties, such as mechanical, UV blocking, and barrier properties, of PBAT matrix were remarkably improved by the incorporation of TiO 2 /Ag nanoparticles . The optimum performance was achieved when the concentration of TiO 2 /Ag nanoparticles was 5% (w/w). Given the excellent antibacterial activity of TiO 2 /Ag nanoparticles, the composite biofilms exhibited unique antibacterial performance against Escherichia coli and Staphylococcus aureus . In addition, the results of the cherry tomato preservation experiment indicated that the composite biofilms possessed good food preservation ability, which ensures that the present composite biofilms can be utilized in the food packaging industry.
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高影响因子
CERAMICS INTERNATIONAL
·
2023
·Vol. 50
·期 1
·799-809
·
IF 5.2
Huan Zhong,Yunzhong Liu,Zhiguang Zhou,Zhenhua Fan,Zhiheng Shu,Lidong Wu
High fracture toughness and excellent hydrothermal aging resistance are the characteristics required for dental ceramic materials, but the widely used dental ceramic currently (3Y-TZP) does not exhibit. Aiming to solve this problem, a ternary rare earth co-stable zirconia ceramic (1.5Y5.5Ce0.3La-ZrO 2 ) was prepared by a coating method based on a co-doping strategy. The sintering process, densification evolution, mechanical properties, resistance to hydrothermal aging and biocompatibility of 1.5Y5.5Ce0.3La-ZrO 2 ceramic were studied. The results show that 1200 °C is the best pre-sintering temperature, and the machinability and controllability of shrinkage can meet the needs. When the final sintering temperature is 1600 °C, it has the best performance. Compared with 3Y-TZP, the bending strength is about 8.7% higher (912.48 MPa), and the fracture toughness is about 76.6% higher (10.49 MPa m 1/2 ). Furthermore, its resistance to hydrothermal aging is significantly enhanced, greatly extending the service life of the material. The biosafety of 1.5Y5.5Ce0.3La-ZrO 2 ceramics was evaluated, and the results showed that the material had no cytotoxicity. To sum up, 1.5Y5.5Ce0.3La-ZrO 2 ceramics is a promising dental biomaterial, which has a broad application prospect in oral restoration.
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高影响因子
Journal of Materials Chemistry C
·
2015
·Vol. 3
·期 38
·9885-9893
·
IF 4.696
Quan Xu,Yao Liu,Chun Gao,Jianfei Wei,Hongjun Zhou,Yusheng Chen,Chenbo Dong,Theruvakkattil Sreenivasan Sreeprasad,Neng Li,Zhenhai Xia
Heteroatom doped carbon dots (CDs) with consummate photoluminescence quantum yield (PLQY) are of great interest in various applications such as trace element detection, biomolecule markers, and chemical sensing. However, due to the low doping efficiency of the reaction, a high precursor ratio is routinely used to obtain CDs with considerable photoluminescence quantum yield (PLQY). In this contribution, we report a single-step hydrothermal method having the highest doping efficiency to synthesize sulfur and nitrogen co-doped semi-crystalline carbon dots (S,N-CDs) with superior quantum yield (QY). Here, the unprecedented doping efficiency of the reaction enables an order of magnitude reduction in the starting precursor ratio, in comparison with previous reports. Moreover, for the first time, complementary theoretical and comprehensive spectroscopic techniques were employed to derive deep insight into the photoluminescence mechanism and the shifting of specific energy levels in doped CDs was identified as the reason behind the enhanced photoluminescence of doped CDs. The PLQY and luminescent characteristics of the S,N-CDs can be tuned by controlling the precursor molar ratio, the extent of surface oxidation, and chemical status of S in the CDs. While most methods report high PLQY for amorphous CDs, our technique produces semi-crystalline CDs with more than 55% QY. Another unique attribute of the S,N-CDs is the high monodispersity and defined surface chemistry and the resultant highly robust excitation-independent luminescence that is stable over a broad range of pH values and in an extremely reactive environment. The detailed structural and chemical investigations using spectroscopic and microscopic techniques combining molecular simulation revealed that the superior PLQY and luminescence of S,N-CDs are due to the heteroatom directed, oxidized carbon-based surface passivation. The remarkable, robust fluorescence properties of S,N-CDs were applied for the ultra-trace detection of Hg2+ with a detection limit of 100 pM. The novel insights into the photoluminescence of doped CDs, the robust luminescence, and enhanced doping reaction efficiency reported here are envisaged to drive transformative changes in the design of CDs with peerless properties for futuristic applications.
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高影响因子
JOURNAL OF ORGANIC CHEMISTRY
·
2015
·
IF 4.721
Guangwei Rong,Jincheng Mao,Hong Yan,Yang Zheng,Guoqi Zhang
A new approach to the selective synthesis of (E)-vinyl sulfones has been developed via a Fe/Cu co-catalyzed sulfonylation of arylpropiolic acid or phenylacetylene with sulfonyl hydrazides. A variety of vinyl sulfones have been obtained in moderate to good yields, comparable to the best results reported so far. The inexpensive Fe/Cu co-catalyzed method features a simple experimental procedure and good tolerance of substrate.
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高影响因子
Nano Energy
·
2018
·
IF 13.12
Li An,Jianrui Feng,Yu Zhang,Yong-Qing Zhao,Rui Si,Gui-Chang Wang,Fangyi Cheng,Pinxian Xi,Shouheng Sun
Transition-metal nitrides (TMNs), especially iron-based TMNs, have high electrical conductivity , superior chemical stability and unique oxygen-reaction ability, and have emerged as a new form of noble metal-free electrocatalysts . In this paper, we demonstrate that the ORR-active/OER-inert single function catalyst Fe-N can be made as the OER/ORR-active bifunctional catalyst Co-Fe-N by controlled substitution of Fe with Co. To obtain atomic insights of the Co-enhanced OER catalysis, we develop a new exfoliation method to prepare atomically thin (1.1 nm) nanosheets (NSs) of Co x Fe 1-x N 0.5 (x = 0, 0.05, 0.1, 0.15 and 0.2). Our studies show that both electronic structure and local binding environment of Fe are modified by Co substitution and the Co-Fe-N NSs show a volcano−like OER catalysis with Co 0.15 Fe 0.85 N 0.5 NSs being the most efficient OER catalyst, showing the lowest overpotential of 266 mV at 10 mA cm −2 , a Tafel slope of ∼30 mV dec −1 , and excellent stability in the 1.0 M KOH OER condition. Density functional theory (DFT) calculations suggest that the Co-Fe sites in the Co 0.15 Fe 0.85 N 0.5 structure are optimized to promote OH* to O* conversion, O*-O* coupling and O 2 formation. The Co 0.15 Fe 0.85 N 0.5 NSs are a class of new noble-metal-free catalyst for OER.
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高影响因子
ACS Applied Energy Materials
·
2018
·
IF 0
De-Yin Wang,Peng-Cheng Ma,Jia-Chi Zhang,Yu-Hua Wang
Samples of Er3+–Yb3+ co-doped Y7O6F9 are synthesized by solid state reaction method, and their down- and up-conversion luminescence are studied. Upon excitation into the 4F7/2 level of Er3+ at 490 nm, effective energy transfer from Er3+ to Yb3+ via cross-relaxation Er3+ (4S3/2) + Yb3+ (2F7/2) → Er3+ (4I13/2) + Yb3+ (2F5/2) occurs, splitting an absorbed high-energy photon (λ = 490 nm) into two photons (λ = 1000 and 1540 nm). Based on the changing of the lifetime of Er3+4S3/2 → 4I15/2 emission without and with Yb3+, the efficiency of Er3+ → Yb3+ energy transfer in Y7O6F9:1%Er3+,9%Yb3+ has been evaluated to 58%. Upon excitation at 980 nm, as the Yb3+ doping concentration increases, not only an overall increase in intensity but also an enhancement of the red (4F9/2 → 4I15/2) emission with respect to the green (4S3/2 → 4I15/2) emission were observed. Under 980 nm laser excitation with power of 20 mW, the overall integrated emission intensity in the 500–700 nm of Y7O6F9:1%Er3+,5%Yb3+ is 1.8 times higher than that of β-NaYF4:2%Er3+,18%Yb3+ that is to date the most efficient up-conversion phosphor. In view of the efficient down-/up-conversion in Er3+-Yb3+ co-doped Y7O6F9, this material is expected to be used to enhance the efficiency of solar cells.
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