Multipyrene terminated hyperbranched polyglycidol (mPHP) has been synthesized and used to non-covalently functionalize pristine graphene sheets (GSs) through π-π stacking interactions. Mediated by the mPHP layer, a variety of metal nanoparticles (Au, Ag and Pt) were in situ generated and deposited onto the surface-modified GS, yielding versatile GS/mPHP/metal nanohybrids. As typical examples, by simply controlling the concentration of HAuCl(4) used, Au nanostructures ranging from isolated spheres to a continuous film were created and coated onto the surface-modified GS. The studies on the fluorescence properties of resulting GS/mPHP/Au hybrid nanostructures reveal that the GS and controllable content of Au components in the hybrids can effectively quench the fluorescence emission of mPHP in a controlled manner. Further investigation indicates that GS/mPHP/Au hybrids are promising surface enhanced Raman scattering (SERS) substrates. The SERS activities of these hybrids depend on the contents and form of the Au. The GS/mPHP/Au hybrid containing continuous Au films exhibits the strongest SERS activity. GS/mPHP/Au hybrids are also used as efficient heterogeneous catalysts for the reduction of 4-NP, and demonstrate excellent catalytic performance. The detailed reaction kinetics and the reusability of such catalysts have also been investigated.
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http://dx.doi.org/10.1039/c2nr11812b | DOI Listing |
Mikrochim Acta
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Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190, Thailand.
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View Article and Find Full Text PDFNanoscale
January 2025
Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580, Japan.
A process technology was developed for transferring strained graphene sheets using an elastomer nanosheet to enhance the resonance characteristics of a graphene resonator. The strain-induced graphene resonator demonstrated a 1.80-fold improvement in the product of resonant frequency and -factor compared to the unstrained resonator.
View Article and Find Full Text PDFACS Nano
January 2025
Materials Science and Engineering Program and Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States.
With the increasing popularity of electric transportation over the past several years, fast-charging lithium-ion batteries are highly demanded for shortening electric vehicles' charging time. Extensive efforts have been made on material development and electrode engineering; however, few of them are scalable and cost-effective enough to be potentially incorporated into the current battery production. Here, we propose a facile magnetic templating method for preparing LiFePO (LFP) cathodes with vertically aligned graphene sheets to realize fast-charging properties at a practical loading of 20 mg cm.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
February 2025
Alan G. MacDiarmid NanoTech Institute, University of Texas at Dallas, Richardson, TX 75080.
The highest sheet symmetry form of graphyne, with one triple bond between each neighboring hexagon in graphene, irreversibly transforms exothermically at ambient pressure and low temperatures into a nongraphitic, planar-sheet, zero-bandgap phase consisting of intrasheet-bonded sp carbons. The synthesis of this sp carbon phase is demonstrated, and other carbon phases are described for possible future synthesis from graphyne without breaking graphyne bonds. While measurements and theory indicate that the reacting graphyne becomes nonplanar because of sheet wrinkling produced by dimensional mismatch between reacted and nonreacted sheet regions, sheet planarity is regained when the reaction is complete.
View Article and Find Full Text PDFSci Rep
January 2025
College of Engineering, Applied Science University (ASU), Manama, Kingdom of Bahrain.
This paper presents an in-depth analytical investigation into the time-dependent flow of a Casson hybrid nanofluid over a radially stretching sheet. The study introduces the effects of magnetic fields and thermal radiation, along with velocity and thermal slip, to model real-world systems for enhancing heat transfer in critical industrial applications. The hybrid nanofluid consists of three nanoparticles-Copper and Graphene Oxide-suspended in Kerosene Oil, selected for their stable and superior thermal properties.
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