POLYMER
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2019
·
IF 3.771
Manoj B. Kale,Nidhin Divakaran,Suhail Mubarak,Duraisami Dhamodharan,T. Senthil,Lixin Wu
The in situ polymerization scheme was chose to introduce the amine intercalated α-zirconium phosphate (fZrP) in the waterborne polyurethane (WPU). The α-ZrP (ZrP) was prepared by refluxing zirconyl chloride octahydrate and then amine intercalated using ethylenediamine . The nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy , X-ray photoelectron spectroscopy and thermogravimetric analysis . The fZrP was introduced in the WPU with the known filler content of 0.1, 0.5 and 1 wt%, respectively. The prepared WPU/fZrP nanocomposites films have shown better mechanical, thermal and water resistance properties compared to the neat WPU and unmodified ZrP nanocomposites. The tensile strength of WPU filled with 1 wt% fZrP was increased by 57.09% against the WPU filled with 1 wt% unmodified ZrP. The thermal properties of the WPU showed increasing performance with the increasing fZrP content. The incorporation of fZrP in the WPU increased the thermal conductivity from 0.1777 W/m . K for virgin WPU and 0.2969 W/m . K for WPU/fZrP (1 wt%). The water resistance performance of the WPU was also improved with the increasing filler content. The results portray that the α-ZrP nanoplates can be an additive material to improve the thermo-mechanical performance of polymers.
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高影响因子
Polymers
·
2019
·Vol. 11
·期 9
·1417
·
IF 3.164
Wei Wang,Zufeng Xiao,Chaofan Huang,Kewang Zheng,Yin Luo,Yumin Dong,Zitong Shen,Wei Li,Caiqin Qin
Chitosan microspheres modified by 2-pyridinecarboxaldehyde were prepared and used in the construction of a heterogeneous catalyst loaded with nano-Cu prepared by a reduction reaction. The chemical structure of the catalyst was investigated by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS). Under mild conditions, such as no ligand at room temperature, the catalyst was successfully applied to catalyze the borylation of α,β-unsaturated receptors in a water-methanol medium, yielding 17%–100% of the corresponding β-hydroxy product. Even after repeated use five times, the catalyst still exhibited excellent catalytic activity.Keywords:chitosan microspheres;copper;organoboron compounds
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PubMed
高影响因子
POLYMER DEGRADATION AND STABILITY
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2019
·
IF 3.78
Yong Luo,Delong Xie,Yifan Chen,Tao Han,Renjie Chen,Xinxin Sheng,Yi Mei
To overcome the flammability and melt dripping issues of poly(vinyl alcohol) (PVA) aerogel , a combination of ammonium polyphosphate (APP) and α-zirconium phosphate (α-ZrP) was used to enhance the flame retardancy of PVA aerogels, which were fabricated using a simple mixing and freeze-drying approach. Results obtained from transmission electron microscopy (TEM) and atomic force microscopy (AFM) confirm that α-ZrP was successfully exfoliated by ultrasonic stripping. The effects of the exfoliated α-ZrP nano-plates on the microstructure, composition , flame retardancy, fire behavior of the aerogels was investigated using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), limiting oxygen index (LOI), UL-94 vertical burning, and cone calorimetry test. It was found that the incorporation of α-ZrP improved the 3D network structure of the PVA aerogel. The results showed that a sample with 2 wt% α-ZrP and 13 wt% APP could reach the maximal LOI value of 43.1%, achieved the UL-94 V-0 rating, and the peak heat release rate (PHRR) and total heat release (THR) of the sample reduced by 82.6% and 76.3%, respectively. Thermogravimetric analysis (TGA) revealed that α-ZrP improved the thermal stability of PVA-APP system. The residues analysis revealed that α-ZrP accelerated the formation of a compact and graphitization structure of residues and catalyzed the charring of PVA during burning.
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高影响因子
DALTON TRANSACTIONS
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2019
·Vol. 48
·期 44
·16626-16632
·
IF 4.052
Haonan Liu,Hongping Wu,Hongwei Yu,Zhanggui Hu,Yicheng Wu
New polymorphous phases, α- and β-LiMoPO6, have been successfully synthesized by the high temperature solution technique and their structures have been determined by single crystal X-ray diffraction. α-LiMoPO6 crystallizes in the orthorhombic space group Pbcn (No. 60) with a = 12.1141(4) Å, b = 8.9251(3) Å and c = 8.7389(3) Å, while β-LiMoPO6 crystallizes in the monoclinic space group P21/c (No. 14) with a = 6.3441(3) Å, b = 7.5949(3) Å, c = 9.3430(4) Å and β = 94.546(4)°. Both structures exhibit a similar three-dimensional (3D) framework composed of MoO6 octahedra and PO4 tetrahedra. Interestingly, an anomalous phase transition, i.e. the high-temperature β-LiMoPO6 phase exhibiting larger density than the low-temperature α-LiMoPO6, has been observed. Detailed structural analyses show that the anomalous phase transition mainly originates from the ‘straightened’ effect of the zigzag [MoO3O3PO]∞ chains in their structures. Furthermore, the optical and thermal properties of two compounds are also reported.
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2019
·
IF 6.393
Xin Cheng,Yan Huang,Diying Li,Chao Yuan,Zi-Long Li,Linhao Sun,Hong Jiang,Jimei Ma
α- l -Fucosidase (AFu) is an important biomarker for early diagnosis of hepatocellular carcinoma and fucosidosis. In this study, a novel, sensitive and selective polymer dots (PDs) fluorescent sensing strategy based on inner filter effect was firstly developed for AFu activity determination. The PDs with a high quantum yield of 53.6% were synthesized by a mild one-pot method. The detection mechanism of this strategy was based on inner filter effect between PDs and p-nitrophenol (PNP) which was the hydrolyzate of 4-nitrophenyl-α- l -fucopyranoside (PNPF) catalyzed by AFu. The absorption of PNP overlapped the fluorescence excitation spectrum of the PDs, which resulted in a fluorescence quenching or weakening of PDs. The sensing system showed a good linear relationship within 0.01-0.9 U L −1 and provided a low AFu detection limit of 0.001 U L −1 (S/N = 3). This PDs sensor were successfully applied for the determination of AFu in human serum samples.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
Wenxiu He,Hengrui Qiu,Jing Meng,Bin Liu,Jinlong Cui,Yongqiang Zhang
A nanoscale petal-like α-Ni(OH) 2 /reduced graphene oxide (α-Ni(OH) 2 /RGO) composite was synthesized with the one-step microwave method. α-Ni(OH) 2 particles with sizes of approximately 200 nm are uniformly distributed on the reduced graphene oxide sheet in the sample. When used as an electrode for alkaline rechargeable batteries, the discharge capacity of the α-Ni(OH) 2 /RGO composite reaches 333.5 mAh/g at 0.2C and 247.1 mAh/g at 10 C, respectively, with an excellent rate capability. After 2000 cycles, the capacity of the electrode is insignificantly attenuated, indicating a high capacity retention and cycling stability. The outstanding electrochemical properties are attributed to the nanoscale petal-like structure α-Ni(OH) 2 anchoring on the RGO sheets, which facilitates ion diffusion and increases the active surface, which is effectively reacting with the electrolyte. The nanoscale petal-like electrode material fabricated in this study provides clues to address the problem of energy applications of high-performance alkaline rechargeable batteries.
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高影响因子
CELLULOSE
·
2019
·Vol. 26
·期 13
·8059-8071
·
IF 3.917
Xie Congxia,Qu Li,Yu Hailong,Yu Fengli,Yuan Bing,Yu Shitao,Nie Shuangxi
Abstract Ruthenium (Ru) nanoparticles synthesized using hydroxyethyl cellulose (HEC-Ru) were used to hydrogenate α-pinene in an aqueous medium. The results showed that HEC had a good dispersion effect on Ru nanoparticles and most of the particle sizes were ranged from 4 to 6 nm. The micelles formed with HEC appeared to act as “microreactors” in which the Ru nanoparticles had good stability and uniform distribution. In addition, α-pinene was loaded into the HEC micelles through hydrophobic interaction, resulting in good contact with Ru nanoparticles. Thereby, HEC-Ru nanoparticles significantly improved the hydrogenation of α-pinene, and 99.6% of α-pinene conversion and 98.6% of cis-pinane selectivity were obtained. Compared with the Pd/C, Ru/H 2 O, and HEC-Ru/ethanol catalyst systems, the HEC-Ru/H 2 O system had the maximum α-pinene conversion. In addition, considerable α-pinene conversion could be obtained after 10 times reuse with no fresh addition. Graphic abstract
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高影响因子
Molecular Catalysis
·
2019
·
IF 2.938
Zhijie Wang,Anxiang Guan,Mayfair C. Kung,Anyang Peng,Harold H. Kung,Ximeng Lv,Gengfeng Zheng,Linping Qian
Aerobic oxidation of α-C H bond of organic compounds to valuable chemicals is widely investigated in both fundamental research and industry. Due to the good stability of molecular oxygen, severe reaction conditions are generally required. Herein, by in situ synthesis we used molecular oxygen to induce cobalt nanoclusters with the sensitive catalysis in mild selective oxidation. The cobalt containing clusters with an average diameter around 0.9 nm are in situ prepared in the presence of cis -cyclooctene epoxidation and cyclooctene dimer oxide is formed at the interface to stabilize Co clusters with electron donation as an oil-soluble surfactant. The soluble clusters exhibit high activity in selective oxidation of α-C H bond of ethylbenzene into acetophenone and turnover number (TON) reaches about 7 × 10 4 during 50 h’ reaction at 373 K, which is around 960 times more active than the one using CoCl 2 salt as the catalyst, resulting from efficient mass transportation, π bond interaction and oxygen gas activation. Extended work based on this understanding demonstrates that cobalt nanoclusters also effectively catalyze aerobic oxidation of cyclohexene.
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高影响因子
MATERIALS CHEMISTRY AND PHYSICS
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2019
·
IF 2.781
Jirong Bai,Haiyang Xu,Gang Chen,Wenhua Lv,Zhijiang Ni,Zhilei Wang,Jiaying Yang,Hengfei Qin,Zheng Zheng,Xi Li
α-Fe 2 O 3 /porous g-C 3 N 4 (α-Fe 2 O 3 /PCN) photocatalysts were fabricated via a facile and green method. Structural characterization indicated α-Fe 2 O 3 nanoparticles were successfully loaded onto PCN. The α-Fe 2 O 3 /PCN nanocomposites were proven durable with significantly enhanced photocatalytic activity for Rhodamine B photodegradation than the single components under visible light irradiation. The improved photoactivity was mainly attributed to the broadened visible light absorption, enriched active sites, and formation of α-Fe 2 O 3 /PCN heterojunction that addressed the recombination of photoinduced electrons and holes. The α-Fe 2 O 3 /PCN hybrids also showed high recyclability and chemical stability.
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高影响因子
NANOTECHNOLOGY
·
2019
·Vol. 31
·期 10
·105707
·
IF 3.399
Zijian Chen,Ting Guo,Zhuangzhi Wu,Dezhi Wang
As highly efficient non-precious metal-based catalysts for the hydrogen evolution reaction (HER), molybdenum carbides have attracted much attention over the phase and structure modification for the improvement of HER performances. In this work, a novel strategy is proposed to modulate phases of molybdenum carbides by boron doping, so that the HER performances can be well controlled. After B-doping, the HER activity of the as-prepared B30 catalyst is significantly enhanced with a much smaller Tafel slope of 78 mV dec−1 than that of the blank one (134 mV dec−1), which originates from the increased amount of active sites, enhanced turnover frequency of each active site and reduced electron transfer resistance. Moreover, this work could broaden our view of phase regulation and provide more possible perspectives for the application in other fields.
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高影响因子
CHEMISTRY AND ECOLOGY
·
2018
·
IF 1.091
Tingfeng Liu,Keqiang Ding,Guang Guo,Feng Yang,Lihong Wang
Effect of hydroxypropyl-β-cyclodextrin (HPCD) on the bioavailability and biodegradation of the polycyclic aromatic hydrocarbons (PAHs) pyrene (PYR) and benzo[α]pyrene (BaP) in spiked soils was investigated in 14-week incubation experiments. To evaluate the effect of HPCD in soils with a different matrix, humic substance (HS) was added into soil samples. A 6-h Tenax TA extraction method was used to evaluate pollutants bioavailability. The biodegraded and extracted fractions were compared to evaluate the impact of HPCD on PAHs biodegradation. Results indicated positive effects of HPCD on fast desorption behaviours of PAHs. The biodegraded fraction was consistent with that of the extracted for PYR. However, in terms of BaP, the results were contrary which suggests that biological factors may be limiting factors for BaP pollution remediation. HS weakened the HPCD solubilisation effect while accelerated the decay of PYR and BaP, also implying that bioavailability was not the sole factor limiting PAH biodegradation. In addition, analysis of microbial communities demonstrated that HPCD inhibited the growth of some soil bacteria while HS promoted the evolution of some soil microorganisms. A limited population of hydrocarbon degrader populations led to observing incomplete PAH biodegradation even in the presence of HPCD.
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高影响因子
ACS Catalysis
·
2018
·
IF 11.384
Yizhou Wu,Jesse Ward-Bond,Donglin Li,Shaohua Zhang,Jiafu Shi,Zhongyi Jiang
Graphitic carbon nitride (g-C3N4) is an emergent metal-free photocatalyst because of its band position, natural abundance, and facile preparation. Synergetic intensification of charge generation and charge transfer of g-C3N4 to increase solar-to-chemical efficiency remains a hot yet challenging issue. Herein, a nanoshell with two moieties of α-Fe2O3 and carbon (C) is in situ formed on the surface of a g-C3N4 core through calcination of Fe3+/polyphenol-coated melamine, thus acquiring g-C3N4@α-Fe2O3/C core@shell photocatalysts. The α-Fe2O3 moiety acts as an additional photosensitizer, offering more photogenerated electrons, whereas the C moiety bridges a “highway” to facilitate the electron transfer either from α-Fe2O3 moiety to g-C3N4 or from g-C3N4 to C moiety. By tuning the proportion of these two moieties in the nanoshell, a photocurrent density of 3.26 times higher than pristine g-C3N4 is obtained. When utilized for photocatalytic regeneration of reduced nicotinamide adenine dinucleotide (NADH, a dominant cofactor in biohydrogenation reaction), g-C3N4@α-Fe2O3/C exhibits an equilibrium NADH yield of 76.3% with an initial reaction rate (r) of 7.7 mmol h–1 g–1, among the highest r for photocatalytic NADH regeneration ever reported. Manipulating the coupling between charge generation and charge transfer may offer a facile, generic strategy to improve the catalytic efficiency of a broad range of photocatalysts other than g-C3N4.
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