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To circumvent the bottlenecks of non-flexibility, low sensitivity, and narrow workable detection range of conventional biosensors for biological molecule detection (e.g., dopamine (DA) secreted by living cells), a new hybrid flexible electrochemical biosensor has been created by decorating closely packed dendritic Pt nanoparticles (NPs) on freestanding graphene paper. This innovative structural integration of ultrathin graphene paper and uniform 2D arrays of dendritic NPs by tailored wet chemical synthesis has been achieved by a modular strategy through a facile and delicately controlled oil-water interfacial assembly method, whereby the uniform distribution of catalytic dendritic NPs on the graphene paper is maximized. In this way, the performance is improved by several orders of magnitude. The developed hybrid electrode shows a high sensitivity of 2 μA cm−2 μ m−1, up to about 33 times higher than those of conventional sensors, a low detection limit of 5 n m, and a wide linear range of 87 n m to 100 μ m. These combined features enable the ultrasensitive detection of DA released from pheochromocytoma (PC 12) cells. The unique features of this flexible sensor can be attributed to the well-tailored uniform 2D array of dendritic Pt NPs and the modular electrode assembly at the oil-water interface. Its excellent performance holds much promise for the future development of optimized flexible electrochemical sensors for a diverse range of electroactive molecules to better serve society. [ABSTRACT FROM AUTHOR]

The excellent electrical conductivity of graphene is due to its highly‐conjugated structures. Manipulation of the electronic and mechanical properties of graphene can be achieved by controlling the destruction of its in‐sheet conjugation system. Herein, we report the preparation of CoCeSx−SA@BPMW@RGO through π‐π stacking interactions at the molecular level. In this study, sodium alginate was reacted with Co2+ and Ce3+, and the composite was loaded onto a graphene surface. The graphene sheets were prepared using a bi‐pyrene terminated molecular wire (BPMW) to avoid re‐stacking of the grapheme sheets, thereby forming nanoscale spaces between sheets. The angle between the BPMW coplanar pyrene group and the phenyl group was 33.2°, and the graphene layer is supported in an oblique direction. Finally, a three‐dimensional porous composite was obtained after annealing and vulcanization. The obtained CoCeSx−SA@BPMW@RGO exhibited excellent electrical conductivity and remarkable cycle stability. When the current density was 1 A g−1, its specific capacitance was as high as 1004 F g−1. BPMW modifies graphene through the synergistic effect of π‐π stacking interaction and special structure to obtain excellent electrochemical performance. Moreover, a solid‐state asymmetric supercapacitor device was fabricated based on the synthesized CoCeSx−SA@BPMW@RGO hybrid, which exhibited a power density of 979 W kg−1 at an energy density of 23.96 Wh kg−1. [ABSTRACT FROM AUTHOR]

In this report, sandwiched Ni2P nanoparticles encapsulated by graphene sheets are first synthesized by directly encapsulating functional units in graphene sheets instead of fabricating separate graphene sheets and then immobilizing the functional components onto the generated surfaces. In this strategy, we use low-cost, sustainable and environmentally friendly glucose as a carbon source and NiNH4PO4 ⋅H2O nanosheets as sacrificial templates. This unique structure obtained here cannot only prevent the nanoparticles from aggregation or loss but also enhance the electronic conductivity compared to the independent nanoparticles. Furthermore, the novel sandwich-like Ni2P/C can be applied in plenty of fields, especially in electrical energy storage. In this paper, a series of electrochemical tests of the sandwich-like Ni2P/C are carried out, which demonstrate the excellent cyclic stability and rate capacity for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

It is extremely desirable to explore high-efficient, affordable and robust oxygen electrocatalysts toward rechargeable Zn–air batteries (ZABs). A 3D porous nitrogen-doped graphene encapsulated metallic Ni3 Fe alloy nanoparticles aerogel (Ni3Fe-GA1) was constructed through a facile hydrothermal assembly and calcination process. Benefiting from 3D porous configuration with great accessibility, high electrical conductivity, abundant active sites, optimal nitrogen content and strong electronic interactions at the Ni3Fe/ N-doped graphene heterointerface, the obtained aerogel showed outstanding catalytic performance toward the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Specifically, it exhibited an overpotential of 239 mV to attain 10 mAcm-2 for OER, simultaneously providing a positive onset potential of 0.93 V within a half-wave potential of 0.8 V for ORR. Accordingly, when employed in the aqueous ZABs, Ni3Fe-GA1 achieved higher power density and superior reversibility than Pt/C-IrO2 catalyst, making it a potential candidate for rechargeable ZABs. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) enwrapped SiO2/TiO2 hollow nanoparticles (GO-HNP) are synthesized by the Stöber method and used as a nanocarrier for loading protoporphyrin IX (PpIX). The synthesized nanoparticle has high dispersibility and high uniformity in diameter (ca. 50 nm). Furthermore, this nanoparticle shows λ=808 nm laser induced PpIX release properties (photoinduced 'on-off' drug-release system). GO-HNP-PpIX is employed for inducing both photothermal therapy (PTT) and photodynamic therapy (PDT). The synergic effect of PTT and PDT exhibits powerful anticancer properties. When cancer cells are treated with GO-HNP-PpIX and irradiated with both visible light and a NIR laser, the cell viability drops dramatically to 2.5 %, which is an anticancer effect approximately 13 times higher than that obtained in a previous study. Moreover, no significant cell damage has been observed under λ=808 nm laser irradiation. The GO-HNP-PpIX system suggests an external stimuli-responsive efficient anticancer treatment effect toward human breast cancer cells. [ABSTRACT FROM AUTHOR]

The development of highly sensitive and selective methods for the detection of lead ion (Pb2+) is of great scientific importance. In this work, we develop a new surface-enhanced Raman scattering (SERS)-based sensor for the selective trace measurement of Pb2+. The SERS-based sensor is assembled from gold nanoparticles (AuNPs) and graphene using cucurbit[7]uril (CB[7]) as a precise molecular glue and a local SERS reporter. Upon the addition of Pb2+, CB[7] forms stronger complexes with Pb2+ and desorbs from AuNPs, resulting in a sensitive 'turn-off' of SERS signals. This SERS-based assay shows a limit of detection (LOD) of 0.3 n m and a linear detection range from 1 n m to 0.3 μ m for Pb2+. The feasibility of the assay is further demonstrated by probing Pb2+ in real water samples. This SERS-based analytical method is highly sensitive and selective, and therefore holds promising applications in environmental analysis. [ABSTRACT FROM AUTHOR]

A general strategy based on the nanoscale Kirkendall effect has been developed to grow hollow transition metal (Fe, Co or Ni) oxide nanoparticles on graphene sheets. When applied as lithium-ion battery anodes, these hollow transition metal oxide-based composites exhibit excellent electrochemical performance, with high reversible capacities and long-term stabilities at a high current density, superior to most transition metal oxides reported to date. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) have attracted much interest as a low-cost and environmentally benign energy storage system, but more attention is justifiably required to address the major technical issues relating to the anode materials to deliver high reversible capacity, superior rate capability, and stable cyclability. A SnSe/reduced graphene oxide (RGO) nanocomposite has been prepared by a facile ball-milling method, and its structural, morphological, and electrochemical properties have been characterized and compared with those of the bare SnSe material. Although the redox behavior of SnSe remains nearly unchanged upon the incorporation of RGO, its electrochemical performance is significantly enhanced, as reflected by a high specific capacity of 590 mA h g−1 at 0.050 A g−1, a rate capability of 260 mA h g−1 at 10 A g−1, and long-term stability over 120 cycles. This improvement may be attributed to the high electronic conductivity of RGO, which also serves as a matrix to buffer changes in volume and maintain the mechanical integrity of the electrode during (de)sodiation processes. In view of its excellent Na+ storage performance, this SnSe/RGO nanocomposite has potential as an anode material for SIBs. [ABSTRACT FROM AUTHOR]

Composite powders of the configuration Si@carbon@void@graphene were prepared by a one-step spray pyrolysis process, by adding polyvinylpyrrolidone (PVP) to a precursor solution containing graphene oxide (GO) sheets and silicon nanoparticles (NPs). Morphological analysis indicates that the individual Si NPs are coated with amorphous carbon and encapsulated in a micrometer-sized graphene ball structure that offers a large amount of buffer space. The addition of PVP improves the stability of the colloidal spray solution containing the GO sheets and the Si NPs. Consequently, the prepared Si@C@void@graphene composite powders have a relatively more uniform morphology than the Si@void@graphene composite powders prepared from the spray solution without PVP. The first charge and discharge capacities of the Si@C@void@graphene electrode measured at 0.1 A g−1 are as high as 3102 and 2215 mA h g−1, respectively. With an increase in the current rate from 0.5 to 11 A g−1, 46 % of the original capacity (i.e., 2134 mA h g−1) is maintained. After 500 cycles at a high rate of 7 A g−1, the Si@C@void@graphene electrode shows 84 % capacity retention and 99.8 % of the average Coulombic efficiency. The superior cycling and rate capabilities of the prepared Si@C@void@graphene electrode could be attributed to the uniform carbon coating of the Si NPs and the graphene ball structure, which facilitates efficient diffusion of Li ions and prevents the penetration of electrolyte into graphene ball during cycling. [ABSTRACT FROM AUTHOR]

Core-shell carbon-coated LiFePO4 nanoparticles were hybridized with reduced graphene (rGO) for high-power lithium-ion battery cathodes. Spontaneous aggregation of hydrophobic graphene in aqueous solutions during the formation of composite materials was precluded by employing hydrophilic graphene oxide (GO) as starting templates. The fabrication of true nanoscale carbon-coated LiFePO4-rGO (LFP/C-rGO) hybrids were ascribed to three factors: 1) In-situ polymerization of polypyrrole for constrained nanoparticle synthesis of LiFePO4, 2) enhanced dispersion of conducting 2D networks endowed by colloidal stability of GO, and 3) intimate contact between active materials and rGO. The importance of conducting template dispersion was demonstrated by contrasting LFP/C-rGO hybrids with LFP/C-rGO composites in which agglomerated rGO solution was used as the starting templates. The fabricated hybrid cathodes showed superior rate capability and cyclability with rates from 0.1 to 60 C. This study demonstrated the synergistic combination of nanosizing with efficient conducting templates to afford facile Li+ ion and electron transport for high power applications. [ABSTRACT FROM AUTHOR]

New Pd and Pt catalysts with high catalytic efficiency have been fabricated by means of a self‐assembly strategy and are composed of four components, that is, noble metal, CeO2, Fe3O4, and reduced graphene oxide (RGO). The as‐obtained Pd and Pt catalysts have relatively high catalytic activity and stability in the selective hydrogenation of p‐nitrophenol; they are also stable in air and exhibit a good magnetic response. For more details see the Full Paper by H. Zhang et al. on page 5169 ff. [ABSTRACT FROM AUTHOR]

A new and general fabrication strategy towards encapsulation of nanoparticles, such as Ni, Co and Co3O4, in sandwiched graphene sheets is reported in the Full Paper by Y. Wang et al. on page 3340 ff. The nanoparticles‐encapsulated sandwiched graphene sheets possess unique structures, in which nanoparticles are strictly confined inside and the graphene sheets are layered on both outer sides like a three‐layered sandwich, and substantially enhanced properties derived from the synergic effect among the individual functional components. The picture also shows the Chongqing University founded in 1929. The Chinese words in silver white mean top left to bottom right: “Unity, Diligence, Truth, Innovation” as the University motto. [ABSTRACT FROM AUTHOR]

Porous graphene with catalytically active ceria nanometre‐size particles were prepared using pulsed laser deposition (PLD) on graphene produced through chemical vapour deposition (CVD). The reported process provided porous graphene containing ceria nanoparticles as confirmed by HR TEM and XPS. Isotopically labelled 13C graphene was employed to study desorption of the species containing carbon. Methanol adsorption was utilised to probe the nature of the catalytic activity of prepared ceria decorated graphene. The important role of graphene support for the stabilization of reduced ceria nanoparticles was finally confirmed. Increased dehydrogenation activity of graphene with ceria nanoparticles leading to CO and H2 formation was demonstrated. [ABSTRACT FROM AUTHOR]

Abstract: Visible‐light‐driven conversion of CO2 to CO and high‐value‐added carbon products is a promising strategy for mitigating CO2 emissions and reserving solar energy in chemical form. We report an efficient system for CO2 transformation to CO catalyzed by bare CoP, hybrid CoP/carbon nanotubes (CNTs), and CoP/reduced graphene oxide (rGO) in mixed aqueous solutions containing a Ru‐based photosensitizer, under visible‐light irradiation. The in situ prepared hybrid catalysts CoP/CNT and CoP/rGO show excellent catalytic activities in CO2 reduction to CO, with a catalytic rates of up to 39 510 and 47 330 μmol h−1 g−1 in the first 2 h of reaction, respectively; a high CO selectivity of 73.1 % for the former was achieved in parallel competing reactions in the photoreduction of CO2 and H2O. A combination of experimental and computational studies clearly shows that strong interactions between CoP and carbon‐supported materials and partially adsorbed H2O molecules on the catalyst surface significantly improve CO‐generating rates. [ABSTRACT FROM AUTHOR]

A general strategy based on the nanoscale Kirkendall effect is developed to grow hollow transition metal (Fe, Co or Ni) oxide nanoparticles on graphene sheets. When applied as lithium‐ion battery anodes, these hollow transition metal oxide based composites exhibit excellent electrochemical performance with high reversible capacities and long‐term stabilities at a high current density, superior to most transition metal oxides reported to date. More information can be found in the Full Paper by Y. Chen, C. Sun, P. Gao et al. on page 1638 ff. [ABSTRACT FROM AUTHOR]

In this article, the two-layersandwiched graphene@LiFe0.2 Co0.8 O2 nanoparticles (SG@LFCO) have been prepared and investigated as high-rateand long-life cathode materials for rechargeable lithiumion batteries. The materials possess a high-surface area (267.1 m² g-1 )and lots of void spaces. By combining various favorable conditions, such as Fe doping, coating graphene, and designing novel morphology,the as-prepared materials deliver aspecific capacity of 115 mAhg-1 at 10 C. At the 0.1 Ccycling rate, the capacityretention of 97.2% issustained after 250 cycles and acoulombic efficiencyofaround 97.6% is obtained. [ABSTRACT FROM AUTHOR]

A correction to the article "Enhanced Photocatalytic Hydrogen-Production Performance of Graphene-Zn xCd1xS Composites by Using an Organic S Source" in the 2014 issue is presented.

Label-free logic gates (AND, OR, and INHIBIT) based on chemiluminescence (CL) as new optical readout signal have been developed by taking advantage of the unique CL activity of luminol- and lucigenin-functionalized gold nanoparticles/graphene oxide (luminol-lucigenin/AuNPs/GO) nanocomposites. It was found that Fe2+ ions could induce the CL emission of luminol-lucigenin/AuNPs/GO nanocomposites in alkaline solution. On this basis, by using Fe2+ ions and NaOH as the inputs and the CL signal as the output, an AND logic gate was fabricated. When the initial reaction system contained luminol-lucigenin/AuNPs/GO nanocomposites and NaOH, either Fe2+ ions or Ag+ ions could react with the luminol-lucigenin/AuNPs/GO nanocomposites to produce a strong CL emission. This result was used to design an OR logic gate using Fe2+ ions and Ag+ ions as the inputs and CL signal as the output. Moreover, two INHIBIT logic gates for Fe2+ and Ag+ were also developed using by NaClO and L-cysteine as their CL inhibitors, respectively. Furthermore, the proposed logic gates were successfully used to detect Fe2+, Ag+, and L-cysteine, respectively. The developed logic gates may find future applications in sensing, clinical diagnostics, and environmental monitoring. [ABSTRACT FROM AUTHOR]

A new approach for the fabrication of transparent, antireflective, conductive and superhydrophilic multifunctional hybrid films through the layer-by-layer (LbL) assembly of reduced graphene oxide (RGO) nanosheets and SiO2 nanoparticles is reported. The RGO nanosheets, SiO2 nanoparticles and films were characterized by means of transmission electron microscopy, UV/Vis absorption spectrophotometry, Raman spectroscopy, atomic force microscopy, contact angle/interface system, and a four-point probe. It was found that the graphene/SiO2 hybrid films exhibited a significant increase in transmittance as compared with RGO films. The optical, electronic and wetting properties of hybrid films could be manipulated by rational design of the film structure and variation of the cycle number of the LbL assembly. The obtained transparent, conductive, and superhydrophilic graphene/SiO2 hybrid films showed excellent antireflective, antistatic, and antifogging behaviors. The remarkable performance could be attributed to the combination of electrical conductivity of RGO nanosheets and superhydrophilic antireflective surface derived from SiO2 nanoparticles. [ABSTRACT FROM AUTHOR]

A new photoelectrochemical (PEC) biosensor was developed by using carboxyl-functionalized graphene and CdSe nanoparticles. This sensitive interface was then successfully applied to detection of thrombin based on the dual-quenched effect of PEC nanoparticle, which relied on the electron transfer of a bipyridinium relay and energy transfer of AuNPs. After recognition with an aptamer, the PEC nanoparticle was removed and a signal-on PEC biosensor was obtained. Moreover, the bio-barcode technique used in the preparation of PEC nanoparticle could avoid cross-reaction and enhances the sensitivity. Taking advantages of the various methods mentioned above, the sensitivity could be easily enhanced. In addition, in this work we also investigated graphene that was modified with different functional groups and AuNPs of different particle sizes. Under optimal conditions, a detection limit of 5.9×10−15 M was achieved. With its simplicity, selectivity, and sensitivity, this strategy shows great promise for the fabrication of highly efficient PEC biosensors. [ABSTRACT FROM AUTHOR]

A new approach based on far infrared-assisted in situ reduction was developed for the facile one-step preparation of graphene-nickel nanoparticle hybrid by refluxing a mixture solution containing graphene oxide, nickel(II) sulfate, and hydrazine over an far-infrared heater. The reduction time was as short as 20 min. The structure of the material was investigated by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy, vibrating sample magnetometery, and Fourier transform infrared spectroscopy. Magnetic investigations indicate that the grapheme-nickel nanoparticle hybrid exhibits ferromagnetic behavior at room temperature. Meanwhile, the hybrid was successfully employed in the enrichment and identification of proteins and peptides in combination with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry based on its excellent magnetic responsibility, high dispersibility, large surface area, and hydrophobicity, indicating great promise for a wide range of applications. [ABSTRACT FROM AUTHOR]