Phytic acid (PA), which is a natural and innoxious plant constituent, can strongly adsorb on the metal surface because of its six phosphate groups. In this work, based on the chelating properties of ...PA and the reaction between PA and hydrolyzable vinyltriethoxysilane (VTES), we developed a novel and facial strategy to generate hierarchical-layer nanospheres on the metal mesh surface and fabricated robust superhydrophobic and superoleophilic miniature metal mesh ships. Because of their superwetting properties, the modified meshes could easily remove and recycle the oil spills from the water surface (>90% collection efficiency), and have high oil/water separation capacity (>96%). The excellent stability, corrosion resistance, and robust mechanical durability endow the modified mesh ships with more advantages in a marine environment. We envision that these superhydrophobic meshes modified with PA and VTES are sustainable, environmentally friendly, and easy to scale up and hence display great potential in practical application.
Highly stable dispersions of nanosized copper particles with an average particle size less than 2 nm were synthesized using a straightforward, cost-effective, and green method. Nontoxic l-ascorbic ...acid was utilized as both a reducing agent and capping agent precursor in aqueous medium. The copper particles were characterized by ultraviolet-visible spectroscopy, transmission electron microscopy, and Fourier-transform infrared spectroscopy The mechanism of l-ascorbic acid on the reduction and stabilization of copper nanoparticles is also discussed.
Reduced graphene oxide (r-GO) paper is easily synthesized by a flame-induced reduction of graphene oxide (GO) paper under ambient conditions. The X-ray diffraction and X-ray photoelectron ...spectroscope results confirm the effectivity of the flame-induced reduction. The resulting r-GO paper has a high surface area of 274.9 m2 g−1 and contains a certain amount of oxygen-containing groups. Electrochemical behaviors of the electrode built with the r-GO paper are investigated in two kinds of electrolytes, 2 M KOH aqueous solution and 1 M Et4NBF4-acetonitrile solution, respectively. The results show that the high values of the specific capacitance for the r-GO can be obtained in both electrolytes, which reach 212 and 160 F g−1 at the same current density of 1 A g−1 respectively. Also, the r-GO-based electrode and supercapacitor exhibits stable cycling performance. The good capacitive performances in KOH aqueous electrolyte are due to the high surface area and the remaining oxygen containing groups of the r-GO paper.
Display omitted A flame synthesis method has been developed to prepare graphene from direct flame reduction of graphene oxide paper under ambient conditions, and the reduced graphene oxide exhibit very good electrochemical properties in KOH aqueous solution and 1 M Et4NBF4 in acetonitrile, respectively.
► Reduced graphene oxide paper was prepared by direct flame reduction method. ► As-prepared graphene has high surface area and abundant oxygen containing groups. ► As-prepared graphene exhibited excellent supercapacitive performance.
Graphene(G)-based polymer nanocomposites have attracted great interest owing to their superior physicochemical properties over polymers. However, the tendency of graphene sheets to aggregate makes it ...difficult to achieve homogenous dispersion in polymer matrix. Herein, by utilization of poly(2-butylaniline) (P2BA) as a dispersing agent, stable dispersion of graphene in organic solvents was achieved via non-covalent π-π interactions between P2BA and graphene nanosheets. The exfoliated graphene nanosheets were then integrated with coating matrix by curing reaction of epoxy resin with P2BA functionalized graphene (P2BA-G) and amine hardener. Embedding a small percentage of well-dispersed graphene nanosheets (P2BA0.5%-G0.5%) in epoxy coating remarkably improved anticorrosion performance and wear resistance properties, which was attributed to the synergistic effects of the redox catalytic capability of P2BA, high mechanical and barrier properties of well-dispersed graphene nanosheets in the epoxy matrix. The present study provides a promise strategy for development of graphene reinforced organic coatings with superior physical-mechanical properties for metal protection.
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•MgAl-NO2 LDH was synthesized by acidizing shock treatment of Mg-Al-CO3 and ion exchange.•LDH can be regarded as a transit station, receiving chloride ions and releasing nitrite ...ions.•The electrochemical impedance of the coating improved significantly after adding LDH nanofillers.•Controllable release of nitrite realizes self-repairing of coatings
Layered double hydroxide (LDH) with NO2− intercalation was successfully prepared via acidification oscillation and ion exchange. The nano-fillers were incorporated into the resin to prepare anti-corrosion coatings with the thickness of ca. 50 ± 5 μm. The electrochemical and self-repairing properties of the LDH-doped coatings were studied by EIS and LEIS. Results indicated that the addition of LDH loaded with nitrite induced obvious increased in the impedance of coating (from 4.64 × 108 Ω cm2 to 2.14 × 1010 Ω cm2) and improved the anticorrosion performance of the coating. In addition, the localized corrosion of coatings could be largely inhibited, and the released nitrite ions from LDH interlayers exhibited active anticorrosion functions. When LDH nanosheets were added to the coatings, the lamella structures improved the barrier performances of the coatings. At the same time, the excellent ion exchanges ability of LDH could be used as storage stations for chloride ions, and the release of nitrite ions could play an active anti-corrosion role. Both of them cooperated to synergistically improve the anti-corrosion performance of the coating.
In comparison with graphene sheets, graphene quantum dots (GQDs) exhibit novel chemical/physical properties including nanometer-size, abundant edge defects, good electrical conductivity, high ...mobility, chemical inertia, stable photoluminescence and better surface grafting, making them promising for fabricating various novel devices. In the present work, an asymmetric micro-supercapacitor, using GQDs as negative active material and polyaniline (PANI) nanofibers as positive active material, is built for the first time by a simple and controllable two-step electro-deposition on interdigital finger gold electrodes. Electrochemical measurements reveal that the as-made GQDs//PANI asymmetric micro-supercapacitor has a more excellent rate capability (up to 1000 V s(-1)) than previously reported electrode materials, as well as faster power response capability (with a very short relaxation time constant of 115.9 μs) and better cycling stability after 1500 cycles in aqueous electrolyte. On this basis, an all-solid-state GQDs//PANI asymmetric micro-supercapacitor is fabricated using H3PO4-polyvinyl alcohol gel as electrolyte, which also exhibits desirable electrochemical capacitive performances. These encouraging results presented here may open up new insight into GQDs with highly promising applications in high-performance energy-storage devices, and further expand the potential applications of GQDs beyond the energy-oriented application of GQDs discussed above.
In this work we report a low cost technique,
via
simple rapid-mixture polymerization of aniline using an electrospun carbon nanofiber (CNF) paper as substrate, to fabricate free-standing, flexible ...CNF-PANI (PANI = polyaniline) composite paper. The morphology and microstructure of the obtained products are characterized by FESEM, FTIR, Raman and XRD. As results, PANInanoparticles are homogeneously deposited on the surface of each CNF, forming a thin, light-weight and flexible composite paper. The resulting composite paper displays remarkably enhanced electrochemical capacitance compared with the CNF paper, making it attractive for high-performance flexible capacitors.
A combination of electrospinning and rapid-mixture polymerization techniques has been successfully utilized to prepare freestanding and flexible CNF-PANI composite paper, which displays remarkably enhanced electrochemical capacitance compared with the pristine CNF paper.
In this work, we report a low-cost technique via simple rapid-mixture polymerization of aniline using graphene oxide (GO) and graphene papers as substrates, respectively, to fabricate free-standing, ...flexible GO−polyaniline (PANI) and graphene−PANI hybrid papers. The morphology and microstructure of the obtained papers were characterized by FESEM, FTIR, Raman, and XRD. As results, nanostructural PANI can be deposited on the surfaces of GO and graphene papers, forming thin, lightweight, and flexible paperlike hybrid papers. The hybrid papers display a remarkable combination of excellent electrochemical performances and biocompatibility, making the paperlike materials attractive for new kinds of applications in biosciences.
► A flexible and freestanding carbon nanofiber/graphene nanosheet (CNF/GNS) composite paper is prepared. ► The GNSs are distributed uniformly among and in the CNFs. ► The GNS/CNF composite paper ...exhibits the largest specific capacitance of 197
F
g
−1, about 24% higher than that of pure CNF paper. ► The GNS/CNF composite exhibited good cycling stability and lifetime.
In this work, a flexible and freestanding carbon nanofiber/graphene nanosheet (CNF/GNS) composite paper is prepared via electrospinning followed by high-temperature annealing using a polyacrylonitrile/GNS/dimethylformamide mixture as electrospun precursor. The structure characterizations show that GNS homogeneously distributes in the CNF, forming a thin, light-weight and flexible composite paper. Due to the reinforcing effects coming from CNF and GNS, the Brunauer Emmett Teller (BET) specific surface area, conductivity and capacitance performance of pure CNF are significantly improved after adding GNS. The GNS/CNF composite paper exhibits the largest specific capacitance of 197
F
g
−1, about 24% higher than that of pure CNF paper. Therefore, based on the above investigations, such GNS/CNF composite paper can be a potential candidate for high-performance flexible capacitors.
The use of graphene and multi-walled carbon nanotubes (MWCNTs) additives as lubricants has received considerable interest because of their excellent mechanical and frictional properties. Given their ...structural differences, both carbon nano-additives are expected to have different synergistic effects at various conditions (from boundary to mixed lubrication). For applications in space, the tribological properties of graphene and MWCNTs additives in diamond-like carbon/ionic liquids hybrid films in different lubricating states at high vacuum were compared. The wear surfaces, transfer films, wear debris, and microstructures of the hybrid films were analyzed via Raman spectroscopy, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. The results showed that MWCNTs and graphene present the different nano-scale tribological mechanisms and produce different lubricating effect on the hybrid films at different lubricating states.
