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Xiudan Hou, Xiaofeng Lu, Sheng Tang, Licheng Wang, Yong Guo
An environmental friendly sorbent of polymeric ionic liquids modified graphene oxide-grafted silica (PILs@GO@Sil) was synthesized for solid-phase extraction (SPE) of phenolic acids. The sorbent was prepared via a chemical layer-to-layer fabrication including amidation reaction, surface radical chain-transfer polymerization and in situ anion exchange. After modification with PILs, the silica surface had higher positive potential so that it would exhibit stronger electrostatic interaction for acidic compounds compared with GO@Sil...
November 12, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Hamid Kooshki, Jamal Rashidiani, Mehdi Kamali, Hamid Sedighian, Mostafa Akbariqomi, Mansour Mansouri
The increasing progress in using nano-biomaterials for medical purposes has opened new horizons toward researchers around the globe. To investigate the presence of these nanomaterials and the impacts they might have, a comparative enhanced-electrochemiluminescence immunosensing study has been designed. The effects of utilizing graphene oxide, silica, and gold nanoparticles in cancer diagnosis were evaluated during the quantification of two major cancer biomarkers (CEA and AFP) in different approaches. In other words, first and second approaches were designed to employ nanomaterials while third and fourth approaches were developed in absence of those...
November 8, 2017: Biosensors & Bioelectronics
Tao Meng, Fenyun Yi, Honghong Cheng, Junnan Hao, Dong Shu, Shixu Zhao, Chun He, Xiaona Song, Fan Zhang
Using ammonium chloride (NH4Cl) as the pore-forming agent, three-dimensional (3D) "fishnet-like" lithium titanate/reduced graphene oxide (LTO/G) composites with hierarchical porous structure are prepared via a gas-foaming method. SEM and TEM images show that in the composite prepared with the NH4Cl concentration of 1 mg mL-1 (1-LTO/G), LTO particles with sizes of 50~100 nm disperse homogeneously on the 3D "fishnet-like" graphene sheets. The nitrogen-sorption analyses reveal the existence of micro/mesopores, which is attributed to the introduction of NH4Cl into the gap between the graphene sheets that further decomposes into gases and produces hierarchical pores during the thermal treatment process...
November 17, 2017: ACS Applied Materials & Interfaces
Yun Liu, Wei Hao, Huiying Yao, Shuzhou Li, Yuchen Wu, Jia Zhu, Lei Jiang
Semiconducting polymers with π-conjugated electronic structures have potential application in the large-scale printable fabrication of high-performance electronic and optoelectronic devices. However, owing to their poor environmental stability and high-cost synthesis, polymer semiconductors possess limited device implementation. Here, an approach for constructing a π-conjugated polymer/graphene composite material to circumvent these limitations is provided, and then this material is patterned into 1D arrays...
November 17, 2017: Advanced Materials
Jingwen Ma, Min Wang, Guangyu Lei, Guoliang Zhang, Fengbao Zhang, Wenchao Peng, Xiaobin Fan, Yang Li
The development of highly efficient and durable non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) is significant for clean and renewable energy research. This work reports the synthesis of N-doped graphene nanosheets supported N-doped carbon coated cobalt phosphide (CoP) nanoparticles via a pyrolysis and a subsequent phosphating process by using polyaniline. The obtained electrocatalyst exhibits excellent electrochemical activity for HER with a small overpotential of -135 mV at 10 mA cm(-2) and a low Tafel slope of 59...
November 17, 2017: Small
Tao Hengcong, Jingjing Ding, Chao Xie, Yunnan Gao, Jinliang Song, Zhenyu Sun
We demonstrate a facile and versatile method to grow Ru particles uniformly on pristine few-layer graphene (FLG) in supercritical diethylamine. In particular, a large number of Ru subnanometer clusters less than 1.0 nm were observed. The particle size can be tuned by manipulating the loading content of Ru and controlling the reaction temperature. The resulting Ru/FLG showed remarkably high activity, selectivity, and reusability towards the hydrogenation of levulinic acid to γ-valerolactone. This method is flexible, and can be extended to the synthesis of a variety of other ultrafine metal particles supported on FLG...
November 17, 2017: Nanotechnology
Luca Gragnaniello, Fabian Paschke, Philipp Erler, Peter Schmitt, Nicole Barth, Sabina Simon, Harald Brune, Stefano Rusponi, Mikhail Fonin
We demonstrate that electrospray deposition enables the fabrication of highly periodic self-assembled arrays of Fe4H single molecule magnets on graphene/Ir(111). The energetic positions of molecular states are probed by means of scanning tunneling spectroscopy, showing pronounced long- and short-ranged spatial modulations, indicating the presence of both locally varying intermolecular as well as adsorption-site dependent molecule-substrate interactions. From the magnetic field dependence of the X-ray magnetic circular dichroism signal, we infer that the magnetic easy axis of each Fe4H molecule is oriented perpendicular to the sample surface and that after the deposition the value of the uniaxial anisotropy is identical to the one in bulk...
November 17, 2017: Nano Letters
Slavomir Nemšák, Evgheni Strelcov, Tomáš Duchoň, Hongxuan Guo, Johanna Hackl, Alexander Yulaev, Ivan Vlassiouk, David N Mueller, Claus M Schneider, Andrei Kolmakov
Studies of the electrified solid-liquid interfaces are crucial for the understanding of the biological and electrochemical systems. Until recently, the use of photoemission electron microscopy (PEEM) for such purposes has been hampered by the incompatibility of the liquid samples with ultra-high vacuum environment of the electron optics and detector. Here we demonstrate that the use of ultra-thin electron transparent graphene membranes, which can sustain large pressure differentials and act as a working electrode, makes it possible to probe electrochemical reactions in operando in liquid environments with PEEM...
November 17, 2017: Journal of the American Chemical Society
Tengfei Zhou, Guo Li, Shiyu Lin, Taoran Tian, Quanquan Ma, Qi Zhang, Sirong Shi, Changyue Xue, Wenjuan Ma, Xiaoxiao Cai, Yunfeng Lin
Bone tissue engineering emerges as an advantageous technique to achieve tissue regeneration. Scaffolds for it must present excellent biomechanical properties where bare polymers poorly perform. Development for new biomaterials with high osteogenic capacity is urgently pursued. In this study, an electrospun poly(3-hydroxybutyrate-co-4-hydroxybutyrate/graphene oxide (P34HB/GO) nanofibrous scaffold is successfully fabricated and characterized. The effects of GO amount on scaffold morphology, biomechanical properties, and cellular behaviors are investigated...
November 17, 2017: ACS Applied Materials & Interfaces
Zhu-Yin Sui, Pei-Ying Zhang, Meng-Ying Xu, Yuwen Liu, Zhi-Xiang Wei, Bao-Hang Han
Metal-organic frameworks (MOFs) are hybrid inorganic-organic materials that can be used as effective precursors to prepare various functional nanomaterials for energy-related applications. Nevertheless, most MOF-derived metal oxides exhibit low electrical conductivity and mechanical strain. These characteristics limit their electrochemical performance and hamper their practical application. Herein, we report a rational strategy for enhancing the lithium storage performance of MOF-derived metal oxide. The hierarchically porous Co3O4@NGN is successfully prepared by embedding ZIF-67-derived Co3O4 particles in a nitrogen-doped graphene network (NGN)...
November 17, 2017: ACS Applied Materials & Interfaces
Weixing Song, Jianxiong Zhu, Baoheng Gan, Shuyu Zhao, Hui Wang, Congju Li, Jie Wang
The graphene with 3D porous network structure is directly laser-induced on polyimide sheets at room temperature in ambient environment by an inexpensive and one-step method, then transferred to silicon rubber substrate to obtain highly stretchable, transparent, and flexible electrode of the all-solid-state planar microsupercapacitors. The electrochemical capacitance properties of the graphene electrodes are further enhanced by nitrogen doping and with conductive poly(3,4-ethylenedioxythiophene) coating. With excellent flexibility, stretchability, and capacitance properties, the planar microsupercapacitors present a great potential in fashionable and comfortable designs for wearable electronics...
November 17, 2017: Small
Sarita Yadav, Neetu Goel, Vinod Kumar, Kulbhushan Tikoo, Sonal Singhal
The environmental risks of antibiotics have attracted increasing research attention due to their prevalence and persistence in the aquatic environment. In this study, oxygen functionalized graphene, namely, graphene oxide (GO), was synthesized by modified Hummer's and Offeman's method and used as potential effective absorbent for the removal of fluoroquinolones (FQs), i.e., ciprofloxacin (CIP), norfloxacin (NOR), and ofloxacin (OFL), from aqueous solution. The as-synthesized GO was characterized by Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), and high-resolution transmission electron microscopy (HRTEM)...
November 16, 2017: Environmental Science and Pollution Research International
Eulogio J Llorent-Martínez, Gema M Durán, Ángel Ríos, Antonio Ruiz-Medina
We propose an alternative approach for the development of analytical methods based on terbium-sensitized luminescence (TSL). TSL is based on the complexation between Tb(III) ions and fluorescent organic compounds that have appropriate functional groups to complex with Tb(III). We report the use of graphene quantum dot (GQDs) nanoparticles to improve the sensitivity and selectivity of TSL detection. GQDs can react with terbium ions through the carboxylic groups present in their structure. These Tb(III)-GQD complexes, formed in situ in aqueous solution, can be used as time-resolved luminescent probes...
November 16, 2017: Analytical and Bioanalytical Chemistry
Jinsung Kwak, Yongsu Jo, Soon-Dong Park, Na Yeon Kim, Se-Yang Kim, Hyung-Joon Shin, Zonghoon Lee, Sung Youb Kim, Soon-Yong Kwon
The development of ultrathin barrier films is vital to the advanced semiconductor industry. Graphene appears to hold promise as a protective coating; however, the polycrystalline and defective nature of engineered graphene hinders its practical applications. Here, we investigate the oxidation behavior of graphene-coated Cu foils at intrinsic graphene defects of different origins. Macro-scale information regarding the spatial distribution and oxidation resistance of various graphene defects is readily obtained using optical and electron microscopies after the hot-plate annealing...
November 16, 2017: Nature Communications
Michael Rivera Mananghaya, Gil Nonato Santos, Dennis Yu, Catherine Stampfl
The realistic shapes of N doped graphene nanoribbons (GNRs) can be realized by considering nearly zigzag-edged (NZE) imperfections and pyridine defects (3NV). The paper focuses on NZE-GNRs with 3NV that is populated by Scandium abbreviated as Sc/NZE-3NVGNRs. Systematic calculations have clarified roles of the nano-shapes of NZE-3NVGNRs in its formation, energetics, stability and electron states functionalized with Sc using density functional theory (DFT) formalisms. According to DFT calculations, the magnitude of the spin that is attributed to the rise of magnetic order is closely linked to the altered shape of the ribbon edges...
November 16, 2017: Scientific Reports
In Hyuk Son, Jong Hwan Park, Seongyong Park, Kwangjin Park, Sangil Han, Jaeho Shin, Seok-Gwang Doo, Yunil Hwang, Hyuk Chang, Jang Wook Choi
Improving one property without sacrificing others is challenging for lithium-ion batteries due to the trade-off nature among key parameters. Here we report a chemical vapor deposition process to grow a graphene-silica assembly, called a graphene ball. Its hierarchical three-dimensional structure with the silicon oxide nanoparticle center allows even 1 wt% graphene ball to be uniformly coated onto a nickel-rich layered cathode via scalable Nobilta milling. The graphene-ball coating improves cycle life and fast charging capability by suppressing detrimental side reactions and providing efficient conductive pathways...
November 16, 2017: Nature Communications
Filipe Matusalem, Daniel S Koda, Friedhelm Bechstedt, Marcelo Marques, Lara K Teles
Growth of X-enes, such as silicene, germanene and stanene, requires passivated substrates to ensure the survival of their exotic properties. Using first-principles methods, we study as-grown graphene on polar SiC surfaces as suitable substrates. Trilayer combinations with coincidence lattices with large hexagonal unit cells allow for strain-free group-IV monolayers. In contrast to the Si-terminated SiC surface, van der Waals-bonded honeycomb X-ene/graphene bilayers on top of the C-terminated SiC substrate are stable...
November 16, 2017: Scientific Reports
J B Pendry, Paloma Arroyo Huidobro, Yu Luo, Emanuele Galiffi
In advanced field theories, there can be more than four dimensions to space, the excess dimensions described as compacted and unobservable on everyday length scales. We report a simple model, unconnected to field theory, for a compacted dimension realized in a metallic metasurface periodically structured in the form of a grating comprising a series of singularities. An extra dimension of the grating is hidden, and the surface plasmon excitations, though localized at the surface, are characterized by three wave vectors rather than the two of typical two-dimensional metal grating...
November 17, 2017: Science
Long Ju, Lei Wang, Ting Cao, Takashi Taniguchi, Kenji Watanabe, Steven G Louie, Farhan Rana, Jiwoong Park, James Hone, Feng Wang, Paul L McEuen
Excitons, the bound states of an electron and a hole in a solid material, play a key role in the optical properties of insulators and semiconductors. Here, we report the observation of excitons in bilayer graphene (BLG) using photocurrent spectroscopy of high-quality BLG encapsulated in hexagonal boron nitride. We observed two prominent excitonic resonances with narrow line widths that are tunable from the mid-infrared to the terahertz range. These excitons obey optical selection rules distinct from those in conventional semiconductors and feature an electron pseudospin winding number of 2...
November 17, 2017: Science
Congying Wen, Mengmeng Li, Wangbo Li, Zizhou Li, Wei Duan, Yulong Li, Jie Zhou, Xiyou Li, Jingbin Zeng
The content of gasoline fraction in oil samples is not only an important indicator of oil quality, but also an indispensable fundamental data for oil refining and processing. Before its determination, efficient preconcentration and separation of gasoline fractions from complicated matrices is essential. In this work, a thin layer of graphene (G) was deposited onto oriented ZnO nanorods (ZNRs) as a SPME coating. By this approach, the surface area of G was greatly enhanced by the aligned ZNRs, and the surface polarity of ZNRs was changed from polar to less polar, which were both beneficial for the extraction of gasoline fractions...
November 11, 2017: Journal of Chromatography. A
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