JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 24
·20580-20587
·
IF 2.324
Fang Lu,Xue Yan,Hu Xing-Ming,Xie Dong,Li Wen-Jun
Electrochemiluminescence (ECL) is a very sensitive method for trace analysis because of its background interference and high signal-to-noise ratio. In the past decade, the determination of Cu 2+ in environment has attracted considerable attention since it plays an essential role in many physiological processes. Herein, a novel ECL sensor based on C,N quantum dots embedded g-C 3 N 4 nanosheets (C,N-QDs@NSs) was constructed for the detection of Cu 2+ . The nanocomposite was rapidly obtained via the oxidation of normal g-C 3 N 4 in H 2 O 2 solution using sonochemical synthesizing method. Due to the abundant surface defects on C,N-QDs@NSs, the ECL intensity was magnified 2.5 times for using a C,N-QDs@NSs electrode in comparision to a g-C 3 N 4 modified electrode. Besides, C,N-QDs@NSs could accelerate the rate of electron transfer in ECL reaction and thus resulted in the lower cathodic peak potential. Significantly, Cu 2+ could effectively quench the ECL of C,N-QD@NSs, which endowed C,N-QD@NSs with a great advantage in the ECL detection of Cu 2+ . under optimum conditions, C,N-QDs@NSs modified electrode exhibited a linear detection range from 5 × 10 −4 to 10 µM with a detection limit of 2 × 10 −4 µM (S/N = 3) for Cu 2+ , and was finally applied to detect Cu 2+ in real samples with satisfactory results.
✓ 已验证
产品关联
DOI
高影响因子
Journal of the American Chemical Society
·
2015
·
IF 12.113
Xiao-Li Pei,Yang Yang,Zhen Lei,Shan-Shan Chang,Zong-Jie Guan,Xian-Kai Wan,Ting-Bin Wen,Quan-Ming Wang
The activation of C(sp3)–H bonds is challenging, due to their high bond dissociation energy, low proton acidity, and highly nonpolar character. Herein we report a unique gold(I)–silver(I) oxo cluster protected by hemilabile phosphine ligands [OAu3Ag3(PPhpy2)3](BF4)4 (1), which can activate C(sp3)–H bonds under mild conditions for a broad scope of methyl ketones (RCOCH3, R = methyl, phenyl, 2-methylphenyl, 2-aminophenyl, 2-hydroxylphenyl, 2-pyridyl, 2-thiazolyl, tert-butyl, ethyl, isopropyl). Activation happens via triple deprotonation of the methyl group, leading to formation of heterometallic Au(I)–Ag(I) clusters with formula RCOCAu4Ag4(PPhpy2)4(BF4)5 (PPhpy2 = bis(2-pyridyl)phenylphosphine). Cluster 1 can be generated in situ via the reaction of [OAu3Ag(PPhpy2)3](BF4)2 with 2 equiv of AgBF4. The oxo ion and the metal centers are found to be essential in the cleavage of sp3 C–H bonds of methyl ketones. Interestingly, cluster 1 selectively activates the C–H bonds in −CH3 rather than the N–H bonds in −NH2 or the O–H bond in −OH which is traditionally thought to be more reactive than C–H bonds. Control experiments with butanone, 3-methylbutanone, and cyclopentanone as substrates show that the auration of the C–H bond of the terminal methyl group is preferred over secondary or tertiary sp3 C–H bonds; in other words, the C–H bond activation is influenced by steric effect. This work highlights the powerful reactivity of metal clusters toward C–H activation and sheds new light on gold(I)-mediated catalysis.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ELECTROANALYSIS
·
2013
·Vol. 25
·期 6
·1400-1409
·
IF 2.817
Yonghai Song,Hongyu Liu,Lingli Wan,Yu Wang,Haoqing Hou,Li Wang
A novel biosensor was developed by entrapping cytochrome c (Cyt c ) in thin films of the room temperature ionic liquid (RTIL) containing nanocomposites of poly(diallyldimethylammonium chloride)-graphene nanosheets-gold nanoparticles (PDDA-Gp-AuNPs) at a 11-mercaptoundecanoic acid-6-mercapto-1-hexanol modified gold electrode. The synthesized PDDA-Gp-AuNPs hybrid nanocomposites were characterized by UV-vis spectroscopy, Raman spectroscopy, scanning electron microscopy and atomic force microscopy. The PDDA-Gp-AuNPs nanocomposites could increase the effective surface of the electrode, enhance the fixed amount of Cyt c on the electrode surface, promote the electron transfer and facilitate the catalytic activity of Cyt c . The RTIL could provide a biocompatible microenvironment to keep Cyt c biological activities, act as an effective mediator to immobilize a large number of Cyt c on the electrode and have good conductivity to improve electron transfer. Therefore, the resultant electrode exhibited good electrochemical performance and electrocatalytic activity. It could be used for electrochemical detection of H 2 O 2 with rapid response, high sensitivity, wide linear range and low detection limit, as well as good stability, repeatability and selectivity. The sensor might be promising for practical application.
✓ 已验证
产品关联
DOI
高影响因子
THIN SOLID FILMS
·
2014
·
IF 1.867
Kui Cheng,Xiaozhao Wang,Wenjian Weng,Jun Lin,Huiming Wang
Light-induced cell detachment on the substrate of TiO 2 nanodots has been proved to be a safe and attractive method for cell harvesting in tissue engineering. In order to improve the cell release efficiency, bioinert platinum with excellent charge transport loading in biocompatible graphite was prepared. 20 wt.% Pt/C powder showing excellent electrical, chemical and bioactive properties was incorporated to a TiO 2 system. We investigated the biocompatibility of Pt/C–TiO 2 composite films with different amounts of Pt/C with C/tetrabutyl titanate molar ratio varying from 0 to 0.42. The adhesion and proliferation rates of pre-osteoblastic MC3T3-E1 cells (mouse calvaria-derived) on the films prepared with the highest C/TiO 2 molar ratio are higher than that of the pure TiO 2 and other films, indicating a Pt/C dose-dependent effect. It is shown that the detachment efficiency of MC3T3-E1 cells depends on Pt/C amount and UV illumination time. Moreover, films prepared with C/tetrabutyl titanate molar ratio of 0.42 showed 93% cell detachment ratio within 5 min of UV illumination, while bare TiO 2 films only reached 75%, indicating an improved cell release efficiency by the incorporation of Pt/C. However, an interesting phenomenon was found that longer illumination time showed lower detachment ratios to some extent, which is contrary to our previous work. It is believed that this work presents the improved cell detachment efficiency by the incorporation of Pt/C.
✓ 已验证
产品关联
DOI
高影响因子
BIOSENSORS & BIOELECTRONICS
·
2014
·
IF 6.451
Chunjing Zhang,Shihui Si,Zhengpeng Yang
Combining the surface modification and molecular imprinting technique, a novel photoelectrochemical sensing platform with excellent photochemical catalysis and molecular recognition capabilities was established for the detection of uric acid based on the magnetic immobilization of Fe 3 O 4 @C nanoparticles onto magnetic glassy carbon electrode (MGCE) and modification of molecularly imprinted TiO 2 film on Fe 3 O 4 @C. The developed biosensor was highly sensitive to uric acid in solutions, with a linear range from 0.3 to 34 µM and a limit of detection of 0.02 μM. Furthermore, the biosensor exhibited outstanding selectivity while used in coexisting systems containing various interferents with high concentration. The practical application of the biosensor was also realized for the selective detection of uric acid in spiked samples. The study made a successful attempt in the development of highly selective and sensitive photoelectrochemical biosensor for urine monitoring.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2013
·
IF 4.093
Guang Lu Han,Ke Zhou,Ao Nan Lai,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
As a new type of filler for mixed matrix membranes (MMMs), metal–organic frameworks (MOFs) have received increasing attention. As a kind of MOFs, [Cu 2 (bdc) 2 (bpy)] n is successfully synthesized in this work and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), wide angle X-ray diffraction (WAXRD), thermogravimetric analysis (TGA) and adsorption isotherms . [Cu 2 (bdc) 2 (bpy)] n is found to preferentially adsorb methanol (MeOH) over methyl tert -butyl ether (MTBE). For this reason, the [Cu 2 (bdc) 2 (bpy)] n is incorporated into sulfonated polyarylethersulfone with cardo (SPES-C) to form [Cu 2 (bdc) 2 (bpy)] n /SPES-C MMMs for the separation of MeOH/MTBE mixtures. Both the sorption selectivity and the diffusion selectivity are found to increase with the addition of [Cu 2 (bdc) 2 (bpy)] n leading to an increase in the separation factor. With increasing [Cu 2 (bdc) 2 (bpy)] n loading from 5 to 20 wt%, the flux increased up to 0.288 kg m −2 h −1 at 20 wt% loading. A threshold of [Cu 2 (bdc) 2 (bpy)] n loading is approximately 20 wt% where the flux remains almost constant regardless of further increasing the [Cu 2 (bdc) 2 (bpy)] n content. This work demonstrates an improved performance of the [Cu 2 (bdc) 2 (bpy)] n /SPES-C MMMs for the separation of MeOH/MTBE mixtures.
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 75
·40019-40028
·
IF 3.708
Wei Zhong,Ying Yu,Chun Du,Wei Li,Yinzhen Wang,Guannan He,Yuandong Xie,Qinyu He
Buoyant photocatalysts which are able to remove organic pollutants under all lighting and weather conditions are in demand for the treatment of large volumes of organic wastewater. Buoyant carbon and nitrogen co-doped TiO2/polytetrafluoroethylene (NCT/PTFE) flakes which meet these requirements were prepared by the high-energy ball-milling of NCT powder and PTFE. The physicochemical properties of the as-prepared composite flakes were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible diffuse reflection spectroscopy (UV-vis DRS), Brunauer–Emmett–Teller (BET) surface area determination, and X-ray photoelectron spectroscopy (XPS), as well as electrical conductivity and density measurements. The density of the composite flakes was 0.93 g cm−3, slightly lower than that of water, rendering them buoyant. And the used-and- regenerated (by UV-vis irradiation for 8 h) flakes are also buoyant. Adsorption in the dark and photodegradation experiments indicated that the as-prepared flakes have high dark adsorption and high photocatalytic properties. The 6 h photodegradation ratio of methylene orange (20 mg L−1, 100 mL, as a model dye) is 96.6%, and a close degradation ratio of 97% can be obtained by three-cycle dark adsorption with minor stirring (1 cycle includes 8 h dark adsorption followed by 8 h regeneration by UV-vis irradiation per cycle). The high adsorption and good photocatalytic properties can be mainly attributed to the large BET surface area resulting from the small NCT particle size. The as-prepared flakes have the potential for use in organic pollutant adsorption at any time and can be regenerated through light irradiation when sunlight is available. This kind of environmental protection material has great practical significance due to its low cost, simple preparation, thermal durability, highly efficient organic pollutant removal, large-volume treatment capacity, recyclability, and the possibility of working at any time.
✓ 已验证
产品关联
DOI
高影响因子
COLLOID AND POLYMER SCIENCE
·
2014
·Vol. 292
·期 12
·3085-3093
·
IF 2.41
Huang Haibin,Chen Qinhui,He Junhui,Zheng Longhui,Chen Baoling,Lin Jinhuo
Janus materials with anisotropic chemical structures and physical properties have attracted increasing attention due to their diversified potential applications. In this paper, titanium dioxide/3-(trimethoxysilyl) propylmethacrylate (TiO 2 /MPS) was obtained by swelling assisted with extrusion of PS@TiO 2 . Then, the phenolic resin (PF) was coated on the surface of MPS lobe. Finally, TiO 2 /C Janus composite particles were obtained by sintering at the atmosphere of nitrogen. The middle objects during reactive process and the final product were systematically characterized. Results showed that the Janus porous particles of TiO 2 /C were snowman-like structure, in which the average diameter of the carbon lobe was 178 nm and that of TiO 2 lobe was 226 nm. When used as photocatalysts for Rhodamine B degradation in aqueous solution under UV irradiation, the resulted Janus product exhibited more efficient photocatalytic activity than TiO 2 hollow microspheres.
Schematic illustration of swelling polymerization approach to synthesize TiO 2 /C Janus composite particles and its photocatalytic activity for the degradation of rhodamine B
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2014
·
IF 7.572
Mei-Qing Wang,Wei-Hua Yang,Hong-Hui Wang,Chi Chen,Zhi-You Zhou,Shi-Gang Sun
Aimed at developing a highly active and stable non-precious metal catalyst (NPMC) for oxygen reduction reaction (ORR) in acidic proton-exchange membrane fuel cells (PEMFCs), a novel NPMC was prepared by pyrolyzing a composite of carbon-supported Fe-doped graphitic carbon nitride (Fe–g-C3N4@C) above 700 °C. In this paper, the influence of the pyrolysis temperature and Fe content on ORR performance was investigated. Rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) studies reveal that, with a half-wave potential of 0.75 V [versus reversible hydrogen electrode (RHE)] and a H2O2 yield of 2.6% at 0.4 V, the as-synthesized catalyst heat-treated at 750 °C with a Fe salt/dicyandiamide (DCD) mass ratio of 10% displays the optimal ORR activity and selectivity. Furthermore, the pyrolyzed Fe–N–C composite exhibits superior durability in comparison to that of commercial 20 wt % Pt/C in acidic medium, making it a good candidate for an ORR electrocatalyst in PEMFCs.
✓ 已验证
产品关联
DOI
高影响因子
Soft Matter
·
2013
·Vol. 9
·期 48
·11585-11597
·
IF 3.909
Wenlong Li,Peiyi Wu
The dynamic thermally reversible phase transition behaviour of poly(ethylene oxide) (PEO) in 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) has been investigated by calorimetric measurements (DSC) and FT-IR, in combination with perturbation correlation moving window (PCMW) and two-dimensional correlation spectroscopy (2DCOS) for the first time. A relatively high lower critical solution temperature (LCST) was observed which is different from that of conventional thermo-sensitive polymers in aqueous solution. Four types of hydrogen bonds were found in this system, among which the type I (the hydrogen bonds between the unsaturated C–H on the imidazole ring and the oxygen atoms of PEO) and type II (the hydrogen bonds between the saturated C–H on the PEO backbone and the fluorine atoms of the IL anions) ones have a more predominant influence on the phase transition. Moreover, type I plays the predominant role in both the heating and cooling process. DSC revealed that the phase transition temperature of PEO–[EMIM][BF4] solutions decreases with the increasing concentration of PEO, as well as with a decreasing scanning rate. Through PCMW, the LCST was determined to be ca. 137 °C during heating and ca. 131 °C during cooling. Finally, 2DCOS was employed to elucidate the dynamic mechanism of PEO in [EMIM][BF4], which revealed hydrogen bond disruption, chain aggregation and exclusion of IL molecules. Solutions with a low PEO concentration tend to form loosely aggregated globules, compared to the more densely aggregated globules in samples with a high PEO concentration. Additionally, it is worth mentioning that several unusual and peculiar phenomena were also observed, such as opposite frequency shifts in C–H groups, a “tail-raising” phenomenon, critical PEO concentration for the phase transition temperature, and intersection of the frequency shift curves for samples with high concentrations of PEO during cooling.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2015
·
IF 2.999
Yanqin Yang,Mengmeng Kang,Shaoming Fang,Minghua Wang,Linghao He,Xiaozhong Feng,Jihong Zhao,Zhihong Zhang,Hongzhong Zhang
It is highly desirable and a popular topic in scientific research to develop a highly sensitive and selective detection and quantitative analysis method of determining trace silver ions (Ag + ) in aqueous media since Ag + ions are recognized as one of the most hazardous metal pollutants. Three-dimensional graphene oxide (3D-GO) was decorated with Fe 3 O 4 to form nanocomposites of Fe 3 O 4 @3D-GO, which were further used as electrode materials in an electrochemical DNA sensor for detecting Ag + . Because of the chemical functionality and porous structure of the developed nanocomposites, single-stranded and cytosine-rich oligonucleotides could be anchored onto their surfaces or interior, followed by selective detection of Ag + through formation of C–Ag + –C complex forms. The results of electrochemical measurement showed that the Fe 3 O 4 @3D-GO nanocomposites exhibits high sensitivity for detecting Ag + with a detection limit of 2.0 pM within the range of 0.01–100 nM Ag + (S/N = 3). The developed electrochemical biosensor based on Fe 3 O 4 @3D-GO exhibits highly selectivity, good repeatability, and stability for detecting Ag + ions. The results of this work demonstrate that Fe 3 O 4 @3D-GO nanocomposites could be used as a promising tool to detect heavy metal ions in water or the environment.
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 29
·15299-15306
·
IF 7.443
Jugong Zheng,Cancan Qin,Tongfu Wu,Shuangfei Xie,Liang Ni,Muyang Peng,Yuefeng Tang,Yanfeng Chen
Preparing high-performance LiMnPO4 is still a large obstacle due to its sluggish electrochemical kinetics. To overcome this problem, a novel method is developed for LiMnPO4/C nanoplates from nanoporous Mn2O3 precursors. There are two advantages. Firstly, through negative pressure immersion, lithium dihydrogen phosphate (LiH2PO4), lithium hydroxide (LiOH) and sucrose (C12H22O11) are deposited on the surface of porous Mn2O3 nanosheets. In the following solid-state reaction, three dimensional continuous conductive carbon is wrapped uniformly around the LiMnPO4/C nanoplates, which greatly improved the conductivity. Secondly, (010) exposed facets are obtained using the Mn2O3 hierarchical microspheres as precursors, which allows for a fast transmission of Li+ ions improving the rate capability. As a result, the as-synthesized L-Mn2O3-LMP/C samples exhibit a superior rate performance with discharge capacities of 157.3 mA h g−1 at C/20, 122.6 mA h g−1 at 1C, and 105.8 mA h g−1 at 2C. Meanwhile, they can retain 99.3% of the initial capacity after 100 cycles at 1C, revealing an excellent cycling stability. This method sheds more light on the fabrication of high-performance LiMnPO4/C cathode materials and is suitable for large scale productions.
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）