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Binders play a critical role in rechargeable lithium‐ion batteries (LIBs) by holding granular electrode materials, conductive carbons, and current collectors firmly together to form and maintain a continuous electron conduction phase with sufficient mechanical strength. In the commercial LIBs, the dominant binder is polyvinylidene fluoride for the cathode (LiCoO2, LiFePO4, LiNixCotyMnzO2, etc.) and carboxyl methylcellulose/styrene‐butadiene rubber for the anode (graphite and Li4Ti5O12). However, these polymer binders have several drawbacks, particularly, a lack of electronic and lithium‐ion conductivities. Here, a novel organic/inorganic hybrid conductive binder (LAP‐rGO) for both the anode and cathode of LIBs is reported. The binder consists of 2D reduced graphene oxide sheets with anchored long alkane chains. Electrodes prepared using this binder exhibit sufficient high bond strength, fast electrolyte diffusion, high rate charge/discharge performance, and excellent cycling stability. Around 130 mAh g−1 capacity enhancement at 5C is demonstrated for LiFePO4 and Li4Ti5O12 electrodes owing to the combined improvement in electron and lithium ion transportation. LAP‐rGO bond graphite anode shows specific capacity beyond its theoretical value. Electrode slurries prepared using this new binder have superior processing and coating properties that can be prepared under a high humidity and dried using less energy. [ABSTRACT FROM AUTHOR]

A breakthrough in graphene‐oxide/silicon heterojunction solar cells is presented in which edge‐oxidized graphene and an in‐plane charge transfer dopant (Nafion) are combined to form a high‐quality passivating contact scheme. A graphene oxide (GO):Nafion ink is developed and an advanced back‐junction GO:Nafion/n‐Si solar cell with a high‐power conversion efficiency (18.8%) and large area (5.5 cm2) is reported. This scalable solution‐based processing technique has the potential to enable low‐cost carbon/silicon heterojunction photovoltaic devices. [ABSTRACT FROM AUTHOR]

As a recently emerging group of 2D materials, MXene has attracted extensive attention in the energy storage field in recent years owing to their outstanding features. However, the notorious issues of inevitable oxidation stability and surface‐to‐surface self‐restacking for MXene significantly prevent its further wide‐ranging application. Herein, the 3D macroporous oxidation‐resistant Ti3C2Tx MXene/graphene/carbon nanotube (MRC) hybrid hydrogels are prepared by a simple gelation method assisted by l‐cysteine as crosslinker and l‐ascorbic acid (VC) as reductant. Benefitting from the effectively alleviated restacking, excellent electrical conductivity, and the 3D inter‐crosslinked macroporous architecture, as a supercapacitor electrode, the obtained MRC aerogel exhibits a superior specific capacitance of 349 F g−1, unparalleled rate capability (52.0% at 3000 mV s−1) and amazing cyclic stability (retention of 97.1% after 100 000 cycles). Moreover, the 3D MRC‐30 aerogel exhibits an impressive oxidation‐resistant performance with just a 9.3% increase in electrical resistance after storing in ambient condition for 60 days, effectively alleviating the oxidation problem of MXene. This work demonstrates a new method for construction of 3D oxidation‐resistant MXene hydrogel, shedding new light on the promising applications of MXene materials, especially in high humidity and oxygen environment. [ABSTRACT FROM AUTHOR]

The band structure of bilayer graphene is tunable by introducing a relative twist angle between the two layers, unlocking exotic phases, such as superconductors and Mott insulators, and providing a fertile ground for new physics. At intermediate twist angles around 10°, highly degenerate electronic transitions hybridize to form excitonic states, a quite unusual phenomenon in a metallic system. We probe the bright exciton mode using resonant Raman scattering measurements to track the evolution of the intensity of the graphene Raman G peak, corresponding to the E2g phonon. By cryogenically cooling the sample, we are able to resolve both the incoming and outgoing resonances in the G peak intensity evolution as a function of excitation energy, a prominent manifestation of the bright exciton serving as the intermediate state in the Raman process. For a sample with twist angle 8.6°, we report a weakly temperature dependent resonance broadening γ ≈ 0.07 eV. In the limit of small inhomogeneous broadening, the observed γ places a lower bound for the bright exciton scattering lifetime at 10 fs in the presence of charges and excitons excited by the light pulse for the Raman measurement, limited by the rapid exciton–exciton and exciton–charge scattering in graphene. [ABSTRACT FROM AUTHOR]

2D MXene materials have attracted intensive attention in energy storage application. However, MXene usually undergoes serious face‐to‐face restacking and inferior stability, significantly preventing its further commercial application. Herein, to suppress the oxidation and self‐restacking of MXene, an efficient and fast self‐assembly route to prepare a 3D porous oxidation‐resistant MXene/graphene (PMG) composite with the assistance of an in situ sacrificial metallic zinc template is demonstrated. The self‐assembled 3D porous architecture can effectively prevent the oxidation of MXene layers with no evident variation in electrical conductivity in air at room temperature after two months, guaranteeing outstanding electrical conductivity and abundant electrochemical active sites accessible to electrolyte ions. Consequently, the PMG‐5 electrode possesses a striking specific capacitance of 393 F g−1, superb rate performance (32.7% at 10 V s−1), and outstanding cycling stability. Furthermore, the as‐assembled asymmetric supercapacitor possesses a pronounced energy density of 50.8 Wh kg−1 and remarkable cycling stability with a 4.3% deterioration of specific capacitance after 10 000 cycles. This work paves a new avenue to solve the two long‐standing significant challenges of MXene in the future. [ABSTRACT FROM AUTHOR]

A fast one‐step arc discharge exfoliation method is employed to synthesize Si/graphene composites by using a graphite rod filled with a mixture of Si powder and urea as a cathode. During the arc discharge process, the use of urea allows both the introduction of nitrogen atoms into the graphene and the uniform sealing of Si nanoparticles between the thin graphene sheets to occur simultaneously. The resulting N‐doped graphene nanosheets embedded with Si (Si@NG) can act as an electrode material for lithium‐ion batteries and delivers the reversible capacity of 1030 mAh g−1 with a current density of 200 mA g−1 over 100 cycles along with an outstanding coulombic efficiency of 96.84 %. The remarkable electrochemical rate capability performance can be owed to the multiple role of NG, which not only serves as a three‐dimensional conductive support, but also effectively limits the volume variation of Si nanoparticles. The approach proposed here is expected to be extended to the preparation of other alloy anode/graphene hybrids for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Polydopamine modified reduced graphene oxides (PDA‐rGO) are synthesized by a facile dopamine polymerization reaction. As‐prepared PDA‐rGO shows a capable electrochemical performance as an electrode material for supercapacitors. A capacitance of 120 F g−1 is achieved at current density of 2 A g−1. PDA‐rGO also presents a superior cycling performance with capacitance retention of ∼99% after 10000 cycles. The remarkable electrochemical performance is attributed to the addition of PDA, which prevents the stacking of rGO and enhances the wettability of composite. Meanwhile, the rGO with high conductivity promise fast electronic transport. Polydopamine modified reduced graphene oxides (PDA‐rGO) are synthesized by a facile dopamine polymerization reaction. A capacitance of 120 F g−1 is achieved at current density of 2 A g−1. PDA‐rGO also presents a superior cycling performance with capacitance retention of ∼99% after 10000 cycles. The remarkable electrochemical performance is attributed to the addition of PDA, which prevents the stacking of rGO and enhances the wettability of composite. [ABSTRACT FROM AUTHOR]

NiMoO4 has attracted intensive attention as one of the promising ternary metal oxides because of its high specific capacitance and electrical conductivity compared to traditional transition-metal oxides. In this study, NiMoO4 nanorods uniformly decorated on graphene nanosheets (G-NiMoO4) are synthesized through a facile hydrothermal method. The prepared G-NiMoO4 composite exhibits a high specific capacitance of 714 C·g−1 at 1 A·g−1 and an excellent rate capability, with a retention ratio of 57.7% even at 100 A·g−1. An asymmetric supercapacitor (ASC) fabricated with the G-NiMoO4 composite as the positive electrode and Fe2O3 quantum dot-decorated graphene (G-Fe2O3-QDs) as the negative electrode delivers an ultrahigh energy density of 130 Wh·kg−1, which is comparable to those of previously reported aqueous NiMoO4-based ASCs. Even when the power density reaches 33.6 kW·kg−1, an energy density of 56 Wh·kg−1 can be maintained. The ASC device exhibits outstanding cycling stability, with a capacitance retention of 113% after 40,000 cycles. These results indicate that the G-NiMoO4 composite is a promising candidate for ASCs with ultrahigh energy density and excellent cycling stability. Moreover, the present work provides an exciting guideline for the future design of high-performance supercapacitors for industrial and consumer applications via the simultaneous use of various pseudocapacitive materials with suitable potential windows as the positive and negative electrodes. [ABSTRACT FROM AUTHOR]

Abstract: As an alternative approach for N2 fixation under milder conditions, electrocatalytic nitrogen reduction reaction (NRR) represents a very attractive strategy for sustainable development and N2 cycle to store and utilize energy from renewable sources. However, the research on NRR electrocatalysts still mainly focuses on noble metals, while, high costs and limited resources greatly restrict their large‐scale applications. Herein, as a proof‐of‐concept experiment, taking PdCu amorphous nanocluster anchored on reduced graphene oxide (rGO) as NRR catalysts, the optimum Pd0.2Cu0.8/rGO composite presents a synergistic effect and shows superior electrocatalytic performance toward NRR under ambient conditions (yield: 2.80 µg h−1 mgcat.−1 at −0.2 V vs reversible hydrogen electrode), which is much higher than that of monometallic, especially noble metal, counterparts. The superior catalytic performance of alloy catalysts with low noble metal loading would strongly spur interest toward more researches on NRR catalysts in the future. [ABSTRACT FROM AUTHOR]

3D graphene-carbon nanotubes (G-CNTs) composite with unique morphology and structure was prepared by one-step insertion of CNTs into graphene. Subsequently, the G-CNTs composite as a fiber coating material for solid-phase microextraction (SPME) was fabricated on the surface of a stainless steel wire by direct coating method. The prepared coating was tested by the extraction of benzene homologues (BTEX, benzene, toluene, ethylbenzene and m-xylene). Compared with a commercial polydimethylsiloxane (PDMS) fiber, the home-made coating exhibited higher extraction performance for BTEX, and the reasons were discussed systematically. Under the optimized conditions, the prepared coating coupled with chromatography-mass spectrometry (GC–MS) for the analysis of BTEX exhibited wide linear ranges, low limits of detection (3 S/N) (LODs, 0.59–2.68 ng L −1 ), low limits of quantification (10 S/N) (LOQs, 1.96–8.92 ng L −1 ), good repeatability (3.2–5.5%, n = 6) and reproducibility (3.7–9.1%, n = 3). Finally, the developed method was successfully applied to the analysis of BTEX in environmental water samples with satisfactory recoveries (84.7–108.1%). This study is expected to further the exploration of high-performance SPME coating materials, and broaden the applications of graphene-based materials. [ABSTRACT FROM AUTHOR]

Large-sized graphene sheets (LG) and doping strategy were employed to fabricate lightweight and flexible graphene paper with exceptional electromagnetic interference (EMI) shielding performance. Compared with the smaller sized ones, LG with fewer defects and more conjugated carbon domain size as well as better alignment result in higher electrical conductivity and strength of graphene paper. The iodine doping further improves the carrier density of LG by formation of triiodide ( I 3 − ) and pentaiodide ( I 5 − ) through charge transfer process without deteriorating the mechanical property, thus leading to superior EMI shielding effectiveness (SE). The EMI SE of iodine doped LG film with thickness of 12.5 μm is up to ∼52.2 dB at 8.2 GHz, which is much higher than that of undoped LG with the same thickness (∼47.0 dB). More important, the improvements in EMI SE is contributed to the SE absorption, while the SE reflection is almost unchanged. The mechanisms of improved EMI shielding performance as well as mechanical property were investigated and discussed. The present study provides a facile way to fully develop graphene in lightweight and flexible EMI shielding materials and devices. [ABSTRACT FROM AUTHOR]

A strategy to prepare flexible and conductive MXene/graphene (reduced graphene oxide, rGO) supercapacitor electrodes by using electrostatic self-assembly between positively charged rGO modified with poly(diallyldimethylammonium chloride) and negatively charged titanium carbide MXene nanosheets is presented. After electrostatic assembly, rGO nanosheets are inserted in-between MXene layers. As a result, the self-restacking of MXene nanosheets is effectively prevented, leading to a considerably increased interlayer spacing. Accelerated diffusion of electrolyte ions enables more electroactive sites to become accessible. The freestanding MXene/rGO-5 wt% electrode displays a volumetric capacitance of 1040 F cm-3 at a scan rate of 2 mV s-1, an impressive rate capability with 61% capacitance retention at 1 V s-1 and long cycle life. Moreover, the fabricated binder-free symmetric supercapacitor shows an ultrahigh volumetric energy density of 32.6 Wh L-1, which is among the highest values reported for carbon and MXene based materials in aqueous electrolytes. This work provides fundamental insight into the effect of interlayer spacing on the electrochemical performance of 2D hybrid materials and sheds light on the design of next-generation flexible, portable and highly integrated supercapacitors with high volumetric and rate performances. [ABSTRACT FROM AUTHOR]

Graphene sheets with a range of unusual properties and thermoplastic polyurethane ( TPU) were combined to modify polyvinyl chloride ( PVC), and the enhanced properties such as flexibility, thermal stability and mechanical properties of the PVC were investigated. In order to avoid the C − Cl bonds in PVC being weakened, graphene was incorporated into TPU in the melting state first and then this TPU was employed as a modifier to enhance and plasticize PVC in another melt blending step. In comparison with the ternary blending method, this step-by-step melt blending method was more efficient and convenient. The distribution of graphene sheets in the polymer matrix is uniform and no C − Cl bond weakened effect can be observed. Due to the similar polarity, TPU showed good compatibility with PVC and its plasticizing effect allowed a broader range of low temperature flexibility of the modified PVC matrix. Moreover, other properties of the resultant PVC matrix ( PTG- x) including mechanical properties, thermal stability and plasticizer migration resistance were all found to be improved. With innovative applications in mind, the development of new graphene-based materials will certainly lead to many future advances in science and technology. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Single‐layered and single‐crystalline graphene quantum dots (GQDs) are exfoliated from 2D conjugated polycycle compounds. The fluorescence properties of the GQDs are determined by the size of the precursors and are responsive to the pH of the GQDs solution. The synthesis method is novel and simple, and can be a general route to exfoliate 2D polycyclic compounds, including macrocyclic compounds, fused ring compounds, heterocyclic compounds and block molecules of 2D planar nanomaterials and polymers into single‐layered or single‐crystalline GQDs. [ABSTRACT FROM AUTHOR]

Molecular plasmonics explores and exploits the molecule-plasmon interactions on metal nanostructures to harness light at the nanoscale for nanophotonic spectroscopy and devices. With the functional molecules and polymers that change their structural, electrical, and/or optical properties in response to external stimuli such as electric fields and light, one can dynamically tune the plasmonic properties for enhanced or new applications, leading to a new research area known as active molecular plasmonics (AMP). Recent progress in molecular design, tailored synthesis, and self-assembly has enabled a variety of scenarios of plasmonic tuning for a broad range of AMP applications. Dimension (i.e., zero-, two-, and threedimensional) of the molecules on metal nanostructures has proved to be an effective indicator for defining the specific scenarios. In this review article, we focus on structuring the field of AMP based on the dimension of molecules and discussing the state of the art of AMP. Our perspective on the upcoming challenges and opportunities in the emerging field of AMP is also included. [ABSTRACT FROM AUTHOR]

Incorporation of conductive fillers into polymeric matrix to fabricate the composites with light-weight and excellent dielectric performance has been considered as one of the most promising processes. However, the inevitable high dielectric loss of the composites is still an obstacle for their practical applications, which has become a challenge for a long time, and the solution for this issue is still an open question. In this study, diglycidyl ether of bisphenol-A (DGEBA) molecules were used and grafted onto reduced graphene oxide (RGO) to synthesize DGEBA functionalized RGO (DGEBA-RGO). Various characterizations including TEM, FTIR, UV–visual spectrum, TGA, Raman spectrum and XRD revealed that the DGEBA molecules were grafted onto RGO sheets successfully. The DGEBA-RGO sheets were found to significantly improve the dielectric properties and thermal stability of epoxy compared to the corresponding graphene oxide (GO) and untreated RGO sheets. For instance, at 1 kHz, epoxy composites filled with 1.00 wt% DGEBA-RGO sheets showed a dielectric constant of ∼32 at room temperature, which is over 9 times higher than that of neat epoxy (∼3.5); meanwhile, the dielectric loss of the composites was suppressed and only 0.08. The enhanced dielectric properties can be well interpreted by the duplex interfacial polarization and the micro-capacitor model. The above outstanding properties should be ascribed to the well dispersion of DGEBA-RGO and the strong interaction between the filler and polymer matrix, which are induced by effective package of grafted DGEBA molecules on the graphene surface. [ABSTRACT FROM AUTHOR]

In this work, we investigate mechanical properties and fracture behaviors of thermally reduced graphene oxide (TRGO)-filled epoxy composites with two different dispersion/ interface levels. The amphiphilic surfactant treatment of TRGO was found to promote the dispersion in both water and epoxy, but also produced improved TRGO/epoxy interface. As expected, incorporation of untreated or treated TRGO sheets into epoxy increases the storage modulus and the glass transition temperature. In particular, significant improvements in both tensile strength and fracture toughness (KIC) of the TRGO/epoxy composites were also obtained after the surfactant treatment processing. For example, at a very low loading of 0.20 wt.-%, the surfactant-treated TRGO enhances the tensile strength and KIC of epoxy by ~51 and ~65%, respectively; while the corresponding untreated TRGO results in almost unchanged strength and produces ~52% improvement in the KIC value. Based on the fractography observation and analysis, several failure mechanisms, e.g., crack bridging, pull-out/debonding, and fracture of TRGO as well as matrix plastic deformation, were identified and correlated to the increased fracture toughness of the two composite systems studied. [ABSTRACT FROM AUTHOR]

The safe and efficient storage and release of hydrogen are widely recognized as the main challenges for the establishment of a fuel-cell-based hydrogen economy. Formic acid (FA) has great potential as a safe and convenient source of hydrogen for fuel cells. Despite tremendous efforts, the development of heterogeneous catalysts with high activity and relatively low cost remains a major challenge. The synthesis of AuPd-MnOx nanocomposite immobilized on ZIF-8-reduced-graphene-oxide (ZIF-8-rGO) bi-support by a wet-chemical method is reported here. Interestingly, the resultant AuPd-MnOx/ZIF-8-rGO shows excellent catalytic activity for the generation of hydrogen from FA, and the initial turnover frequency (TOF) reaches a highest value of 382.1 mol H2 mol catalyst−1 h−1 without any additive at 298 K. This good performance of AuPd-MnOx/ZIF-8-rGO results from the modified electronic structure of Pd in the AuPd-MnOx/ZIF-8-rGO composite, the small size and high dispersion of the AuPd-MnOx nanocomposite, and also the strong metal-support interaction between the AuPd-MnOx and ZIF-8-rGO bi-support. [ABSTRACT FROM AUTHOR]

Via a simple thermal stress assist process, the high-quality graphene was successfully obtained. The microstructure, morphology and the electrochemical performance of the as-prepared products were characterized by x-ray diffraction (XRD), field emission environment scanning electron microscope (SEM), Micro-Raman Spectroscopy System, element analysis system and LAND battery program-control test system respectively. The results show that the as-prepared products are uniform graphene nano-sheets (GNs) with large and smooth surface, and that the GNs, as an anode material for lithium-ion cell, exhibit good cyclic performance, which imply that the lithium ions and GNs have formed a relative stable structure to large degree. A possible form mechanism of the high-quality GNs is proposed. [ABSTRACT FROM PUBLISHER]

Terahertz radiation has uses in applications ranging from security to medicine. However, sensitive room-temperature detection of terahertz radiation is notoriously difficult. The hot-electron photothermoelectric effect in graphene is a promising detection mechanism; photoexcited carriers rapidly thermalize due to strong electron-electron interactions, but lose energy to the lattice more slowly. The electron temperature gradient drives electron diffusion, and asymmetry due to local gating or dissimilar contact metals produces a net current via the thermoelectric effect. Here, we demonstrate a graphene thermoelectric terahertz photodetector with sensitivity exceeding 10 V W-1 (700 V W-1) at room temperature and noise-equivalent power less than 1,100 pW Hz-1/2 (20 pW Hz-1/2), referenced to the incident (absorbed) power. This implies a performance that is competitive with the best room-temperature terahertz detectors for an optimally coupled device, and time-resolved measurements indicate that our graphene detector is eight to nine orders of magnitude faster than those. A simple model of the response, including contact asymmetries (resistance, work function and Fermi-energy pinning) reproduces the qualitative features of the data, and indicates that orders-of-magnitude sensitivity improvements are possible. [ABSTRACT FROM AUTHOR]

In this study, NaAlH 4 −based hydrogen storage materials with dopants were prepared by a two-steps in-situ ball milling method. The dopants adopted included Ce, few layer graphene (FLG), Ce + FLG, and CeH 2.51. The hydrogen storage materials were studied by non-isothermal and isothermal hydrogen desorption measurements, X-ray diffractions analysis, cycling sorption tests, and morphology analysis. The hydrogen storage performance of the as-prepared NaAlH 4 with Ce addition is much better than that with CeH 2.51 addition. This is due to that the impact of Ce occurs from the body to the surface of the materials. The addition of FLG further enhances the impact of Ce on the hydrogen storage performance of the materials. The hydrogen storage capacity, hydrogen sorption kinetics, and cycle performance of NaAlH 4 with Ce + FLG additions are all better than NaAlH 4 materials with the addition of either Ce or FLG alone. The NaAlH 4 with Ce and FLG addition starts to release hydrogen at 85 °C and achieves a capacity of 5.06 wt% after heated to 200 °C. The capacity maintains at 4.91 wt% (94.7% of the theoretical value) for up to 8 cycles. At 110 °C, the material can release isothermally a hydrogen capacity of 2.8 wt% within 2 h. The activation energies for the two hydrogen desorption steps of NaAlH 4 with Ce and FLG addition are estimated to be 106.99 and 125.91 kJ mol−1 H 2 , respectively. The related mechanisms were studied with first-principle and experimental methods. • A milling technique whose balls move in circle close to the inner jar wall was built. • Collision and adhesion of Al are avoided by ceramic jar and balls and graphene. • High concentration of V H , V Na , Ce defect and nonequilibrium vacancy were generated. • Co-addition of Ce and graphene enhance the hydrogen storage performance of NaAlH 4. • Particle refining by milling and confining effect by graphene were key points. [ABSTRACT FROM AUTHOR]

[Display omitted] Polymer materials containing C 6 rings and C O become promising electrode materials for high-performance lithium ion batteries (LIBs). However, the poor electronic conductivity severely restricts its further application. Herein, we design and construct a pyromellitic dianhydride anhydride anthraquinone/reduced graphene oxides (PMAQ/rGO-40) composite as an anode material for LIBs. The PMAQ is uniformly wrapped by conductive rGO nanosheets. The PMAQ/rGO-40 electrode without additional conductive agents displays a discharge capacity of 253 mAh g−1 over 3000 cycles under 2A g−1, which is higher than that of the PMAQ electrode with conductive agents. Meanwhile, a capacity of 196 mAh g−1 is achieved under 5A g−1. The enhanced cycling performance and rate ability are attributed to the rGO conductive network, which promotes electronic transport capability. In addition, the lithium ion storage mechanism and kinetics in the PMAQ/rGO-40 are investigated. The excellent electrochemical performance shows the potential application of the PMAQ/rGO composite anode material for high performance LIBs. [ABSTRACT FROM AUTHOR]

A rapid, facile, sensitive electrochemiluminescence sensor was fabricated based on a 3D graphene/CdSeTe/Ru(bpy) 3 2+ -doped silica nanocomposite modified electrode for the detection of folic acid (FA). 3D graphene which has the ability to enhance the intensity of electrochemiluminescence (ECL) was synthesized by a one-pot hydrothermal method. Then CdSeTe served as amplification elements were successively labeled on the layer of 3D graphene. In addition, per Ru(bpy) 3 2+ -doped silica nanoparticle encapsulated a great deal of Ru(bpy) 3 2+ , the ECL intensity has been further greatly enhanced. Importantly, the ECL signal on the 3D graphene/CdSeTe/Ru(bpy) 3 2+ -doped silica nanocomposite modified electrode was amplified by FA. The optimum detecting conditions were established by single-factor analysis and response surface multivariate optimization methodologies. Under the optimum conditions, the ECL intensity was well-proportional to logarithmic FA concentration range from 1.0 × 10 −11 M to 1.0 × 10 −6 M with the detect limit as low as 3.6 × 10 −12 M. In application to detect FA in drugs, the recoveries range from 95.0% to 97.5%, which indicates this sensor having potential application in folic acid analysis in real samples. [ABSTRACT FROM AUTHOR]

Potassium ion batteries or capacitors are a promising technology for large-scale energy storage due to the abundant resource and low cost of potassium. However, the development of stable electrode materials with high capacity, capable rate ability, and excellent cycling stability remains a challenge. Herein, carbon dots modified reduced graphene oxides (LAP-rGO-CDs) are designed and synthesized via a rapid and green microwave-assisted method with l -Ascorbic acid 6-palmitate (LAP) as the reducing agent. LAP-rGO-CDs present enlarged interlayer spacing and faster ion transfer rate owing to the introducing of carbon dots. Serving as a potassium ion battery electrode, LAP-rGO-CDs showed a high specific capacity of 299 mAh g−1 at 1 A g−1 and excellent cycling stability. Moreover, a LAP-rGO-CDs//AC full carbon-based potassium ion capacitor is assembled and displays a maximum energy density of 119 Wh kg−1 and a power density of 5352 W kg−1. This work demonstrates the potential application of LAP-rGO-CDs for high-performance potassium ion storage. [Display omitted] [ABSTRACT FROM AUTHOR]

Binary metal niobium oxides can offer a higher specific capacity compared to niobium pentoxide (Nb 2 O 5) and thus are ideal anode candidates for lithium ion capacitors (LICs). However, their lower electronic conductivity limits their ability to achieve high energy and power densities. In this paper, one-dimensional (1D) copper niobate (CuNb 2 O 6) nanowires are successfully prepared by electrospinning technology and then immobilized on two-dimensional (2D) reduced graphene oxide (rGO) nanosheets to form a unique 1D nanowire/2D nanosheet CuNb 2 O 6 /rGO structure. The 1D/2D CuNb 2 O 6 /rGO electrode exhibits a high specific capacity of 312.2 mAh g−1 at 100 mA g−1 as the anode of LICs. The proposed Li+ storage mechanism of the CuNb 2 O 6 anode involves CuNb 2 O 6 decomposition into lithium niobate (Li 3 NbO 4) and copper (Cu) during the initial lithium insertion process. The intercalation-type Li 3 NbO 4 will further serve as the host to Li+ and the inactive Cu phase will act as a conductive network for electron transportation. Furthermore, the energy density of the assembled CuNb 2 O 6 /rGO//activated carbon (CuNb 2 O 6 /rGO//AC) device could achieve a value as high as 92.1 Wh kg−1 and could thus be considered as a possible alternative electrode material for high energy and power LICs. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Unique nanostructure, high electrical conductivity, satisfactory energy density, and extraordinary cycling stability are important evaluation criteria for high-efficient energy storage devices. Herein, Fe 3 O 4 nanospheres are successfully in situ decorated on graphene nanosheets through an environmentally benign and facile solvothermal procedure. When utilized as an electrode for supercapacitor, the graphene/Fe 3 O 4 nanocomposite exhibits a notably enhanced specific capacity (268 F·g−1 at 2 mV·s−1) and remarkable cycling performance with 98.9% capacity retention after 10,000 cycles. Furthermore, the fabricated graphene/MnO 2 //graphene/Fe 3 O 4 asymmetric supercapacitor device displays a desirable energy density (87.6 Wh·kg−1) and superior cycling stability (93.1% capacity retention after 10,000 cycles). [ABSTRACT FROM AUTHOR]

We perform resonant Raman spectroscopy on 8° twisted bilayer graphene placed in an out-of-plane magnetic field. The high-quality device has narrow Landau level linewidth of less than 5 meV that enables detection of features from both electronic Raman scattering and magnetophonon resonance involving electronic transitions between the low energy Landau levels. Two magnetophonon resonances are observed, one at 4.6T in the strong coupling regime, and the other at 2.6T in the weak coupling regime. Using the measured Landau level transition energy, we analyze the renormalization of effective band velocity, whose dependence on magnetic field points to a 20% enhancement of dielectric constant due to the presence of an adjacent graphene layer, a quite prominent screening effect from a monolayer of carbon atoms in proximity. Both the Landau level transition electronic Raman and the magnetophonon resonance are gate tunable. Harnessing angular momentum conservation, we demonstrate charge tuning of electron phonon coupling strength for left and right circularly polarized G band phonons separately. • Van Hove singularities in twisted bilayer graphene enables resonant Raman scattering with infrared light excitation. • Twisted bilayer graphene exhibits enhanced screening effects and renormalized band velocity through Landau level spectroscopy. • Magnetophonon resonance in both strong and weak regimes are realized in the same high-quality twisted bilayer graphene sample. • Landau level transition and magnetophonon resonance in twisted graphene are gate tunable. [ABSTRACT FROM AUTHOR]

Molecular plasmonics explores and exploits the molecule–plasmon interactions on metal nanostructures to harness light at the nanoscale for nanophotonic spectroscopy and devices. With the functional molecules and polymers that change their structural, electrical, and/or optical properties in response to external stimuli such as electric fields and light, one can dynamically tune the plasmonic properties for enhanced or new applications, leading to a new research area known as active molecular plasmonics (AMP). Recent progress in molecular design, tailored synthesis, and self-assembly has enabled a variety of scenarios of plasmonic tuning for a broad range of AMP applications. Dimension (i.e., zero-, two-, and threedimensional) of the molecules on metal nanostructures has proved to be an effective indicator for defining the specific scenarios. In this review article, we focus on structuring the field of AMP based on the dimension of molecules and discussing the state of the art of AMP. Our perspective on the upcoming challenges and opportunities in the emerging field of AMP is also included.

In our work, the porous carbon nanosheets (PCNs) are successfully prepared using one-step activation and carbonization of the naturally hollow tube-like dandelion fluffs. The dandelion fluff with hollow tube structure is composed of aligned nanocellulose, enabling the facile activating agent (KOH) permeation, which can activate the dandelion fluff into porous interconnected carbon nanosheets. The obtained porous interconnected graphene-like structure of the activated carbon material contributes to the electrolyte permeation and electron transfer, which is beneficial to enhance the electrochemical performances, especially the rate capability. Manganese dioxide (MnO 2 ) modified PCNs composited with MnO 2 is prepared as the positive electrode for asymmetric supercapacitor using in-situ microwave deposition method. The conformally coated MnO 2 on PCNs can facilitate the ion diffusion and the electron transport, which contribute to the enhancement of the rate performance. Herein, the assembly asymmetric supercapacitor based on PCNs and MnO 2 /PCNs composite displays an energy density as high as 28.2 Wh kg −1 at the power density of 899.36 W kg −1 and a good capacitance retention of 89% after 10,000 cycles. These results present that the graphene-like cross-linked carbon material is a promising electrode material for high-efficiency electrochemical energy storage and conversion. [ABSTRACT FROM AUTHOR]

In this work, the feasibility of a novel sensitive electrochemiluminescence aptasensor for the detection of lysozyme using Ru(bpy) 3 2+ -Silica@Poly- L -lysine-Au (RuSiNPs@PLL-Au) nanocomposites labeling as an indicator was demonstrated. The substrate electrode of the aptasensor was prepared by depositing gold nanoparticles (AuNPs) on 3D graphene-modified electrode. The lysozyme binding aptamer (LBA) was attached to the 3D graphene/AuNPs electrode through gold-thiol affinity, hybridized with a complementary single-strand DNA (CDNA) of the lysozyme aptamer labeled by RuSiNPs@PLL-Au as an electrochemiluminescence intensity amplifier. Thanks to the synergistic amplification of the 3D graphene, the AuNPs and RuSiNPs@PLL-Au NPs linked to Ru(bpy) 3 2+ -ECL further enhanced the ECL intensity of the aptasensor. In presence of lysozyme, the CDNA segment of the self-assembled duplex was displaced by the lysozyme, resulting in decreased electrochemiluminescence signal. Under the optimized conditions, the decrease in electrochemiluminescence intensity varied proportionally with the logarithmic concentration of the lysozyme from 2.25 × 10 –12 to 5.0 × 10 −8 mol L −1 , and the detection limit was estimated to 7.5 × 10 –13 mol L −1 . The aptasensor was further tested in real samples and found reliable for the detection of lysozyme, thus holding great potential application in food safety researches and bioassay analysis. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) nanomaterials have attracted significant interest for supercapacitor applications due to their high surface to volume ratio. Layered 2D materials have the ability to intercalate ions and thus can provide intercalation pseudocapacitance. Properties such as achieving fast ion diffusion kinetics and maximizing the exposure of the electrolyte to the surface of the active material are critical for optimizing the performance of active materials for electrochemical capacitors ( i.e. Supercapacitors). In this study, two 2D materials, titanium carbide (Ti 3 C 2 T x ) and reduced graphene oxide (rGO), were used as electrode materials for asymmetric supercapacitors, with the resulting devices achieving high capacitance values and excellent capacitance retention in both aqueous and organic electrolytes. This work demonstrates that Ti 3 C 2 T x is a promising electrode material for flexible and high-performance energy storage devices. [ABSTRACT FROM AUTHOR]

Aqueous magnesium ion battery as a new energy storage system is always explored due to excellent properties with high theoretical specific capacity, low-cost and safe aqueous electrolytes. However, the study on available material as anode in aqueous magnesium ion battery is very limited, which is the main reason that the kinetics of multivalent magnesium ions deinserted from the host material is very difficult. In this work, the nanoneedle FeVO 4 ·0.9H 2 O as available anode material is prepared and further modified by compositing with graphene. The FeVO 4 ·0.9H 2 O/Graphene composite exhibits the more excellent electrochemical performance, for example, the initial discharge capacity of FeVO 4 ·0.9H 2 O/Graphene electrode at the current density of 50 mAh g −1 in 1.0 mol L −1 MgSO 4 electrolyte is 183.8 mAh g −1 , but that of the FeVO 4 ·0.9H 2 O is 150.3 mAh g −1 . Therefore, the aqueous magnesium ion full battery is successfully assembled by FeVO 4 ·0.9H 2 O/Graphene as anode, 1.0 mol L −1 MgSO 4 as electrolyte and Mg-OMS-1 as cathode, which can obtain the discharge capacity of 53.1 mAh g −1 at a current density by calculate the total mass of two electrodes and the a high energy density of 58.5 Wh kg −1 . [ABSTRACT FROM AUTHOR]

A novel strategy for confined synthesis of graphene wrapped nano-sized LiMn 0.5 Fe 0.5 PO 4 hybrid composite has been developed, including co-precipitation and solvothermal reactions. The LiMn 0.5 Fe 0.5 PO 4 nanoparticles with a constrained diameter of 20 nm are homogeneously wrapped by a continuous interconnected graphene sheets. The mechanism and composite structure evolution during the process are carefully investigated and discussed. With the shortened Li + diffusion paths and enhanced electron conductivity, the hybrid composite shows high discharge capacity and superior rate performance with the discharge capacities of 166 mA h g −1 at 0.1 C and 90 mA h g −1 at 20 C. Excellent cycle stability is also demonstrated with only about 7.8% capacity decay after 500 cycles at 1 C. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) graphene-based porous materials with a combination of low density, superelasticity, excellent mechanical resilience and tunable functionalities can be used in diverse applications. Here we report an approach of fabricating the stable and flexible 3D graphene aerogel materials with tunable functionality via a general silane-assisted processing that maintains an effective control of the chemistry, architecture and functionality of these porous structures. Simultaneous reduction and functionalization were achieved under both a low temperature and a low graphene oxide concentration in aqueous solution via using a facile one-step co-assembly method. The introduction of silane bonding tailors both the porous microstructure and the surface property of the lightweight aerogel effectively, subsequently providing improved mechanical properties and versatile functionalities including super compressive elasticity, outstanding cyclic resilient property, good electrical conductivity, stable viscoelastic properties, high level energy absorption capacity, excellent hydrophobicity, remarkable thermal stability and extremely high sensitivity of elasticity-dependent electrical conductivity. This opens up scalable and low-cost ways to the integration of microscopic two-dimensional graphene sheets into macroscopic 3D graphene aerogel materials, thus providing the possibility of fabricating novel lightweight porous aerogel materials with controllable functionalities and reversible compressibility for applications in numerous fields. [ABSTRACT FROM AUTHOR]

In this study, a three-dimensional (3D) graphene/ZnO nanorod (G/ZnO) composite was synthesized by chemical vapor deposition (CVD) and simple hydrothermal method. Integration of 3D graphene and ZnO nanorods leads to a high performance in photocatalytic degradation toward methyl orange (MO). The results indicate that the 3D G/ZnO composite achieves a higher degradation efficiency under UV light than pure ZnO nanorods. The enhancement of photocatalytic activity can be attributed to effective separation of photo-generated electrons and holes at the interface of graphene and ZnO. [ABSTRACT FROM AUTHOR]

In order to overcome the poor stability of polyaniline (PANI) and to improve the electrochemical performance based on graphene, MnO 2 and PANI ternary composite, graphene/MnO 2 /PANI nanorod arrays (GMPNAs) were fabricated firstly via synthesizing highly ordered MnO 2 /PANI coaxial nanorod arrays on graphene film, using a simple and controllable electrochemical technique. With the arrays structure and synergetic interaction between graphene, MnO 2 , and PANI, which not only can provide high interfacial area, short ion diffusion path, and fast electrical pathways, but also can reduce agglomeration of material in using process, the specific capacitance and cycling stability of GMPNAs were improved greatly compared to that of pure PANI and MnO 2 /PANI binary composite. The maximum specific capacitance of GMPNAs was as high as 755 F g −1 at a current density of 0.5 A g −1 and retained 87% of the initial capacitance after 1000 cycles. It is believed that the GMPNAs composite will have a great potential for application in supercapacitors and the design of microstructure of GMPNAs is extendable to other pseudocapacitive electrodes. [ABSTRACT FROM AUTHOR]

• Bimetallic (Ni,Mo)S 2 was synthesized through a two-step solvothermal approach. • The (Ni,Mo)S 2 /G composite exhibits high specific capacity of 951 C g−1. • The ASC device shows a ultrahigh energy density of 84.5 Wh kg−1. Thanks to their high electrical conductivity, electrochemical stability and activity, transition metal sulfides have been widely designed and developed for supercapacitors with excellent electrochemical performances. Herein, we report the NiS 2 /MoS 2 mixed phases with abundant exposed active edge sites decorated on graphene nanosheets (named as (Ni,Mo)S 2 /G) through a facile two-step hydrothermal approach. Benefitting from its unique chemical property and structure, the as-prepared (Ni,Mo)S 2 /G composite possesses impressive electrochemical performances as electrodes of battery-type supercapacitors in 2 M KOH, such as high specific capacity of 951 C g−1 (2379 F g−1) at 1 A g−1 with superb rate capability (60.7% at 100 A g−1). Additionally, the asymmetric supercapacitor (ASC) device assembled based on the active edge site-enriched (Ni,Mo)S 2 /G as positive electrode and nitrogen-doped porous graphene as negative electrode displays an ultrahigh energy density of 84.5 Wh kg−1, superior to those of the Ni- and Mo-based ASCs in aqueous electrolytes reported so far. Such novel strategy may hold great promise for exploring other polymetallic sulfides with abundant exposed active edge sites for energy storage and conversion. [ABSTRACT FROM AUTHOR]