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Flexible graphene‐based paper electrodes (FGPEs) are a new class of study and the research on this electrode material has been carried out for approximately ten years. FGPEs have many advantages compared to classical solid electrodes such as being flexible, foldable, adaptable to flexible electronics, being cut, easily shaped, and effective and adjustable modification. In this work, the applicability of FGPEs modified with polyindole (PIN) thin films and zinc oxide nanoparticles (ZnO‐NPs) to energy‐storage systems as a supercapattery design is presented, and especially the limitations of ZnO‐NPs for energy‐storage applications are revealed to inform researchers working for a similar purpose. Capacitance calculations have been performed using both cyclic voltammetry (CV) and galvanostatic charge‐discharge (GCD) experiments. It was observed that the rGO/PIN paper demonstrated almost 30 times more energy‐storage capacity than that of the rGO/PIN/ZnO paper due to the electrochemical instability of ZnO‐NPs on the flexible electrode platform at the applied potential region in 1.0 M HClO4 solution. The rGO/PIN paper with a highly flexible property exhibited an energy density of 74.5 W h cm−2 and a power density of 2258 W cm−2 at a current density of 2.2 mA cm−2, revealing hopeful results for future modular and flexible approaches. [ABSTRACT FROM AUTHOR]

The development of nanohybrid with high electrocatalytic activity is of great significance for electrochemical sensing applications. In this work, we develop a novel and facile method to prepare a high-performance flexible nanohybrid paper electrode, based on nitrogen-doped carbon (NC) wrapped Bi nanoparticles (Bi-NPs) assembly derived from Bi-MOF, which are decorated on a flexible and freestanding graphene paper (GP) electrode. The as-obtained Bi-NPs encapsulated by an NC layer are uniform, and the active sites are increased by introducing a nitrogen source while preparing Bi-MOF. Owing to the synergistic effect between the high conductivity of GP electrode and the highly efficient electrocatalytic activity of Bi-NPs, the NC wrapped Bi-NPs (Bi-NPs@NC) modified GP (Bi-NPs@NC/GP) electrode possesses high electrochemically active area, rapid electron-transfer capability, and good electrochemical stability. To demonstrate its outstanding functionality, the Bi-NPs@NC/GP electrode has been integrated into a handheld electrochemical sensor for detecting heavy metal ions. The result shows that Zn2+, Cd2+, and Pb2+ can be detected with extremely low detection limits, wide linear range, high sensitivity, as well as good selectivity. Furthermore, it demonstrates outstanding electrochemical sensing performance in the simultaneous detection of Zn2+, Cd2+, and Pb2+. Finally, the proposed electrochemical sensor has achieved excellent repeatability, reproducibility, stability, and reliability in measuring real water samples, which will have great potential in advanced applications in environmental systems. [ABSTRACT FROM AUTHOR]

The present study reports the fabrication of reduced graphene oxide (rGO)/gold nanoparticles (AuNP) nanocomposites modified cellulose fiber paper‐based electrochemical biosensor for procalcitonin (PCT) biomarker detection. PCT is a biomarker specific for bacterial infection (BI) detection and has gained much attention as a potential solution to the problems associated with determining appropriate antibiotic use. In sepsis and other severe infections, serum PCT levels increase to values above 100 ng mL−1 in response to pro‐inflammatory stimulation. The structural and morphological characterization of the rGO‐AuNP composite are investigated using UV‐Vis spectroscopy, FTIR spectroscopy, X‐ray diffraction, and scanning electron microscopy. Monoclonal antibodies specific to PCT were covalently immobilized onto the rGO‐AuNP nanocomposite modified paper to fabricate an electrochemical biosensor. The fabricated biosensor exhibits linearity in the PCT concentration range 10 −15×103 pg mL−1, with a low detection limit 10 pg mL−1. Furthermore, the proposed biosensor also exhibited good selectivity and could detect PCT biomarkers even in the presence of other interfering electroactive species such as glucose, oxalic acid, and urea. The proposed CF‐based biosensor has been proven as an accelerated simple point‐of‐care (POC) exploratory approach for early PCT diagnosis in inadequate areas with limited production facilities, computational techniques, and highly skilled experts. [ABSTRACT FROM AUTHOR]

Herein, we prepared a bisuppport‐based bimetallic nanoparticle composite AuFe/ZIF‐8‐graphene. It exhibited high peroxidase activity compared to those hybrids without graphene support, which demonstrated the regulatory effect of graphene on the catalytic activity. SEM, TEM, EDX, XRD, FT‐IR and XPS characterization showed that Au and Fe3O4 NPs were successfully immobilized on ZIF‐8‐rGO carriers. Kinetic analysis confirmed that the fabricated composites showed better Km and Vmax for H2O2 than HRP and some other reported peroxidase mimics. Under the optimal conditions, a sensing assay for H2O2 determination was constructed with a linear detection range of 0.01–2.5 mM and a detection limit of 0.63 μM. On this basis, a colorimetric test paper with its standard card was prepared for rapid visualization detection. It realized H2O2 detection in the range of 0.01‐500 mM and was further successfully applicated in the semi‐quantitative detection of H2O2 in actual spiked water samples. This achievement was expected to encourage the development of rapid visual detection for other pollutants in environmental and medical field. [ABSTRACT FROM AUTHOR]

• GNP and MWCNT collectively affect mechanical stability and electrical property of the PFHD. • Optimized PFHD contains 67 wt% MWCNT and 33 wt% GNT. • Paper-based low cost and rapid heating device shows a T max of 116.3 ℃ at 2.5 V. • Flexible and lightweight heating device ideal for PEMFC driven aerial vehicle can serve as a disposable container for hydrogen fuel. A paper-based flexible heating device (PFHD - paper-based flexible heating device) composed of a cellulose paper substrate and a carbonaceous functional electrode is reported. The functional composite electrodes containing graphene nanoplatelets (GNP - graphene nanoplatelets) and multi-walled carbon nanotubes (MWCNT) in various compositional ratios were prepared by dip-coating the oxygen plasma-treated paper substrate into the composite ink, and subsequently dried at 110 ℃ for 30 min to prepare PFHDs. The electrochemical characteristics and heat generation properties of PFHDs indicated that the GNP component in the functional electrode enhanced the electrical conductivity of the electrode, and the physical stability was enhanced mainly by the MWCNT component. Accordingly, PFHD 0.33 which contains 33 % GNP and 67 % MWCNT in the functional electrode shows excellent heating performance with high stability and areal rated power of 0.68 W cm−2 (specific rated power = 45 W g−1). The measured sensitivity of PFHD 0.33 is 31.50 ℃ V−1 at the applied DC voltage of 0.1–2.0 V. [Display omitted] [ABSTRACT FROM AUTHOR]

The flexible electrodes are the crucial components for fabricating wearable supercapacitors. In this study, we present a quick and convenient method to prepare graphene paper (GP) as a flexible current collector on a large scale by an easy one‐step method. The composite electrode integrated with GP and MnO2 as a flexible supercapacitor was obtained by an electrochemical deposition method without using binder or conductive agent. The substrate (GP) of electrode not only provides mechanical strength, but also contributes energy storage capacity. The MnO2 nanoparticles deposited on the surface of GP further improved the electrochemical performance of composite. The neat GP can give a specific capacitance of 184 F/g at a current density of 1 A/g. At a current density of 1 A/g, the specific capacitance of the GP/MnO2 composite with a deposition time of 30 s is as high as 410 F/g. The method presented here shows great potential for the development of flexible electrode materials in practical energy storage devices. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this article is to prepare graphene/polyimide composite materials for use as bearing cage materials, improving the friction and wear performance of bearing cages. Design/methodology/approach: The oil absorption and discharge tests were conducted to evaluate the oil content properties of the materials, while the mechanical properties were analyzed through cross-sectional morphology examination. Investigation into the tribological behavior and wear mechanisms encompassed characterization and analysis of wear trace morphology in PPI-based materials. Consequently, the influence of varied graphene nanoplatelets (GN) concentrations on the oil content, mechanical and tribological properties of PPI-based materials was elucidated. Findings: The composites exhibit excellent oil-containing properties due to the increased porosity of PPI-GN composites. The robust formation of covalent bonds between GN and PPI amplifies the adhesive potency of the PPI-GN composites, thereby inducing a substantial enhancement in impact strength. Notably, the PPI-GN composites showed enhanced lubrication properties compared to PPI, which was particularly evident at a GN content of 0.5 Wt.%, as evidenced by the minimization of the average coefficient of friction and the width of the abrasion marks. Practical implications: This paper includes implications for elucidating the wear mechanism of the polyimide composites under frictional wear conditions and then to guide the optimization of oil content and tribological properties of polyimide bearing cage materials. Originality/value: In this paper, homogeneously dispersed PPI-GN composites were effectively synthesized by introducing GN into a polyimide matrix through in situ polymerization, and the lubrication mechanism of the PPI composites was compared with that of the PPI-GN composites to illustrate the composites' superiority. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2023-0415 [ABSTRACT FROM AUTHOR]

A foldable array of patterned graphene/ZnO nanoparticle UV sensor and asymmetric micro-supercapacitors (AMSCs) integrated on a paper substrate with patterned liquid metal interconnections is reported. The resistor type UV sensor based on graphene/ZnO nanoparticles is patterned to be driven by the stored energy of the integrated AMSCs. The AMSC consists of MnO2 nanoball deposited multiwalled carbon nanotubes (MWNTs) and V2O5 wrapped MWNTs as positive and negative electrodes, respectively. As an electrolyte, propylene carbonate-poly(methyl methacrylate)-LiClO4, an organic solvent-based gel, is used. The UV sensor and AMSCs can be easily integrated on a liquid metal, Galinstan, patterned, waterproof mineral paper and show a mechanically stable UV sensing, regardless of repetitive folding cycles. This work demonstrates a novel foldable nanomaterial based sensor system driven by integrated energy storage devices, applicable to future wearable and portable electronics. [ABSTRACT FROM AUTHOR]

A facile strategy is designed for the fabrication of flexible and free-standing ternary CoSnO 3 /graphene/carbon nanotubes (CoSnO 3 /GN/CNTs) composite papers through a simple filtration, followed by annealing process. The CoSnO 3 /GN/CNTs composite papers with high flexibility and tailorability can be easily fabricated. The CoSn(OH) 6 nanoparticles/graphene oxide/carbon nanotubes (CoSn(OH) 6 /GO/CNTs) composite papers obtained by a simple filtration method are transformed into CoSnO 3 /GN/CNTs composite papers after a thermal treatment process. In this unique composite structure, CoSnO 3 nanoparticles (nanocubes and nanoboxes) are embedded homogenously into the 3D framework of graphene and carbon nanotubes, respectively, in which offers not only a 3D conductive network and a dual restriction on the aggregation of CoSnO 3 nanoparticles, but also accommodates the large volume expansion of CoSnO 3 nanoparticles. When used directly as binder- and conductive agent-free anodes for lithium-ion batteries, the CoSnO 3 /GN/CNTs composite papers exhibit superb electrochemical properties including extraordinary reversible capacities, superior rate capabilities and stable cycle performances compared to CoSnO 3 nanoparticles and GN/CNTs paper, suggesting a new pathway for the rational engineering of anode materials. [ABSTRACT FROM AUTHOR]

This paper demonstrates, for the first time, the use of paper-based electrochemical devices coupled to external solid working electrodes. The paper-based electrochemical cells were fabricated using inexpensive and largely available office paper, according to a simple protocol that consists on the creation of hydrophobic barriers using paraffinized paper and preheated metal stamp. The counter and reference electrodes were integrated to the paper platform through the deposition of carbon and silver inks, respectively. The electrochemical paper analytical device (ePAD) was coupled to external glassy carbon rod electrode modified with reduced graphene oxide doped with Cu nanoparticles through meniscus configuration. The analytical usefulness of this electrochemical approach was demonstrated through the simultaneous determination of paracetamol and caffeine in biological samples. The analytes were successfully quantified in real urine samples and limits of detection of 24.6 nM (paracetamol) and 36.1 nM (caffeine) were obtained. The paper platform showed good stability (RSD of 1.07 % for the peak currents and 1.43 % for the peak potentials) and satisfactory performance. The use of solid electrodes coupled to paper electrochemical devices, firstly demonstrated here, opens new possibilities for the utilization of ePADs in electrochemistry and electroanalytical chemistry and offers advantages such as the extremely reduced consumption of reagents and the minimal generation of wastes. [ABSTRACT FROM AUTHOR]

A single-step laser scribing process is used to pattern nanostructured electrodes on paper-based devices. The facile and low-cost technique eliminates the need for chemical reagents or controlled conditions. This process involves the use of a CO2 laser to pyrolyze the surface of the paperboard, producing a conductive porous non-graphitizing carbon material composed of graphene sheets and composites with aluminosilicate nanoparticles. The new electrode material was extensively characterized, and it exhibits high conductivity and an enhanced active/geometric area ratio; it is thus well-suited for electrochemical purposes. As a proof-of-concept, the devices were successfully employed for different analytical applications in the clinical, pharmaceutical, food, and forensic fields. The scalable and green fabrication method associated with the features of the new material is highly promising for the development of portable electrochemical devices. [ABSTRACT FROM AUTHOR]

Graphene-based all-solid-state supercapacitors (ASSSCs) have received increasing attention. It’s a great challenge to fabricate high-performance flexible solid-state supercapacitors with high areal and volumetric energy storage capability, superior electron and ion conductivity, robust mechanical flexibility, as well as long term stability. Herein, we report a facile method to fabricate flexible ASSSCs based on densely-packed reduced graphene oxide (rGO)/polypyrrole nanoparticle (PPy NP) hybrid papers with a sandwich framework, which consists of well-separated and continuously-aligned rGO sheets. The incorporation of PPy NPs not only provides pseudocapacitance but also facilitates the infiltration of gel electrolyte. The assembled ASSSCs possess maximum areal and volumetric specific capacitances of 477 mF/cm 2 and 94.9 F/cm 3 at 0.5 mA/cm 2 . They also exhibit little capacitance deviation under different bending states, excellent cycling stability, small leakage current and low self-discharge characteristics. Additionally, the maximum areal and volumetric energy densities of 132.5 μWh/cm 2 and 26.4 mWh/cm 3 are achieved, which indicate that this hybrid paper is a promising candidate for high-performance flexible energy storage devices. [ABSTRACT FROM AUTHOR]

Graphene-based all-solid-state supercapacitors (ASSSCs) are one of the most ideal candidates for high-performance flexible power sources. The achievement of high volumetric energy density is highly desired for practical application of this type of ASSSCs. Here, we present a facile method to boost volumetric performances of graphene-based flexible ASSSCs through incorporation of ultrafine polyaniline-poly(4-styrenesulfonate) (PANI-PSS) nanoparticles in reduced graphene oxide (rGO) papers. A compact structure is obtained via intimate contact and π–π interaction between PANI-PSS nanoparticles and rGO sheets. The hybrid paper electrode with the film thickness of 13.5 μm, shows an extremely high volumetric specific capacitance of 272 F/cm 3 (0.37 A/cm 3 in a three-electrode cell). The assembled ASSSCs show a large volumetric specific capacitance of 217 F/cm 3 (0.37 A/cm 3 in a two-electrode cell), high volumetric energy and power density, excellent capacitance stability, small leakage current as well as low self-discharge characteristics, revealing the usefulness of this robust hybrid paper for high-performance flexible energy storage devices. [ABSTRACT FROM AUTHOR]

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 increasing demands for portable, wearable, and implantable sensing devices have stimulated growing interest in innovative electrode materials. In this work, we have demonstrated that printing a conductive ink formulated by blending three-dimensional (3D) porous graphene–carbon nanotube (CNT) assembly with ionic liquid (IL) on two-dimensional (2D) graphene paper (GP), leads to a freestanding GP supported graphene–CNT–IL nanocomposite (graphene–CNT–IL/GP). The incorporation of highly conductive CNTs into graphene assembly effectively increases its surface area and improves its electrical and mechanical properties. The graphene–CNT–IL/GP, as freestanding and flexible substrates, allows for efficient loading of PtAu alloy nanoparticles by means of ultrasonic-electrochemical deposition. Owing to the synergistic effect of PtAu alloy nanoparticles, 3D porous graphene–CNT scaffold, IL binder and 2D flexible GP substrate, the resultant lightweight nanohybrid paper electrode exhibits excellent sensing performances in nonenzymatic electrochemical detection of glucose in terms of sensitivity, selectivity, reproducibility and mechanical properties. [ABSTRACT FROM AUTHOR]

Among different inorganic and organic polarizer elements, thin-film light polarizers occupy a special place because of their flexibility, ease of integration into any optoelectronic circuit, and good functioning in the visible and near-infrared spectral range and can compete with Glan and Nicolas volumetric prisms. This paper presents the results of a study on how carbon-based nanoparticles influence on the basic properties of a well-known PVA-based polymer matrix, using which it is possible to obtain good transparency for parallel light components. An accent is made on graphene oxide nanoparticles, which are used as PVA sensitizers. It was shown for the first time that the structuring of PVA with graphene oxides allows an increased transmittance of the parallel light component to be obtained, saving the transmittance of the orthogonal one. Moreover, the graphene network can increase the mechanical strength of such thin-film PVA-based polarizers and provoke a change in the wetting angle. These advantages make it possible to use graphene oxide-structured thin-film light polarizers based on a PVA matrix as an independent optoelectronic element. Some comparative results for polarizers based on PVA-C70 structures are shown as well. [ABSTRACT FROM AUTHOR]

In engineering measurements, metal foil strain gauges suffer from a limited range and low sensitivity, necessitating the development of flexible sensors to fill the gap. This paper presents a flexible, high-performance piezoresistive sensor using a composite consisting of graphene nanoplatelets (GNPs) and polydimethylsiloxane (PDMS). The proposed sensor demonstrated a significantly wider range (97%) and higher gauge factor (GF) (6.3), effectively addressing the shortcomings of traditional strain gauges. The microstructure of the GNPs/PDMS composite was observed using a scanning electron microscope, and the distribution of the conductive network was analyzed. The mechanical behavior of the sensor encapsulation was analyzed, leading to the determination of the mechanisms influencing encapsulation. Experiments based on a standard equal-strength beam were conducted to investigate the influence of the base and coating dimensions of the sensor. The results indicated that reducing the base thickness and increasing the coating length both contributed to the enhancement of the sensor's performance. These findings provide valuable guidance for future development and design of flexible sensors. [ABSTRACT FROM AUTHOR]

• Graphene coated on paper through a facile dip-coating and vacuum filtration method. • Humidity sensor showed high response (290 %) and excellent sensitivity (3.5 kΩ/%RH). • Piezoresistive sensor showed unique response at different loads. Highly sensitive and fast-responding humidity and piezoresistive sensor was fabricated based on cellulose paper coated with graphene (CGN), which were synthesized via dip-coating (D-CGN) and vacuum filtration method (V-CGN). CGN showed excellent electrical properties and SEM images confirmed that graphene nanoplatelets were held tightly between the pores of the paper. V-CGN based sensor displayed excellent sensitivity and fast response to the humidity change at room temperature. The highest response of 75 % and 290 % was achieved for D-CGN and V-CGN based sensor, respectively. In addition, both the sensors exhibited fast response and recovery along with excellent repeatability characteristics. Besides, both the sensors displayed excellent piezoresistive performance. The highest piezoresistive response of 125 % and 250 % for D-CGN and V-CGN was achieved. Cellulose paper with low cost, lightweight and biocompatibility combined with graphene could be a promising material for smart, wearable electronic devices. [ABSTRACT FROM AUTHOR]

Conductive polymer composites require high conductive filler loadings to achieve relatively ideal electromagnetic interference (EMI) shielding performance, which brings problems such as heavy weight and poor processability and ultimately limits their application in the aerospace field. To solve the above problems and realize the preparation of excellent EMI shielding composites with low filler loadings, a bipolar pulsed electric field-induced graphene nanoplatelets (GNPs) alignment method is proposed in this paper to improve the electrical conductivity and EMI shielding performance. The orientation and alignment of GNPs in the matrix were characterized by x-ray diffraction and scanning electron microscopy, and the results showed that GNPs formed a conductive network. The electrical conductivity of the composite material in the X-band was measured, and the results showed that the bipolar pulsed electric field could significantly improve the electrical conductivity of the composite material; the improvement percentage reached 100%–300% under the five filler loadings. In addition, the EMI shielding effectiveness of the composite material in the X-band was tested. The results showed that the EMI shielding effectiveness of the composite material with a mass fraction of 14% increased from 16.48–15.86 dB to 21.37–20.99 dB with the action of the bipolar pulsed electric field, and the improvement percentage was 32%. This is the first study on improving the EMI shielding performance of composite materials by applying a bipolar pulsed electric field, and it provides an effective method to prepare EMI shielding composites with low filler loadings. [ABSTRACT FROM AUTHOR]

This document is a correction notice for a scientific paper titled "Nonequilibrium Casimir-Polder Interaction between Nanoparticles and Substrates Coated with Gapped Graphene." The authors provide two corrections to their paper. The first correction involves replacing Equation (28) in the paper with a corrected version that includes an additional term. This correction affects Figures 5 and 6 in the paper. The second correction involves revising the wording in Section 4 of the paper. The authors state that these corrections do not impact the main results or conclusions of the paper. The corrected figures are provided in the notice. [Extracted from the article]

This paper conducts modeling and vibration analysis of a spinning cylindrical shell attached with a beam, namely, an assembled cylindrical shell-beam structure, which is reinforced by graphene nanoplatelets (GPLs). The available performance attributes of the beam and cylindrical shell, determined by the Halpin-Tsai model together with the rule of mixture, are deemed to change continuously along their thickness directions. In accordance to the Euler-Bernoulli beam theory and the Donnell's shell theory, the Lagrange's equation is applied to obtain the coupled governing equations of the assembly. Besides, the substructure modal synthesis method is used to acquire vibration behaviors of the nanocomposite assembled shell-beam structure. The influences of the graphene nanoplatelet (GPL) distribution pattern, GPL weight fraction, length-to-width ratio and length-to-thickness ratio of GPLs, and spinning speed on the vibration performance of the assembled shell-beam structure. The findings could provide an important light on the design of coupled nanocomposite cylindrical shell-beam assembly for outstanding mechanical performance. [ABSTRACT FROM AUTHOR]

The nonlinear vibration analysis of functionally graded reinforced with graphene platelet (FG-GRC) porous truncated conical shells surrounded by the Winkler-Pasternak elastic foundation is presented in this paper. An improved model for evaluating the material properties of porous composites is proposed. Three types of porous distribution and three patterns of graphene nanoplatelets (GPLs) dispersion are estimated. Coupled with the effect of the Winkler-Pasternak elastic foundation, the nonlinear governing equations are developed by using the Hamilton principle. The Galerkin integrated technique is employed to obtain the linear and nonlinear frequencies of the shells. After the present method is validated, the effects of the pores, GPLs, the Winkler-Pasternak foundation, and the semi-vertex are investigated in detail. The results show that the linear frequency can be raised by increasing the values of the mass volume of the GPL and foundation parameters. In contrast, the ratio of nonlinear to linear frequency declines as the mass volume of the GPLs and foundation parameters rises. Furthermore, it is found that the minimum ratio of nonlinear to linear frequency can be obtained as the semi-vertex angle is about 55º, and the effect of porosity distribution on the linear and linear frequencies might be neglected. [ABSTRACT FROM AUTHOR]

The H 2 production from water-splitting and dehydrogenation of waste alcohols is widely investigated in current years to find out greener, and more efficient photocatalyst materials. Reduced graphene oxide (rGO; 1-10 wt%) coated TiO 2 and Ag(1 wt%)-TiO 2 core-shell nanocomposites are fabricated for enhanced photocatalytic H 2 production from H 2 O-splitting and CH 3 OH-dehydrogenation under UV irradiation. These rGO@TiO 2 and rGO@Ag–TiO 2 catalysts are characterized by XRD, Raman, FE-SEM, HR-TEM, XPS, BET, CV, EDS-mapping, PL, and UV–vis DRS for morphological, structural, and optical properties. After rGO(1-3 wt%) coating over TiO 2 , the H 2 amount is increased from 5 to 14 mmol for H 2 O-splitting and 13–83 mmol via CH 3 OH-dehydrogenation during 5 h UV irradiation, respectively. Due to the synergetic effect of rGO and Ag, core-shell rGO(2-4 wt%) coated Ag–TiO 2 produced the highest amount of 108–133 mmol of H 2 from water-splitting and 440–450 mmol from CH 3 OH-dehydrogenation during 7 and 5 h UV irradiation, respectively. The work illustrates the potential of Ag-deposition and rGO-coating over TiO 2 for efficient H 2 production. This paper reports the high photocatalytic activity of core-shell rGO@Ag–TiO 2 nanostructure for improved H 2 production (∼14 mmol/h) via water splitting and (∼90 mmol/h) via dehydrogenation of methanol under 5 h UV light irradiation. [Display omitted] • Core-shell nanostructure of rGO@TiO 2 and rGO@Ag–TiO 2 are fabricated. • rGO coating and Ag deposition highly improved the photocatalytic activity of TiO 2. • rGO@Ag–TiO 2 displayed superior photoactivity than rGO@TiO 2 nanocatalyst. • Highest amount of H 2 gas is photogenerated by rGO@Ag–TiO 2 photocatalysts. • Efficient H 2 O splitting and CH 3 OH dehydrogenation by rGO@Ag–TiO 2 composite. [ABSTRACT FROM AUTHOR]

Manipulation of nanoparticles by light induced forces is widely used in nanotechnology and bioengineering. In normal cases, when a nanoparticle is illuminated by light waves, the transfer of momentum from light to the nanoparticle can push it to move along the light propagation direction. On the other hand, the lateral optical force can transport an object perpendicular to the light propagation direction, and the optical pulling force can attract an object toward the light source. Although these optical forces have drawn growing attention, in situ tuning of them is rarely explored. In this paper, tuning of both lateral optical forces and optical pulling forces is numerically demonstrated via a graphene/α‐phase molybdenum trioxide (α‐MoO3) bilayer structure. Under plane‐wave illumination, both the amplitude and direction of the optical forces exerted on a nanoparticle above this bilayer structure can be tuned in the mid‐infrared range. The underlying mechanism can be understood by studying the corresponding isofrequency contours of the hybrid plasmon‐phonon polaritons supported by the graphene/α‐MoO3 bilayer. The analytical study using the dipole approximation method reproduces the numerical results, revealing the origin of the optical forces. This work opens a new avenue for engineering optical forces to manipulate various objects optically. [ABSTRACT FROM AUTHOR]

Graphene oxide is one of the latest in- trend nanomaterials in the field of nanotechnology which is being studied in various engineering fields. Yet, its effects on the transformer solid insulation remain unexplored. In this research, the transformer pressboard and Kraft paper are impregnated with nonconductive graphene oxide dispersed vegetable ester-based insulating nanofluid and the behavior of impregnated solid insulation is studied under different thermal aging conditions. The results show that after 60 days of aging, the crystallinity of nanofluid impregnated pressboard is 24.9% more than that of the base oil-blend (OB) impregnated pressboard whereas the crystallinity of nanofluid impregnated Kraft paper is 3.8% more than that of the base OB impregnated Kraft paper. In terms of dielectric properties, the ac breakdown voltage (BDV) of nanofluid impregnated pressboard and Kraft paper is 29.5% and 41% more than the OB impregnated pressboard and Kraft paper, respectively. The dielectric stress is more uniform in nanofluid-based insulation system as compared to the base OB-based insulation system leading to a better design clearance. Therefore, graphene oxide dispersed ester oil (EO)-based nanofluid impregnated solid insulation has better mechanical and dielectric properties, thus leading to an increased lifespan of the transformer. [ABSTRACT FROM AUTHOR]

The article presents information on the composites of silicon nanoparticles that are highly dispersed in the graphene sheets aid in the storage capacities and cycling stability of lithium ion batteries. The graphene sheets are supported by a three-dimensional (3-D) network of graphite that is formed by the reconstitution of the regions of graphene stacks. Information on conducting the silicon structure with a carbonaceous layer is also presented.

Aluminum nitride (AlN) is the material of choice for high power modulus substrates. The thermal and electrical conductions can be also fostered by adding CaF 2 and carbon particles, respectively. Moreover, additives (Y 2 O 3) have to be used as sintering aids to achieve full densification. In this paper, we report on tuning the electrical conduction within AlN-based composites developed by incorporating graphene nanoplatelets GNP, obtained from graphite exfoliation, in the AlN-based ceramics comprising Y 2 O 3 and CaF 2. These composites were prepared by Spark Plasma Sintering through a new configuration called "multiple preparation" with a view to fabricating three samples per cycle, revealing time and energy savings. An increase of the electrical conductivity by 10 orders of magnitude was obtained for these composites compared to the commercial AlN by adjusting the amount of GNP and the way of exfoliation. This work promotes the development of novel multifunctional ceramic composites for Power Electronics applications. [ABSTRACT FROM AUTHOR]

The aim of this research is to obtain collagene nanocomposites based on graphene, graphene oxide, GO, zinc oxide and metal nanoparticles and to evaluate their pro-, antioxidant and biological activities by luminescent and standard microbiological assays. The antimicrobial activity of graphene composites with added nanosized zinc oxide, silver and copper nanoparticles was tested on Firmicutes bacteria Staphylococcus epidermidis (ATCC 1228) and Gracillicutes Escherichia coli (ATCC 25922). The method of diffusion in agar was used in three variants - spot diffusion, well and paper-disc diffusion. The spot and diffusion disc approaches of the method have shown better effect than the well diffusion for testing the effect of graphene composites on bacteria. The composites with high ZnO content had the best antimicrobial properties against the tested bacteria. The cytotoxicity of the nanocomposites using normal MDCK and A549 epithelial sarcoma cells were tested for 24 h at a concentration of 100 mg mL-1. Cancer cells were found to be more sensitive than normal to the graphene composites, proving antitumor activity. The pro- and antioxidant effects of the tested nanomaterials depend on the pH level. At physiological conditions, in the Fenton's system, all but RGO+Cu do not appear to be suitable as an implant nanomaterial. In the H2O2 oxidation system all materials present stable antioxidant effects; only ZnO+RGO+Cu is close to control prooxidant levels. When the nanomaterials are tested for oxidation by O2.- radicals, ZnO+RGO and Zn+RGO+Cu show prooxidant effects, as the prooxidant activity is kept for ZnO+RGO even at physiological acidity pH 7.4. [ABSTRACT FROM AUTHOR]

The size-dependent bending and free vibration of bi-directional functionally graded graphene nanoplatelets reinforced composite (BDFG-GPLRC) microbeams are investigated based on the Timoshenko beam theory and isogeometric analysis (IGA). The modified couple stress theory (MCST) is employed to describe the scale effect of microbeams. GPLs are distributed as power functions along the thickness and axis directions and four types of distribution patterns are taken into account. Employing the minimum potential energy principle and Hamilton's principle, the government equations are established and solved by IGA. Correctness and accuracy of this method are verified by comparing with a published paper. By means of several numerical examples, the effects of GPL weight fraction, power-law indexes, boundary conditions and scale parameter on bending and free vibration behaviors of BDFG-GPLRC microbeams are studied in detail. [ABSTRACT FROM AUTHOR]

The nanoporous graphene papers (NGPs) was prepared by the hard-template method. The Pt−Pd modified NGPs hybrid was prepared by the self-assembly method. Then a glassy carbon electrode (GCE) modified with Pt−Pd bimetallic nanoparticles-functionalized nanoporous graphene composite has been prepared for the electrochemical determination of Xanthine (XA). The Pt−Pd/NGPs hybrid was characterized by transmission electron microscopy, scanning electron microscope and X-ray diffraction. The electrochemical behavior of XA on Pt−Pd/NGPs/GCE was investigated by cyclic voltammetry and amperometric i-t. The Pt−Pd/NGPs modified electrode exhibited remarkably electrocatalytic activity towards the oxidation reaction of XA in phosphate buffer solution (pH=5.5). Under the optimal conditions, the determination of XA was accomplished by using amperometric i-t, the linear response range from 1.0×10−5∼1.2×10−4 M. The detection limit was 3.0×10−6 M (S/N=3). The proposed modified electrode showed good sensitivity, selectivity, and stability with applied to determine XA in human urine. [ABSTRACT FROM AUTHOR]

The review presents the results of modeling of the solvation of nanoparticles with deep eutectic solvents that act as stabilizers of metal nanoparticles, which provide a new platform for nanoparticle technology. It is calculated that there is a slower dynamics of solvent molecules, i.e., a slowing down of water near solutes. Such water has limited movement and cannot be organized into tetrahedral forms, in contrast to water in volume. Also, the paper describes systematic studies of the adsorption configuration, distribution density and adsorption energy of molecules H$_{2}$O, CO$_{2}$, CH$_{4}$, N$_{2}$, C$_{8}$H$_{18}$ and fluorocarbons C$_{3}$F$_{8}$ and C$_{5}$F$_{12}$ on the surface of kaolinite (0 0 1). Water adsorption is initiated and occurs due to the growth of clusters around surface groups, which is mainly regulated by the interactions of hydrogen bonds. Further, the paper investigates theoretically physical and mechanical properties of nanoscale systems, in particular, nanotips, amorphous carbon monolayer and nanoparticles. It is shown that the single-layer amorphous carbon is surprisingly stable and is deformed with a high ultimate strength without the propagation of cracks from the point of failure. The sliding on amorphous polyethylene and silicon studied using the method of molecular dynamics is described. The paper also discusses the dependencies of the friction force, acting on nanoparticles, on their velocity and sizes, in particular, the contact area, the structure and the type of the material, as well as on the direction of their shear and temperature. At an angle of rotation $ 45^\circ $, the silicon friction forces reach a minimum value, which can be termed superlubricity. The molecular dynamics modeling of the surface of carbon nanotubes, chitosan, polyvinyl acetate, titanium dioxide, $α$-quartz and zeolite is described to solve application problems ranging from reaction control to targeted delivery and creation of new drugs. The general principles have been identified that artificial water channels made of carbon nanotubes porins must satisfy, which can serve as a basis for further experiments. The organic modification mainly forms a modifier layer by crosslinking the hydrogen bond with the substrate, the flatness of the modified layer is strongly influenced by the type and concentration of the modifier. [ABSTRACT FROM AUTHOR]

Air pollution is known as one of the most important causes of death in the whole world. Therefore, pollution reduction to achieve clean air was noticed by everyone. This way, using nanotechnology to control air and monitor is a novel approach. This paper investigates the effect of the number of graphene nano-pores on the SiO 2 separation from the H 2 O vapour in the presence of an external electric field with the magnitude of 0.01 V/Å using the molecular dynamics (MD) method. The electric field affects the charged particles and causes disturbance in the structure. It also prevents SiO 2 nanoparticles from passing through the graphene nanosheet. Also, the presence of carbon nanosheets acts as a membrane and affects the diffusion of water in the nanostructure. So, the results show that in the presence of a nano-pore, the number of H 2 O molecules reaches to 496 and 568 in reservoirs 2 and 3. Also, the number of SiO 2 nanoparticles reaches 10 and 4 in reservoirs 2 and 3. This shows that in reservoirs 2 and 3, about 80% and 60% of the SiO 2 nanoparticles are separated. As mentioned before, the electric field prevents the passage of SiO 2 nanoparticles through the graphene nanosheet. As the number of graphene nano-pores increases by 2, 3, 4, and 5, the number of passing water molecules increases. Considering that the number of graphene nano-pores has increased and the movement path of particles has increased, the number of passing particles almost increases. However, the electric field prevents the passage of SiO 2 nanoparticles. According to the results, the suggested setup can be employed for designing highly efficient nanostructured membranes for air purification and monitoring. [Display omitted] [ABSTRACT FROM AUTHOR]

Improving bonding and mechanical strengths is important for the application of bond coats used in the construction of steel deck bridges. Graphene nanoplatelets (GNPs) are attractive nanofillers for polymer modification because of their low cost, ultra-high aspect ratio, and extraordinary thermal and mechanical performance. In this paper, GNPs were used to reinforce the epoxy asphalt bond coat (EABC). The morphology, viscosity–time behavior, contact angle, dynamic mechanical properties, and mechanical and bonding strengths of GNP-reinforced EABCs were investigated using laser confocal microscopy, a Brookfield rotational viscometer, a contact angle meter, dynamic mechanical analysis, a universal test machine, and single-lap shear and pull-off adhesion tests. GNP dispersed non-uniformly in the asphalt phase of EABC. The viscosity of the neat EABC was lowered with the inclusion of GNPs and thus the allowable construction time was extended. The existence of GNPs enhances the hydrophobicity of the neat EABC. When adding more than 0.2% GNP, the storage modulus, crosslinking density and glass transition temperatures of both asphalt and epoxy of the neat EABC increased. The mechanical and bonding properties of the neat EABC were greatly enhanced with the incorporation of GNPs. Furthermore, the mechanical and bonding strengths of the modified EABCs increased with the GNP content. GNP-reinforced EABCs can be utilized in the pavement of long-span steel bridges with long durability. [ABSTRACT FROM AUTHOR]

This paper presents a blueprint for major exploration advances in graphene-based nanolubricants and nanofluids achieved over the last few years. Graphene is being studied worldwide as a coolant and lubricant additive due to its excellent thermophysical and tribological properties. With this in mind, a variety of synthesis methods, characterization techniques, and methods are highlighted for studying tested and developed properties. In addition to that, factors influencing the thermal conductivity, viscosity, stability, and applications of different nanoparticles are described in detail. Improvement of viscosity, antiwear, and thermal conductivity behavior of graphene-based nanofluids plays a vital role, but not many mechanisms have been introduced. Graphene nanoparticles are most effective and promising the better heat transfer rate among other mostly used nanoparticles in the cooling and lubricant sector. It increases the effectiveness almost two times at higher concentration suspended in water. This complete overview, along with key comments and recommendations, may relate to future headings in this audit area. [ABSTRACT FROM AUTHOR]

In this paper, with the aim of improving hydrogen storage efficiency, cerium vanadate/reduced graphene oxide (CeVO4/rGO) nanocomposite was synthesized through a one-step hydrothermal method due to its unique characteristics, including suitable electrochemical behavior, high specific surface area, and high porosity. In addition to controlling the growth of CeVO4 nanoparticles, hydrazine reduces graphene oxide (GO) to reduced graphene oxide (rGO) and enables one-step synthesis. FESEM images showed that the rod-like CeVO4 nanoparticles were dispersed on the graphene plates. According to the obtained storage results, with the addition of graphene, the synergistic effect between the layers has increased and, as a result, the hydrogen storage capacity has increased. The highest amount of electrochemical storage of hydrogen in the synthesized nanocomposite was about 5430 mAh/g, which is a significant result compared to other nanostructures used. [ABSTRACT FROM AUTHOR]

Polymer composites are increasing in demand in energy storage applications including in the electronic as well as electrical industries due to the ease of processing of these materials with associated advantages like light weight, corrosion resistance, and high mechanical strength. In this investigation, efforts are made to enhance the charging and discharging properties of epoxy/carbon fabric composite by the addition of graphene nanoplatelets (GNPs) into the epoxy/carbon matrix. The performance of the composites with graphene platelets of 0.5 to 5 wt. % in epoxy were characterized and 1wt.% percolation threshold was observed poor performance in gravimetric charge and discharge characteristics were observed. Based on the percolation threshold Epoxy-Carbon fabric (EC) composites and Epoxy-Carbon fabric with 1 wt. % of GNP (ECG1) composites were fabricated using a vacuum-assisted resin transfer molding technique. The electrochemical performance was studied using the Cyclovoltammetry test and 0.1 M of Na2SO4 as a supporting electrolyte. The Galvanostatic Charge-Discharge characteristics were carried-out for EC and ECG1 at a scan rate of 80 sec, 300 sec, 4000 sec with 2 runs and 8 runs. The composite EC didn't not show GCD characteristics, but the symmetry of charge-discharge characteristics observed for ECG1 and same are discussed in this paper. These highly effective, and excellent characteristics demonstrate that Epoxy-GNP-CF composites may be promising composites for practical energy storage applications. [ABSTRACT FROM AUTHOR]

In this paper, a rotating functionally graded (FG) polymer nanocomposite shaft-disk assembly reinforced with graphene nanoplatelets (GPLs) resting on elastic supports is modelled and its vibration behaviours are analysed. The effective material properties of the shaft and disk are assumed to vary along their radius directions and determined via the Halpin–Tsai model together with the rule of mixture. Different non-uniform and uniform distributions of GPLs in the rotating assembly are taken into account. In accordance with the finite element (FE) method, the modelling and free vibration analysis of the nanocomposite shaft-disk rotor system is conducted. To verify the present analysis, both the theoretical and experimental methods are employed. A comprehensive parametric study on the effects of the graphene nanoplatelets (GPL) weight fraction, GPL distribution pattern, length-to-thickness ratio and length-to-width ratio of GPLs, shaft length, elastic support stiffness and rotating speed on the free vibration results are investigated, which gives effective ways to achieve improved mechanical performance of a rotating nanocomposite disk-shaft assembly. [ABSTRACT FROM AUTHOR]

The paper investigates nonlinear dynamic behavior of functionally grade graphene nanoplatelets reinforced (FG-GPLRC) shell with radius as a high-order function using the classical thin shell theory (CTST) and the Von Karman-Donnell geometrical nonlinearity assumption. Different from cylindrical or conical shells, variations of radius are formulated as quadratic or/and cubic functions, generating three types of funnel shells. To verify the computation, the fundamental frequencies are compared with the previous literatures and Finite Element Analysis. The effects of various parameters including geometries, materials, temperature are considered. Obtained results of the shell promisingly make a significant contribution to various fields of engineering. [ABSTRACT FROM AUTHOR]

This paper presents the characterisation and for the first time the application of a nanocomposite based on reduced graphene oxide (rGO) modified with antimony nanoparticles (SbNPs) in the stripping analysis of Cd2+, Pb2+, Cu2+ and Hg2+ in natural water samples. The nanocomposite was easily synthesised by a chemical reduction approach using sodium borohydride as the reductant agent. The designed experiment investigated the remarkable rGO electronic properties with the synergetic combination of metallic SbNPs. The results showed that the GC/rGO-SbNPs electrode selective detected the heavy metal ions (HMIs) with suitable sensitivity. Under optimal conditions, the proposed electrode showed a good linear relationship with the concentration of Cd2+, Pb2+, Cu2+ and Hg2+ ranging from 0.1 to 4.5 µmol L−1 with detection limits for simultaneous determination of 45.3, 16.5, 34.1 and 4.8 nmol L−1, respectively. This presented work enables a full understanding of rGO-SbNPs properties in stripping analysis of HMIs, as well as a novel approach for future in situ analysis. [ABSTRACT FROM AUTHOR]

Researchers are trying to tackle water scarcity in numerous ways. One of those ways is the use of nanotechnology in water processing and purification. The current work involves the fabrication and optimization of activated carbon and graphene‐based hybrid water purification system. Five different concentrations of methylene blue and deionized water (DI) dye solutions were used, and they were filtered in three different cycles. For the potential usage on the consumer side, a small‐scale, low‐cost water filter is developed using activated carbon, commercial filter paper, and graphene nanoplatelets. The filter paper is used to hold mixtures of the activated carbon and graphene nanoplatelets within the water filter. The conductivity, TDS, and pH are measured for the feed water and the processed water using an Oakton EcoTestr and Apera Instruments PH60 Premium Pocket pH meter, respectively. A UV‐Vis spectrometer is used to measure the absorption of solutions. The distribution and adsorption of the dye particles were observed by scanning electron microscopy. Practitioner points: These results show the effectiveness of the system in the removal of dye particles above a given particle size.The concentration of the dye solution decreased after every cycle.The GnPs filtration system more effectively dye particles as compared to the filtration system containing only Activated carbon.UV‐Vis spectroscopy results showed that the methylene blue dye particles decreased after every cycle.This research can open a broad area of projects toward waste/wastewater practice for particles above a certain particle size. [ABSTRACT FROM AUTHOR]

In this paper, porous Mn 3 O 4 –Fe 3 O 4 nanoparticles with highly uniform composition are in-situ anchored on reduced graphene oxide (rGO) nanosheets by a simple cyanometallic framework template method. Thanks to the synergistic effects between the porous Mn 3 O 4 –Fe 3 O 4 nanoparticles and the well-conductive rGO nanosheets, the Mn 3 O 4 –Fe 3 O 4 /rGO composites present superior electrochemical lithium storage performances with a great reversible capacity of 1013 mAh g−1 after 100 cycles at 0.1 A g−1, satisfactory rate capability of 510 mAh g−1 at 3.0 A g−1, and eminent long-term cycle stability of 804 mAh g−1 after 500 cycles at 0.5 A g−1. It is demonstrated that the rGO can not only act as a conducting matrix, but also buffer the volume expansion and avoid the aggregation of the Mn 3 O 4 –Fe 3 O 4 nanoparticles during charging-discharging. The work provides a simple strategy for designing and fabricating advanced multi-component metal oxide-based anodes for high-performance lithium-ion battery. • Mn 3 O 4 –Fe 3 O 4 /rGO is prepared by a simple cyanometallic framework precursor route. • Mn 3 O 4 –Fe 3 O 4 nanoparticles are well decorated on rGO sheets with adjustable loading. • The optimized Mn 3 O 4 –Fe 3 O 4 /rGO displays superior lithium storage performance. • The synergistic effect is responsible for the enhanced performance. [ABSTRACT FROM AUTHOR]

Rocket kerosene plays an important role in the regenerative cooling process of rocket thrust chambers. Its thermal conductivity determines the cooling efficiency and the tendency to coke in rocket kerosene engines. In this paper, graphene nanoplatelets (GNPs) were introduced into rocket kerosene to improve its thermal conductivity. Molecular dynamics simulation was used to investigate the thermal conductivity of the composite system and its underlying thermal conductivity mechanism. Firstly, by studying the effect of the mass fraction of GNPs, it was found that, when the graphene mass fraction increases from 1.14% to 6.49%, the thermal conductivity of the composite system increases from 4.26% to 17.83%, which can be explained by the percolation theory. Secondly, the influence of the size of GNPs on the thermal conductivity of the composite system was studied. Basically, the thermal conductivity was found to increase by increasing the aspect ratio of GNPs, indicating that GNPs with a higher aspect ratio are more conducive to improving the thermal conductivity of rocket kerosene. By carefully analyzing the effect of the size of GNPs on thermal conductivity, it was concluded that the thermal conduction enhancement by adding GNPs is determined by the combined effect of the percolation theory and the Brownian motion. The results of the temperature effect study showed that the ratio of thermal conductivity to rocket kerosene increased from 1.16 to 1.26 and from 1.07 to 1.11 for the composite systems, with graphene sizes of 41.18 Å × 64.00 Å and 24.14 Å × 17.22 Å in the temperature range of 293 K to 343 K, respectively. It is further proved that the Brownian motion of GNPs has a non-negligible effect on the thermal conductivity of the composite system. This work provides microscopic insights into the thermal conduction mechanism of GNPs in nanofluids and will offer practical guidance for improving the thermal conductivity of rocket kerosene. [ABSTRACT FROM AUTHOR]

Nitrogen doped carbon materials containing transition metal nanoparticles have attracted much attention as bifunctional oxygen electrocatalysts. In this paper, the template etching method is used to obtain the nitrogen‐doped graphene with abundant macropores embedded with cobalt nanoparticles (Co@N−C). The prepared Co@NC‐800 catalyst has a half‐wave potential (E1/2=0.835 V) close to Pt/C and good stability in excess of Pt/C for oxygen reduction reaction (ORR). At the same time, the catalyst has good oxygen evolution reaction (OER) performance. In addition, zinc‐air batteries (ZABs) based on the Co@NC‐800 catalyst show good cycle stability of up to 200000 s and high power density of 73.5 mW cm−2. The synergistic effect of the integrated component between nitrogen‐doped graphene and cobalt nanoparticles as well as the macroporous structure endow Co@NC‐800 with abundant exposed active sites and mass/electron transfer capacity, thus leading to the high electrocatalytic activity. This work shows potential for practical applications in electrochemistry. [ABSTRACT FROM AUTHOR]

Lightweight blades with high strength are urgently needed in practical rotor engineering. Sandwich structures with porous core and reinforced surfaces are commonly applied to achieve these mechanical performances. Moreover, blades with large aspect ratios are established by the elastic plate models in theory. This paper studies the vibration of a rotating sandwich pre-twist plate with a setting angle reinforced by graphene nanoplatelets (GPLs). Its core is made of foam metal, and GPLs are added into the surface layers. Supposing that nanofillers are perfectly connected with matrix material, the effective mechanical parameters of the surface layers are calculated by the mixing law and the Halpin–Tsai model, while those of the core layers are determined by the open-cell scheme. The governing equation of the rotating plate is derived by employing the Hamilton principle. By comparing with the finite element method obtained by ANSYS, the present model and vibration analysis are verified. The material and structural parameters of the blade, including graphene nanoplatelet (GPL) weight faction, GPL distribution pattern, porosity coefficient, porosity distribution pattern, length-to-thickness ratio, length-to-width ratio, setting angle and pre-twist angle of the plate are discussed in detail. The finds provide important inspiration in the designing of a rotating sandwich blade. [ABSTRACT FROM AUTHOR]

• GNPs can reduce the viscosity and weaken the structural strength of waxy oil. • Dosage and doping temperature are the primary factors influencing the GNPs' efficacy. • The cold flowability improvements might be attributed to GNPs' nano-templating effect. Waxy crude oil exhibits poor cold flowability and complex rheological behavior at ambient temperature, posing a series of flow assurance challenges for its production and transportation. In this paper, the effects of graphene nanoparticles (GNPs) at various dosages and doping temperatures on the cold flow behaviors, such as yield stress and moduli as well as apparent viscosity, of a waxy crude oil were systematically investigated. The results indicate that the cold flowability of the waxy crude oil could be improved with an increasing GNPs dosage from 0 to 200 ppm. However, the GNPs' efficacy cannot be further improved beyond the dosage of 200 and up to 500 ppm. Doping temperature is another primary factor influencing the GNPs' efficacy. The apparent viscosity gradually decreases with the doping temperature increase from the wax appearance temperature (WAT) to the wax dissolved temperature (WDT). However, further improvement of efficacy is not observed by the continued increase of doping temperature above the WDT. Microscopy, impedance, and X-ray diffraction results indicate that GNPs could accumulate on wax particle surfaces, acting as the nano-templating effect, and thus weaken the attraction among the wax particles, which may contribute to the cold flowability improvement of waxy crude oil. [ABSTRACT FROM AUTHOR]

Transition metals are promising catalysts for the hydrogen evolution reaction (HER), and their electrocatalytic performance can be enhanced by high entropy alloys (HEAs) formation and carbon coating. In this study, a series of HEAs nanoparticles coated with N-doped graphene layers of controllable thickness are prepared using a simple method. Among them, the CuNiFeCoCrTi@NC nanoparticles exhibits excellent HER activity and stability. [Display omitted] • A simple method for synthesizing HEA@NC NPs and controlling the thickness of N-doped graphene shell. • Excellent stability of HEA@NC NPs in alkaline solution. • The evolution of HER performance, spanning from ternary alloy to HEAs, was investigated. • The effect of N-doped graphene shell on the HER activity of HEAs was explored. Electrochemical water splitting is an environmentally friendly technology for producing hydrogen energy. Recent studies have shown that high entropy alloys (HEAs) and N-doped graphene layers coated alloys have superior hydrogen evolution reaction (HER) performance compared to traditional alloys. This paper presents a simple method for synthesizing N-doped graphene layers coated HEAs with controllable thickness. NiFeCo-based alloy materials are prepared using this method and used as HER catalysts in alkaline conditions. Experimental results and density functional theory (DFT) calculations demonstrate that the CuNiFeCoCrTi@N-doped graphene nanoparticles (CuNiFeCoCrTi@NC NPs) with a graphene shell of 2–3 layers exhibit the best hydrogen evolution performance. The improvement of hydrogen evolution performance should be related to the unique properties of HEAs and coating the surface of alloys with thin graphene shell. This study presents a simple and efficient method for synthesizing HEA@NC NPs, which can be used as an efficient electrocatalyst in alkaline water splitting systems. [ABSTRACT FROM AUTHOR]

Damping and mechanical properties are often incompatible in metallic materials. In this paper, bio-inspired laminated graphene nanoplatelets (GNPs) reinforced Al-30Zn alloy matrix composites with an outstanding combination of damping-mechanical properties are prepared using a flake powder metallurgy (FPM) process. The increased grain/phase boundary owing to grain refinement improves the intrinsic damping properties of the composites, while the lamellar grains promote the oriented alignment and crack deflection of GNPs. The multilayered GNPs with large specific surface area experienced repeated stretching and compression during cyclic bending deformation, leading to intense interfacial frictional slip, and GNPs' high intrinsic thermal conductivity also helped to dissipate heat quickly, which promoted mechanical energy dissipation. The improvement in mechanical properties is mainly attributed to grain refinement, the load transfer effect of GNPs and their interaction with dislocations. The Al-30Zn-0.5GNPs composites showed the best combination of damping properties and mechanical properties. • Two steps flake powder metallurgy was utilized for the preparation of Al-30Zn-GNPs composites. • Laminated structure of Al-30Zn alloys facilitates interfacial damping. • Incorporation of GNPs improves damping properties and mechanical properties. • Interfacial and dislocation damping are the main damping mechanisms in composites. [ABSTRACT FROM AUTHOR]

Although perovskite solar cells have shown outstanding photovoltaic performance, there are still various obstacles that limit their performance and that remain as significant challenges. Weak optical absorption rate in the infrared region is a significant drawback for this kind of solar cell. In this paper, Au@SiO2@Graphene nanoparticles (NPs) as nano-photonic inclusions in the perovskite layer are proposed and investigated theoretically. Unlike conventional nanoparticles, these NPs exhibit strong, multiple plasmon resonances at low energies. The effect of geometrical parameters, periodicity, and the location of the Au@SiO2@Graphene NPs in the perovskite layer upon the performance of the PSCs are investigated. Under improved conditions, an absorption enhancement of 32% is obtained compared to pristine devices. Also, the result attained from coupled optical-electrical simulation of the improved device demonstrated 20.05% power conversion efficiency. These improvements have been achieved due to the plasmonic near-field enhancement effects of Au@SiO2@Graphene nanoparticles along with increased light-scattering from these NPs. [ABSTRACT FROM AUTHOR]

Nanomaterials offer a wide range of applications in environmental nanotechnology. Hazardous pollutants in the environment are needed to be detected and controlled effectively to avoid human health risks. In this paper, we described the fine-controlled growth of In 2 O 3 nanoparticles embedded on GO nanosheets by a facile precipitation method. The In 2 O 3 @GO nanocomposites exhibited outstanding gas sensing performance as compared with pure In 2 O 3 nanoparticles towards NO 2. At 225 °C, the sensor displayed high selectivity, best response (78) to 40 ppm NO 2 , quick response, and recovery times of 106s/42s. The improved sensing performances of the nanocomposite were attributed to large surface area, high gas adsorption-desorption capability, and the formation of p-n heterojunctions between In 2 O 3 nanoparticles and GO nanosheets. The excellent gas detecting activities validate In 2 O 3 @GO nanocomposites as a promising candidate in the NO 2 gas sensor industry. [ABSTRACT FROM AUTHOR]