CATALYSIS LETTERS
·
2013
·Vol. 143
·期 9
·873-880
·
IF 2.244
Yang Lan,Luo Wei,Cheng Gong-Zhen
Abstract Amorphous nickel catalysts derived from nickel halides (NiF 2 , NiCl 2 , NiBr 2 , NiI 2 ) were in situ synthesized in an aqueous solution of NaBH 4 /NH 3 BH 3 . The halide anions have effects on the formation of Ni(0) catalysts, which can further affect the catalytic activities and activation energies of the catalysts for the hydrolysis of ammonia borane. The PVP stabilized catalysts have higher hydrogen evolution rates and durabilities than bare Ni catalysts for the hydrolysis of ammonia borane. The catalysts derived from NiBr 2 stabilized by PVP present the highest catalytic activity and the lowest activation energy, which has been measured to be 25.58 kJ/mol. This value is lower than most of reported Ni-based catalysts and even noble-metal containing catalysts. The results of mercury poisoning experiment reveal that Ni(0) catalysts derived from NiBr 2 are heterogeneous catalysts in the hydrolysis of ammonia borane. Graphical Abstract
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Plasmonics
·
2015
·Vol. 11
·期 3
·771-779
·
IF 2.238
Zhang Pengfei,Liu Le,He Yonghong,Ji Yanhong,Guo Jun,Ma Hui
We describe a temperature-regulated surface plasmon resonance (SPR) imaging biosensor in this article. The sample temperature can be regulated for specific requirements of the bioaffinity sensing, and stabilized to suppress the measurement noise caused by temperature fluctuations. The water thermo optic coefficient is measured to test the temperature regulation performance. The protein interaction is monitored to demonstrate the feasibility of this system for real-time biomolecular interaction analysis. This temperature-regulated SPR imaging biosensor can be readily implemented by adding the common water path and peristaltic pump to the conventional SPR imaging system, which may provide an economical and convenient scheme to improve the analysis accuracy and quality of bioaffinity sensing using SPR sensing platform.
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JOURNAL OF APPLIED ELECTROCHEMISTRY
·
2015
·Vol. 46
·期 1
·1-8
·
IF 2.409
Liang Xiaocai,Xiao Mingshu,Xu Minglu,Yang Dazhang,Yan Yuhua,Tian Yanping,Miao Yuqing
This study investigated the simultaneous in situ formation of Ni-based catalysts at the anode and cathode for glycerol oxidation and hydrogen evolution, respectively. The formation of electrocatalysts and their immobilization on the electrode surface occur simultaneously, avoiding the tedious and laborious procedures for the preparation and immobilization of the electrocatalysts. Ni salt in the homogeneous solution was deposited to repair the Ni-based electrocatalysts on the electrode surface, accompanied by the electrolysis of glycerol at the anode and the hydrogen evolution reaction at the cathode, exhibiting good working stability. This technique may find potential applications in the conversion of solar energy into storable fuels via the electrolysis of H 2 O or small molecules to produce hydrogen.
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JOURNAL OF MATERIALS SCIENCE
·
2015
·Vol. 50
·期 18
·6113-6123
·
IF 2.371
Liu Xiaoyan,Zhou Yifeng,Nie Wangyan,Song Linyong,Chen Pengpeng
Novel environmental friendly hydroxypropyl cellulose (HPC) hydrogels were fabricated upon compositing with graphene oxide (GO) in this work. In order to promote a more homogeneous dispersion of GO sheets in HPC, GO was firstly modified with HPC chains through esterification. The morphology and chemical structure of the functionalized HPC-GO were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectrometer, X-ray diffraction, and thermo-gravimetric analysis. Then scanning electronic microscope was employed to compare the morphologies of the HPC and HPC-GO/HPC hydrogels. The obtained HPC-GO/HPC hydrogels exhibited excellent adsorption performance toward methylene blue. Simulation of the practical use by preparing simple adsorption columns made from in situ formation of HPC-based hydrogels had given a visible observation of the significant adsorption effect brought by the incorporation of HPC-GO sheets. Adsorption kinetics were then imitated by Lagergren pseudo-first-order and pseudo-second-order models. Adsorption isotherms were imitated by Langmuir isotherm and Freundlich isotherm.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2015
·Vol. 33
·期 12
·1713-1720
·
IF 1.835
Shao Jun,Liu Yan-long,Xiang Sheng,Bian Xin-chao,Sun Jing-ru,Li Gao,Chen Xue-si,Hou Hao-qing
In this study, the poly(L-lactide)/poly(D-lactide) (PLLA/PDLA) blends with different optical purities of PLLA and various molecular weights of PDLA are prepared by solution mixing, and the stereocomplex formation and phase separation behaviors of these blends are investigated. Results reveal that optical purity and molecular weight do not vary the crystal structure of PLA stereocomplex (sc) and homochiral crystallites (hc). As the optical purity increasing in the blends, the melting temperature of sc ( T
sc ) and the content of sc (Δ H
sc ) increased, while the melting temperature of hc ( T
hm ) hardly changes, although the content of hc (Δ H
hm ) decreased gradually. The T
sc and Δ H
sc are also enhanced as the molecular weight of PDLA reduces, and the Δ H
hm reduces rapidly even though the T
hm does not vary apparently. With lower optical purities of PLLA and higher molecular weights of PDLA, three types of crystals form in the blends, i.e. , PLA sc, PLLA hc and PDLA hc. As molecular weight decreases and optical purity enhances, the crystal phase decreases to two (sc and PDLA hc), and one (sc) finally. This investigation indicates that the phase separation behavior between PLLA and PDLA in the PLLA/PDLA blends not only depends on molecular weights, but also relies on the optical purities of polymers.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2015
·Vol. 26
·期 10
·7914-7920
·
IF 1.569
Lan Zhang,Liu Lu,Huang Miaoliang,Wu Jihuai,Lin Jianming
Two kinds of hierarchical SnO 2 particles as nano-flower-like SnO 2 particles (NF-SnO 2 ) and mesoporous-sphere-like SnO 2 particles (MS-SnO 2 ) have been synthesized and used in CdS quantum dots (QDs) sensitized solar cells (QDSSC). TEM images show that NF-SnO 2 particles compose well interconnected nanoplates and MS-SnO 2 spheres are consisted with large numbers of SnO 2 nanoparticles with size about 7 nm. Owing to the larger Brunauer–Emmett–Teller surface area of NF-SnO 2 particles, NF-SnO 2 photoelectrode can load higher amounts of CdS QDs and shows enhanced light absorbance, resulting in higher short-circuit current density compared with that of MS-SnO 2 photoelectrode. The electrochemical impedance spectroscopy analysis results show that the QDSSC with NF-SnO 2 photoelectrode has a higher charge recombination resistance and a longer electron lifetime, so its photovoltaic performance is better than that of the QDSSC with MS-SnO 2 photoelectrode. The QDSSC with NF-SnO 2 photoelectrode can attain 3 % power conversion efficiency, which is higher than that of the cell with MS-SnO 2 photoelectrode (1.97 %).
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JOURNAL OF POROUS MATERIALS
·
2015
·Vol. 22
·期 5
·1357-1362
·
IF 1.108
Yin Liuyan,Zhou Xingui,Yu Jinshan,Wang Honglei
A planetary ball-milling foaming route was employed by the protein foaming method for preparing silicon nitride (Si 3 N 4 ) foams. In comparison with the commonly used tumbling foaming route of protein foaming method, pores of the Si 3 N 4 foams fabricated by this new foaming route are more uniform in size distribution and the pores pack more compact. Furthermore, effects of the rotating speed on the structure and the property of the Si 3 N 4 foams fabricated by this new foaming route were investigated. It was indicated that the average pore size decreased with the rotating speed, whereas the count of windows on the walls increased with the rotating speed. Moreover, the windows were found to have a negative influence on the phase transformation of Si 3 N 4 from α phase to β phase.
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JOURNAL OF NANOPARTICLE RESEARCH
·
2015
·Vol. 17
·期 4
·1-11
·
IF 2.184
Zhang Ruichang,Zhang Haibo,Tu Chen,Hu Xuefeng,Li Lianzhen,Luo Yongming,Christie Peter
The transport behavior of titanium dioxide nanoparticles (TiO 2 NPs, 30 nm in diameter) was studied in well-defined porous media composed of clean quartz sand over a range of solution chemistry under acidic conditions. Transport of TiO 2 NPs was dramatically enhanced by humic substances (HS) at acidic pH (4.0, 5.0 and 6.0), even at a low HS concentration of 0.5 mg L −1 . Facilitated transport of TiO 2 NPs was likely attributable to the increased stability of TiO 2 NPs and repulsive interaction between TiO 2 NPs and quartz sands due to the adsorbed HS. The mobility of TiO 2 NPs was also increased with increasing pH from 4.0 to 6.0. Although transport of TiO 2 NPs was insensitive to low ionic strength, it was significantly inhibited by high concentrations of NaCl and CaCl 2 . In addition, calculated Derjaguin–Landau–Verwey–Overbeek (DLVO) interaction energy indicated that high energy barriers were responsible for the high mobility of TiO 2 NPs, while the secondary energy minimum could play an important role in the retention of TiO 2 NPs at 100 mmol L −1 NaCl. Straining and gravitational settlement of larger TiO 2 NPs aggregates at 1 mg L −1 HS, pH 5.0, and 2 mmol L −1 CaCl 2 could be responsible for the significant retention even in the presence of high energy barriers. Moreover, more favorable interaction between approaching TiO 2 NPs and TiO 2 NPs that had been already deposited on the collector resulted in a ripening-shape breakthrough curve at 2 mmol L −1 CaCl 2 . Overall, a combination of mechanisms including DLVO-type force, straining, and physical filtration was involved in the retention of TiO 2 NPs over the range of solution chemistry examined in this study.
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JOURNAL OF MATERIALS SCIENCE
·
2014
·Vol. 50
·期 5
·2158-2166
·
IF 2.305
Ma Yanli,He Ling,Pan Aizhao,Zhao Chengben
The novel latex of P(GMA-POSS)- co -PMMA is synthesized for coatings by glycidyl methacrylate polyhedral oligomeric silsesquioxane (GMA-POSS) and methyl methacrylate (MMA). First, GMA-POSS is prepared by the epoxide opening reaction of glycidyl methacrylate (GMA) and aminopropyllsobutyl POSS (NH 2 -POSS). Then, the as-obtained GMA-POSS monomer is directly used for emulsion polymerization with MMA to obtain P(GMA-POSS)- co -PMMA latex. The chemical structure of P(GMA-POSS)- co -PMMA latex is characterized. The core–shell morphology of latex is proved to distribute uniform spherical particles as 20–60 nm in diameter. The effect of POSS content on the properties of film casting from P(GMA-POSS)- co -PMMA latex is studied for surface roughness, static contact angle, thermostability, and universal mechanical testing. The introducing of POSS into latex leads to an increase of P(GMA-POSS)- co -PMMA in the hydrophobicity, adhesive strength, thermal and mechanical proprieties. When GMA-POSS amount is controlled at 33 wt%, the glass transition temperature ( T
g ) and static contact angle are increased into 130 °C and 102º, respectively, and the adhesion to the substrate is raised to 477.2 MPa. Therefore, P(GMA-POSS)- co -PMMA is promising to be suggested as coating material.
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POLYMER BULLETIN
·
2016
·Vol. 73
·期 7
·2073-2085
·
IF 1.371
Zhang Xuzhen,Ma Piming,Zhang Yong
Cellulose nanocrystal (CNC) was extracted from microcrystalline cellulose (MCC) and then surface modified by acetic anhydride to obtain acetylated CNC (ACNC). ACNC that has lower polarity than CNC was mixed with poly(butylene adipate- co -terephthalate) (PBAT) through melt blending to obtain composites. ACNC was uniformly dispersed in PBAT matrix as evidenced by scanning electron microscopy observation. Thermogravimetric analysis indicates the thermal stability of PBAT could be improved by the addition of either CNC or ACNC. In the rheological tests and dynamic mechanical analysis, PBAT/ACNC composites showed higher melt elasticity, complex viscosity, storage modulus and glass transition temperature than PBAT/CNC composites, indicating a stronger interfacial adhesion between ACNC and PBAT. As a result of the uniform dispersion of ACNC and strong interfacial adhesion between ACNC and PBAT, mechanical properties of PBAT/ACNC composites improve obviously. Good mechanical properties, high initial decomposition temperature and high glass transition temperature of PBAT/ACNC composites could contribute to the practical commercial utilization of PBAT.
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MICROCHIMICA ACTA
·
2015
·Vol. 183
·期 2
·813-820
·
IF 3.741
Ling Xu,Zhang Wenpeng,Chen Zilin
The authors show that carbon fiber bundles electrochemically modified with the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is a viable sorbent for online solid-phase microextraction (SPME) of the sulfonamides (sulfadiazine, sulfadimidine and sulfamethoxazole) prior to their determination by HPLC. The fibers were packed in a tube loop made from polyether ether ketone (PEEK) that was coupled to the HPLC system for online SPME. Preconcentration factors can reach values of up to 300, and the limit of detection (at an S/N ration of 3) can be as low as 0.05 ng⋅mL −1 . The method was applied to the analysis of the sulfonamides in spiked rat plasma with intra-day and inter-day RSDs of <3.33 and <4.57 %, and with recoveries in the range from 91.7 to 97.8 % in spiked plasma. The in-tube SPME was also applied to the determination of the 3 sulfonamides in rat plasma after oral administration (tablet powder) with high sensitivity. In addition to its efficient extraction, the PEEK tube based SPME has chemical and mechanical stability under even harsh conditions.
Electrochemically modified carbon fibers were packed into polyether ether ketone (PEEK) tube and connect with HPLC system. Good stability and extraction efficiency over 300 fold have been obtained. Application in plasma samples exhibits high extraction efficiency, good reproducibility and recoveries.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2015
·Vol. 408
·期 4
·1231-1236
·
IF 3.436
He Yi,Wang Zeru,Long Dengying
The increasing application of nanomaterials will inevitably lead to their release into the environment, which may pose a threat to the environment and human health. As such, there is an urgent need to detect various nanomaterials. In the present work, we present a novel, rapid, and simple visual detection of MnO 2 nanosheets in buffer solution and environmental water sample. In this assay, a redox reaction between MnO 2 nanosheets and 3,3′,5,5′-tetramethylbenzidine (TMB) occurred, leading to the oxidation of TMB to TMB diimine. This redox reaction generated different colors dependent on the concentration of MnO 2 nanosheets, including colorless, blue, green, and yellow, which allowed semiquantitative detection of MnO 2 nanosheets with the naked eye. The detection range of the visual assay was 2–15 μg/mL, and the minimum concentration of MnO 2 nanosheets can be visually detected at concentrations down to 2.0 μg/mL. Moreover, the developed visual assay showed a high selectivity to MnO 2 nanosheets over Mn 2+ ions, tetramethylammonium hydroxide, hydrogen peroxide, graphene oxide, and graphitic carbon nitride nanosheets.
Visual detection of MnO 2 nanosheets
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