JOURNAL OF SURFACTANTS AND DETERGENTS
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2017
·Vol. 20
·期 4
·873-880
·
IF 1.45
Zhao Mingwei,Wang Shilu,Dai Caili
Hydrophobic silica nanoparticles were prepared for pressure decreasing in water injection through modification of hydrophilic silica nanoparticles by n -propyltrichlorosilane. Fourier transform infrared spectroscopy analysis and surface hydroxyl number measurement results certified that the modification was very successful. The core flowing experiment showed that the modified hydrophobic silica nanoparticles have an excellent pressure-decreasing ability. The contact angles measurement results showed that the core chip changed from strong water wet to neutral wet after treated by the modified silica nanoparticles. In this work, a roughness decreasing mechanism is proposed to explain the pressure-decreasing mechanism of modified silica nanoparticles. After injection into the core, the modified silica nanoparticles occupied the spaces between the sand grains, forming a discontinuous hydrophobic film on the flowing channel surface. This can not only partially change the wettability of the sand surface, but also decrease the roughness of the core flowing channel, decreasing the critical layer thickness and flowing pressure accordingly.
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JOURNAL OF MOLECULAR STRUCTURE
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2016
·
IF 1.78
Tianyang Wang,Haiya Sun,Ting Lu,Krithanthi C. Weerasinghe,Dongzhi Liu,Wenping Hu,Xueqin Zhou,Lichang Wang,Wei Li,Lizeng Liu
It is proved that introducing the ethyl substituted group to 1-amino will enhance the intramolecular charge transfer ( ICT ) process of 1-N substituted anthraquinone derivatives. Bathochromic shift of the absorption maxima and diminished absorption intensity are observed with the increase of the electron donation abilities of the N-ethyl groups. Moreover, the intramolecular and intermolecular hydrogen bonds further intensify the ICT properties through introducing the end amino group. This work exhibits more effective acceptors than anthraquinone in novel multichromophore materials for organic solar cells and other optoelectronic devices.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2016
·
IF 3.014
Wei Xu,Tao Wang,Sanding Wu,Sheng Wang
Molybdenum disulfide (MoS 2 ) is a promising alternative anode material for lithium-ion batteries (LIBs). MoS 2 has unique layered crystal structure with a large and tunable interlayer distance, and is anticipated to have excellent rate and cycling stabilities due to improved lithium ion intercalation and de-intercalation. In this work, we successfully prepared novel N-doped carbon-coated MoS 2 nanosheets on hollow carbon microspheres . The composite spheres have an average diameter of 520 nm. We demonstrate that these electrodes show excellent electrochemical performance, which is attributed to the synergistic effect between the carbon microspheres, N-doped carbon coating, and MoS 2 nanosheets. The best performing electrode has high specific capacity of 997 mAh g −1 and good cycling stability, retaining a capacity of around 707 mAh g −1 at a current density of 100 mA g −1 after 120 cycles; furthermore, the electrode shows stable rate performance, retaining a capacity of 631 mAh g −1 at a current density of 2000 mA g −1 .
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Journal of Materials Chemistry A
·
2016
·Vol. 4
·期 29
·11357-11364
·
IF 8.262
Teng Liu,Pingping Zhao,Xing Hua,Wei Luo,Shengli Chen,Gongzhen Cheng
A simple Zn/Fe bimetallic zeolitic–imidazolite framework (ZIF) carbonization method is developed to synthesize an Fe–N–C hybrid with hierarchical nitrogen-doped porous carbons crossed by carbon nanotubes. Both the specific ratios of Zn/Fe in the bimetallic metal–organic framework (MOF) precursors and the selected annealing temperature are essential for the formation of this unique hybrid structure with good conductivity and exposure of more active sites. The resulting FeNC-20-1000 hybrid electrocatalyst exhibits excellent oxygen reduction reaction (ORR) activity, with a half-wave potential of 0.770 V comparable to that of the commercial Pt/C catalysts in acidic media, and a half-wave potential of 0.880 V, ca. 50 mV more positive than that of Pt/C for ORR in alkaline solution. More importantly, the as-prepared Fe–N–C hybrid exhibits much more stability for the ORR in both acidic and alkaline solutions than Pt/C, which makes it among the best non-noble-metal catalysts ever reported for ORR under acidic and alkaline conditions.
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CHEMOSPHERE
·
2017
·
IF 4.208
Xiaohua Ren,Huanhuan Guo,Jinkui Feng,Pengchao Si,Lin Zhang,Lijie Ci
3D porous N-doped reduced graphene oxide (N-rGO) aerogels were synthesized by a hydrothermal reduction of graphene oxide (GO) with urea and following freeze-drying process. N-rGO aerogels have a high BET surface of 499.70 m 2 /g and a high N doping content (5.93–7.46 at%) including three kinds of N (graphitic, pyridinic and pyrrolic). Their high catalytic performance for phenol oxidation in aqueous solution was investigated by catalytic activation of persulfate (PS). We have demonstrated that N-rGO aerogels are promising metal-free catalysts for phenol removal. Kinetics studies indicate that phenol degradation follows first-order reaction kinetics with the reaction rate constant of 0.16799 min −1 for N-rGO-A(1:30). Interestingly, the comparison of direct catalytic oxidation with adsorption-catalytic oxidation experiments indicates that adsorption plays an important role in the catalytic oxidation of phenol by decreasing the phenol degradation time. Spin density and adsorption modeling demonstrates that graphitic N in N-rGO plays the most important role for the catalytic performance by inducing high positive charge densities to adjacent carbon atoms and facilitating phenol adsorption on these carbon sites. Furthermore, the activation mechanism of persulfate (PS) on N-rGO was first investigated by DFT method and PS can be activated to generate strongly oxidative radical (SO 4 · - ) by transferring electrons to N-rGO.
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APPLIED CLAY SCIENCE
·
2016
·
IF 2.586
Shanshan Yang,Pingxiao Wu,Liya Chen,Ligui Li,Zhujian Huang,Shuai Liu,Liping Li
Montmorillonite (Mt), as an efficient adsorbent, has been widely applied in the treatment of wastewater. However, it is important to develop appropriate disposal methods, which are currently lacking for spent Mt after adsorption. We utilized Mt after adsorption of tetracyclines (TC) as carbon source to obtain a by-product, N-doped graphene-like carbon-based electrocatalysts (TC-C), by a facile and low cost pyrolysis strategy. Physicochemical and electrochemical characterization of TC-C indicated that the resultant TC-C was made up of many ultrathin nanosheets , which resembled the morphology of graphene, and it had a large Brunauer-Emmett-Teller surface area with narrow slit-like pores. Nitrogen doping was evaluated through X-ray photoelectro-spectra measurements and four nitrogen-bonding configurations were identified and quantified, including pyridinic N, pyrrolic N, graphitic N and pyridinic N + –O − . Electrochemical studies showed that TC-C exhibited high catalytic activity for the oxygen reduction reaction (ORR) in alkaline medium with outstanding methanol tolerance compared to the commercial Pt/C catalysts. Furthermore, the effect of the adsorbed amount of TC on the ORR activity of TC-C was slight and the pyrolysis temperature of 700 °C was demonstrated to be the optimal temperature for the pyrolysis process in the recycling of spent Mt.
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TALANTA
·
2016
·
IF 4.035
Wenjie Gao,Henghui Li,Yanyan Liu,Yuhong Liu,Xiaojun Feng,Bi-Feng Liu,Xin Liu
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has become an important technology for glycan analysis due to its ease of operation, short analysis time and impurity tolerance. However, the low ionization efficiency of N-glycans led to the difficulty in analyzing glycans of low abundance in complex biological samples due to the lack of basic site for protonation. Therefore, highly sensitive method for the glycans analysis is in urgent demand. Here we report a new strategy to introduce a permanent charge at the reducing end of N-linked glycans by a one pot reaction , where glycosylamines that were obtained by rapid deglycosylation within 5 min were labeled with N-succinimidyloxycarbonylmethyl tris (2,4,6- trimethoxyphenyl) phosphonium bromide (TMPP-Ac-OSu). With TMPP-Ac labeling, more than 50 fold enhancement in the sensitivity of method was achieved for neutral glycans from ribonuclease B (RNase B) in comparison to their native counterparts. In combination with methylamidation of sialic acid residues, this novel developed strategy could also be used for sialylated glycans analysis from sialoglycoproteins and complex serum sample. As a result, more than 50 glycans were detected with only 25 nL human serum sample.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2016
·
IF 3.014
Qian Feng,Dongyan Tang,Haitao Lv,Weile Zhang,Wenbo Li
We reported on the fabrication of thermo-responsive polymers of poly( N -isopropylacrylamide) (PNIPAM) graft ZnO by surface-initiated atom transfer radical polymerization (SI-ATRP) to contribute the characteristics of the grafted PNIPAM, meanwhile, without sacrificing the properties of ZnO. The structures of nanoparticles and the grafted polymer were confirmed by XRD and FT-IR and the interactions between the two components were studied by XPS . The morphology of ZnO NPs-PNIPAM nanocomposites was observed by SEM images and a thin layer of polymers (2 nm) formed around NPs was measured by TEM. EDS mapping images revealed the even distribution polymers on the surface of ZnO NPs. Based on the TG results, the grafting density of ATRP initiators at the surface of ZnO NPs was estimated to be 0.7 nm 2 /initiator. Furthermore, photodegradation of Rhodamine B (Rh-B) in the presence of nanocomposites revealed that ZnO NPs-PNIPAM exhibited photocatalysis , temperature-controlled switching and good recycling performance, indicating the significant potential applications in the practical applications.
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Science of Nature
·
2017
·Vol. 104
·期 7
·1-9
·
IF 1.191
Wang Congyan,Zhou Jiawei,Liu Jun,Jiang Kun
Differences in functional traits between invasive and native plant species are believed to determine the invasion success of the former. Increasing amounts of anthropogenic nitrogen (N) are continually deposited into natural ecosystems, which may change the relative occurrence of the different N deposition forms (such as NH 4 –N, NO 3 –N, and CO(NH 2 ) 2 –N) naturally deposited. Under high N deposition scenarios, some invasive species may grow faster, gaining advantage over native species. In a greenhouse experiment, we grew invasive and native Amaranthus species from seed both alone and in competition under simulated N enriched environments with different forms of N over 3 months. Then, we measured different leaf traits (i.e., plant height, leaf length, leaf width, leaf shape index, specific leaf area (SLA), and leaf chlorophyll and N concentrations). Results showed that the competition intensity between A. retroflexus and A. tricolor decreased under N deposition. This may be due to the large functional divergence between A. retroflexus and A. tricolor under simulated N deposition. Phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus were significantly lower than in A. tricolor . The lower range of phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus may indicate a fitness cost for plastic functional traits under adverse environments. The restricted phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus may also stabilize leaf construction costs and the growth rate. Meanwhile, the two Amaranthus species possessed greater plasticity in leaf N concentration under NO 3 –N fertilization, which enhanced their competitiveness.
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RSC Advances
·
2017
·Vol. 7
·期 22
·13325-13330
·
IF 3.108
Zhenlong Zhang,Junfeng Li,Xiaoli Wang,Jianqing Qin,Wenjia Shi,Yuefeng Liu,Huiping Gao,Yanli Mao
In this paper, Zr and N co-doped TiO2 (Zr/N–TiO2) nanorod arrays were synthesized using a hydrothermal method and perovskite solar cells were fabricated using them as an electron transfer layer. The solar cells based on Zr/N–TiO2 presented an enhanced performance compared with those based on un-doped TiO2. The solar cell performance was optimized by changing the Zr doping content. The efficiency of solar cells based on Zr/N–TiO2 with a Zr doping content of 1% (Zr/Ti, atomic ratio) has been achieved at 12.6%, which was 31.6% higher than that of solar cells based on un-doped TiO2. To get an insight into the enhancement, some investigations were carried out. The results indicate that the larger open voltage (Voc) could be due to the larger conduction band offset resulting from the smaller energy band gap for Zr/N–TiO2, and the enlarged short current (Isc) could be attributed to the faster electron transfer and reduced recombination rate for Zr/N–TiO2 NRs. These induce the enhancement of solar cell efficiency.
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Nanoscale
·
2017
·Vol. 9
·期 44
·17593-17600
·
IF 7.367
Min Wang,Xiangqian Fan,Lingxia Zhang,Jianjun Liu,Beizhou Wang,Ruolin Cheng,Mengli Li,Jianjian Tian,Jianlin Shi
Porous activated carbons (PACs) are promising candidates to capture CO2 through physical adsorption because of their chemical stability, easy-synthesis, cost-effectiveness and good recyclability. However, their low CO2 adsorption capacity, especially low CO2/N2 selectivity, has limited their practical applications. In this work, an optimized PAC with a large specific surface area, a small micropore size, and a large micropore volume has been synthesized by one-step carbonization/activation of casein using K2CO3 as a mild activation agent. It showed a remarkably enhanced CO2 adsorption capacity as high as 5.78 mmol g−1 and an excellent CO2/N2 selectivity of 144 (25 °C, 1 bar). Based on DFT calculations and experimental results, the coexistence of adjacent pyridinic N and –OH/–NH2 species was proposed for the first time to make an important contribution to the ultra-high CO2 adsorption performance, especially CO2/N2 selectivity. This work provides effective guidance to design PAC adsorbents with high CO2 adsorption performance. The content of pyridine N combined with –OH/–NH2 was further elevated by additional nitrogen introduction, resulting in a further enhanced CO2 adsorption capacity up to 5.96 mmol g−1 (25 °C, 1 bar). All these results suggest that, in addition to the well-defined pore structure, pyridinic N with neighboring OH or NH2 species played an important role in enhancing the CO2 adsorption performance of PACs, thus providing effective guidance for the rational design of CO2 adsorbents.
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BIOSENSORS & BIOELECTRONICS
·
2017
·
IF 7.78
Mai Luo,Yifan Hua,Yiran Liang,Jiajun Han,Donghui Liu,Wenting Zhao,Peng Wang
A novel functionalized carbon dot has been synthesized by covalently linking β-cyclodextrin to the surface of N, S codoped carbon dots (β-CD-CDs). The characterization was confirmed by transmission electron microscopy , X-ray photoelectron spectroscopy, infrared spectra, ultraviolet-visible, and fluorescence emission spectra. On the basis of this carbon dot and (ferrocenylmethyl) trimethylammonium iodide (Fc + ), a photo-induced electron transfer (PET) fluorescent probe system was developed to determine the concentration of testosterone in water and identify testosterone in cell by fluorescence imaging as a visible biomarker. Under the optimum condition, the fluorescent intensity of the probe system linearly responded to the concentration of testosterone from 0 μM to 280 μM and the limit of detection was 0.51 μM. This probe system also performed well at determining testosterone in groundwater with average recoveries of testosterone ranging from 96% to 107% at spiking levels of 0.5–100 μM, and the relative standard deviation remained below 13%, which provided a reliable, rapid and easy method to determine testosterone in environmental water. Furthermore, the low cytotoxicity, high anti-interference ability, and excellent biocompatibility of β-CD-CDs made this probe system successfully used in cell fluorescence imaging to monitor levels of testosterone in the cytoplasm of cells with a promising application value in medical research.
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