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Three-dimensional (3D) reduced graphene oxide (rGO)/Ti2CTx MXene hybrid aerogels were effectively prepared by a two-step method involving hydrothermal reaction and freeze-drying. The intimately coupled rGO/Ti2CTx hybrid aerogel combined high electrical conductivity, large interlayer spacing, and excellent mechanical stability of Ti2CTx, which not only effectively prevents the self-restacking of Ti2CTx nanosheets, exposes more active sites exposed, and improves the volume change during the charge/discharge process but also increases the accessibility of ions and promotes the rapid transfer of ions/electrons. As a result, rGO/Ti2CTx 17.5–2.5 as the working electrode of electric double layer capacitors delivers a large specific capacity (107.05 F g−1 at 0.5 A g−1 in a 1M Na2SO4 electrolyte), a high rate capability (maintains 30% of its initial capacitance at 10 A g−1, which is much better than rGO and Ti2CTx), and excellent long-term large-current cycle stability (the initial capacitance remains above 71.1% after 10 000 cycles at 1 A g−1). In addition to providing a high-performance electrode for supercapacitors, this study proposes an efficient and time-saving strategy for constructing 3D structures from 2D materials. [ABSTRACT FROM AUTHOR]

Ge2Sb2Se4Te1 (GSST) exhibits unprecedented broadband transparency over the infrared wavelength range and has emerged as a promising functional material in photonic applications that operate in the optical fiber telecommunication wavelength band. In this work, GSST and graphene oxide (GO) are integrated into an optical fiber link to achieve all-fiber non-volatile multilevel photonic memory. The GSST and GO (GSST-GO) duo-layer hybrid structure is sandwiched between two optical fiber ferrules, where the GO acts as a localized heat source to initiate the phase transition of GSST upon optical excitation. The GSST-GO-coated fiber exhibits a low insertion loss of 0.8 dB and a maximum readout contrast of about 32%, with at least five distinguished memory states. The response time of the device is measured in the range between 2.5 and 9.5 μs. This work serves as a proof of concept on implementing the GSST-GO duo-layer hybrid structure in optical fiber platform to realize all-fiber non-volatile multi-bit channel control or data storage. [ABSTRACT FROM AUTHOR]

Incorporating heteroatoms into graphene lattice results in enhanced electrical conductivity and electrochemically active sites and has significant importance in developing high-performance supercapacitors. In this study, sulfur and nitrogen co-doped graphene aerogel is synthesized via hydrothermal technique followed by a simple but effective freeze-thawing and ambient pressure drying process (referred to as SN-GA). The process requires low-cost raw materials and cost-effective equipment without the utilization of any special instrument that operates at ultra-low temperatures, under high pressure, or vacuum environment. Ammonium sulfate [(NH4)2SO4] and ethylenediamine are used as a source of sulfur and nitrogen and as a reducing agent. (NH4)2SO4 with different molarities (0, 12, 24, and 36 mM) are used to synthesize four different aerogel samples marked as GA, SN-GA1, SN-GA2, and SN-GA3. The electrode is prepared using an SN-GA2 sample, exhibiting an outstanding specific capacitance of 244 F g−1 at an applied current density of 1 A g−1 with almost 98.5% Coulomb efficiency. Furthermore, based on the SN-GA2 sample, the symmetrical supercapacitor is fabricated, displaying an energy density of 18.14 Wh kg−1 at a power density of 498.4 W kg−1. Hence, SN-GA2 renders a promising material for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Potential applications of previously synthesized pillared graphene oxide frameworks with phenyldiboronic acid linkers in the field of the adsorption and separation of polar protic and aprotic liquid solvents have been systematically explored using grand canonical Monte Carlo simulations. Particular attention was initially paid to the adsorption of pure liquid water, methanol, and dimethyl sulfoxide. The results obtained a significant increase in the isosteric heat of adsorption at low uptake in the case of dimethyl sulfoxide, which is about 17.9 and 26.8 kJ/mol higher than the values corresponding to methanol and water adsorption. These findings indicated that from a thermodynamic point of view, these pillared graphene oxide frameworks could be used in the separation of dimethyl sulfoxide–water liquid mixtures. Systematic grand canonical Monte Carlo simulations were then subsequently performed for dimethyl sulfoxide–water mixtures, with a low dimethyl sulfoxide concentration. The calculated values of the separation selectivity indicate that these materials could have potential applications in the separation of these mixed liquid solvents. Molecular dynamics simulations performed for a representative adsorbed mixture have revealed a substantial slowing down of the dynamics under confinement, particularly in the case of the hydrogen bonds formed between water and dimethyl sulfoxide. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is a two-dimensional, mechanically strong, and chemically tunable material for separations. Elucidating GO–ion–water interactions at the molecular scale is highly important for predictive understanding of separation systems. However, direct observations of the nanometer region by GO surfaces under operando conditions are not trivial. Therefore, thin films of GO at the air/water interface can be used as model systems. With this approach, we study the effects of alkali metal ions on water organization near graphene oxide films at the air/water interface using vibrational sum frequency generation (SFG) spectroscopy. We also use an arachidic acid Langmuir monolayer as a benchmark for a pure carboxylic acid surface. Theoretical modeling of the concentration-dependent sum frequency signal from graphene oxide and arachidic acid surfaces reveals that the adsorption of monovalent ions is mainly controlled by the carboxylic acid groups on graphene oxide. An in-depth analysis of sum frequency spectra reveals at least three distinct water populations with different hydrogen bonding strengths. The origin of each population can be identified from concentration dependent variations of their SFG signal. Interestingly, an interfacial water structure seemed mostly insensitive to the character of the alkali cation, in contrast to similar studies conducted at the silica/water interface. However, we observed an ion-specific effect with lithium, whose strong hydration prevented direct interactions with the graphene oxide film. [ABSTRACT FROM AUTHOR]

As water pollution is increasing due to industrialization, there is a high demand for easy-processing photocatalytic materials to clean wastewater. Here, the improvement in the photocatalytic dye degradation effect of graphene oxide (GO) surfaces, made of ultra-sonication assisted modified Hummer's method, is demonstrated with increasing alumina (Al2O3) concentration in the range of 4–30 wt. %. Scanning electron microscopy and x-ray diffraction results suggest a gradual increment in crystalline Al2O3 nanoparticles (NPs) by reducing GO, in good agreement with the first-principles calculations. Moreover, x-ray photoelectron spectroscopy reveals the appearance of oxygenated functional groups with increasing Al2O3 concentration, leading to the formation of defect-rich GO as demonstrated by Raman spectroscopy. Ultraviolet-visible spectroscopy further reflects a maximum reduction in the optical bandgap from 1.88 to 1.56 eV up to a concentration of 15 wt. % Al2O3. Interestingly, the methylene blue degradation efficiency of GO under ultraviolet irradiation is also found to be improved from 45% to 64% with 15 wt. % Al2O3, whereas the formation of Al2O3 NPs in the range of 100–300 nm with 30 wt. % Al2O3 is found to be detrimental for photocatalytic activity. [ABSTRACT FROM AUTHOR]

In this paper, we have investigated red light (∼ 660 nm) and magnetic field dependence of impedance across (100 − x)% ZnO(zinc oxide)– x % rGO(reduced graphene oxide)/La 0.7 Sr 0.3 MnO 3 (LSMO)/ITO (x =0,0.6,0.8,100) heterostructure devices. Field-induced scattering due to the spin filter effect and spin polarized tunneling (SPT) have been extracted from the zinc oxide–reduced graphene oxide nanocomposite/LSMO space charge region (ZnO–rGO/LSMO SCR) and the LSMO active region of the devices, respectively. Higher SPT leads to higher LSMO SCR scattering across the devices. Devices with higher rGO contents could not be fitted with two RC circuits as resistance values because the two phenomena are incomparable with each other. Light-induced scattering has been observed at the ZnO–rGO nanocomposite active region and ZnO–rGO/LSMO SCR of the devices. For composite devices with x =0.8 and 0.6, higher photocarrier generation at ZnO–rGO nanocomposite active layer leads to enhanced scattering at LSMO SCR with light illumination. Light-dependent scattering at both regions, however, follows almost same decreasing trend for bare devices with x =0, 100. The decreasing trend of light-dependent scattering for ZnO/LSMO/ITO and rGO/LSMO/ITO bare devices suddenly gets reversed and, eventually, follows an increasing trend at magnetic field ambiance of 0.5 and 1 kOe, respectively. The LSMO SCRs of the bare devices got enhanced with the field, leading to a light-dependent response similar to composite devices at the higher field. [ABSTRACT FROM AUTHOR]

This study investigated the improvement of the electro-optical properties of a liquid crystal (LC) cell fabricated through brush coating using graphene oxide (GO) doping. The physical deformation of the surface was analyzed using atomic force microscopy. The size of the groove increased as the GO dopant concentration increased, but the direction of the groove along the brush direction was maintained. X-ray photoelectron spectroscopy analysis confirmed that the number of C–C and O–Sn bonds increased as the GO concentration increased. Since the van der Waals force on the surface increases as the number of O–metal bonds increases, we were able to determine why the anchoring energy of the LC alignment layer increased. This was confirmed by residual DC voltage and anchoring energy measurements that were later performed. As the GO concentration increased, the width of the hysteresis curve decreased, indicating that the residual DC voltage decreased. Additionally, the 15% GO-doped sample exhibited a significant increase in its anchoring energy up to 1.34 × 10−3 J/m2, which is similar to that of rubbed polyimide. It also secured a high level of electro-optical properties and demonstrated potential as a next-generation thin-film display despite being produced via a simple brush-coating process. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) ultra-thin materials are more crucial than their bulk counterparts for the covalent functionalization of their surface owing to atomic thinness, large surface-to-volume ratio, and high reactivity of surface atoms having unoccupied orbitals. Since the surface of a 2D material is composed of atoms having unoccupied orbitals, covalent functionalization enables one to improve or precisely modify the properties of the ultra-thin materials. Chemical functionalization of 2D materials not only modifies their intrinsic properties but also makes them adapted for nanotechnology applications. Such engineered materials have been used in many different applications with their improved properties. In the present Perspective, we begin with a brief history of functionalization followed by the introduction of functionalized 2D materials. Our Perspective is composed of the following sections: the applications areas of 2D graphene and graphene oxide crystals, transition metal dichalcogenides, and in-plane anisotropic black phosphorus, all of which have been widely used in different nanotechnology applications. Finally, our Perspectives on the future directions of applications of functionalized 2D materials are given. The present Perspective sheds light on the current progress in nanotechnological applications of engineered 2D materials through surface functionalization. [ABSTRACT FROM AUTHOR]

The production of solar hydrogen presents a compelling opportunity to harness solar energy, playing a crucial role in addressing climate change and reducing reliance on fossil fuels. The progress of the hydrogen economy largely depends on establishing hydrogen production as a key foundational element. Moreover, selecting appropriate materials to support the main catalyst is vital for enhancing hydrogen production. This article furnishes a simple, affordable approach to existing water-splitting technologies that harness solar energy as the primary source for hydrogen production. To achieve this, the impact of GO content on ZnO nanoparticles/GO compositions' photoelectrochemical efficiency is studied. While all the presented samples show sensitivity to light, the sample with 0.35% GO performs the best, demonstrating the highest photocurrent density, the lowest rate of electron-hole recombination, and the greatest photoelectrochemical efficiency. • The PEC behavior of ZnO/GO nano composite was studied with varying GO amount. • Efficient separation of e & h decreases recombination and charge transfer resistance. • The 0.35-%G sample shows the most enhanced PEC and best photo stability properties. • The 0.35-%G sample has the narrowest band-gap and the lowest-intensity PL spectrum. • The 0.35%G sample provides the most optimal conditions for water splitting. [ABSTRACT FROM AUTHOR]

Compared with the composite coating with a single structure, the coating with a multilayer structure may possess better hydrogen barrier performance. Graphene oxide (GO) was chemically modified using polyethylene glycol diglycidyl ether (EGDE) to obtain modified graphene oxide (mGO). The introduction of epoxy groups in mGO would participate in the crosslinking reaction between the epoxy resin (EP) emulsion and the curing agent to improve the dispersion and adhesion of the middle layer in the sandwich structure. An EP/mGO/EP composite coating with a sandwich structure was prepared. The research found that the tightly stacked mGO middle layer in the sandwich structure played a crucial role. The average adhesion of the multilayer composite coating was about 9 MPa. The electrochemical impedance spectroscopy of layer 2-mGO composite coating showed that its modulus was up to 109 Ω cm2. The permeation current density ip and hydrogen content remained at low values of 1.38 μA and 1.34 ppm, respectively. The multilayer composite coating possessed not only excellent adhesion but also excellent corrosion resistance and hydrogen barrier performance. • Polyethylene glycol diglycidyl ether was used to covalently modify GO. • A "sandwich" structure composite coating of EP/mGO/EP was prepared. • The coating has excellent hydrogen resistance and corrosion resistance. [ABSTRACT FROM AUTHOR]

The energy gap between primary sources of energy like coal, oil, and natural gas will be 14 TW by 2050, hence finding sustainable sources of energy is the need of the day to bridge this gap. Hydrogen (H 2) in water is freely and abundantly available in nature, thus, the effective combination of light energy and water to produce hydrogen in an environmentally acceptable manner has a great potential to meet the current as well as future world's energy demand. Several semiconductors (SC's) have been employed to catalyze the formation of hydrogen from water (H 2 O). But the practical and feasible applicability of this system is limited due to photocatalyst high energy demand via wide band gap, quick recombination of photoexcited charge carriers (electron/hole pairs), easy nanoparticles agglomeration in solution and low photocatalyst surface area for adsorption. The incorporation of the majestic graphene material with the SC alone or in multiple SC's system can improve photocatalytic H 2 -production. Therefore, this review systematically presents an overview of, to shape graphene into a photocatalyst, graphene role in water splitting and in the interfacial charge-migration dynamics at surface contacts. We also focused on the built-in mechanism of the heterostructures comprises of photocatalyst (mainly TiO 2 , ZnO and WO 3) and graphene-based nanomaterials (pure graphene (G), graphene oxide (GO), reduced graphene oxide (r-GO)) and their combination thereof for H 2 generation in aqueous system. Composite comprised of SC's/graphene could potentially be a promising green light in the future of solar energy-led photocatalysis, specifically aimed at energy production. • This article provides a comprehensive overview on SC's/G composites for H 2 production. • The charge carrier's mechanism was thoroughly discussed in different SC's/G hybrids. • Ternary SC's/G heterostructure performed well for H 2 evaluation. • Future research directions for SC's/G heterostructures are outlined. [ABSTRACT FROM AUTHOR]

Highlights This paper reports on preparing two types of graphene oxide‐zinc oxide (GO‐ZnO) nano‐hybrids and their effect on the performance of polybutylene succinate (PBS) matrix. This view synthesized GO, ZnO, and GO‐ZnO nano‐hybrids at 1:1 and 1:2 weight ratios. Subsequently, various spectroscopy and microscopy analyses (FTIR, UV, Raman, AFM, and TEM) were employed to characterize the structure of synthesized nanomaterials. The obtained results revealed that the hybridization was successfully occurred and microstructure of two types of prepared nano‐hybrids are basically different depending on the preparation procedure. Following this, PBS nanocomposites with 0.5, 1, and 1.5 wt% of GO‐ZnO nano‐hybrids (NPs) were produced via the solvent‐blending method. The mechanical, microstructural, rheological, biodegradability and UV‐shielding properties of the fabricated films were then investigated. Mechanical properties showed that addition of 0.5 wt% ZnO‐GO nanohybrids improved elongation at break from 21.6% to 28.7% and increased tensile strength by 20%. However, rheological assessments showed a one‐order‐of‐magnitude decrease in viscosity with the addition of only 0.5 wt%. In degradation analysis, 100 percent of mass loss was observed during 5 weeks for PBS with 1.5 wt% of GO‐ZnO. PBS/GO‐ZnO nanocomposites indicated tailored mechanical properties, biodegradability, suggesting a promising potential in packaging applications. GO‐ZnO nanohybrids were successfully synthesized. Incorporating GO‐ZnO into PBS improved its hydrolytic degradation The thermal decomposition of PBS was accelerated by the addition of GO‐ZnO. Adding GO‐ZnO nanohybrids to PBS resulted in a drop in viscosity. Nanohybrids with higher ZnO content exhibited greater hydrolytic and thermal degradation. [ABSTRACT FROM AUTHOR]

One of the principal gaseous pollutants that endangers the environment and human health is nitrogen dioxide (NO2) gas, mainly emitted through combustion sources. Even at quantities of tens of ppb, prolonged exposure to NO2 can cause asthma symptoms or reduced respiratory function. Therefore, NO2 sensors with high sensitivity, accuracy, and low detection limits are highly desirable for protecting the environment and human health. Focusing on this issue, a low-cost and easy synthetic procedure was adopted for heteroatom (N, B)-doped reduced graphene oxide and a mesoporous MgFe2O4-based nanocomposite. Higher electrical conductivity of reduced graphene oxide and the defect generation due to heteroatom doping synergises with the sensing capabilities of mesoporous MgFe2O4. The designed sensor can sense up to a lower concentration of 10 ppm at room temperature. Along with the developed sensor's higher sensing capability, its good recyclability makes it favorable for detecting toxic gaseous analytes. The combined effect of higher surface area (N2 adsorption–desorption isotherm) and defect generation due to heteroatom doping and mesoporosity of MgFe2O4 spinel was the reason behind the higher response. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid nanocomposites (OIHN), with tailored surface chemistry, offer ultra-sensitive architecture capable of detecting ultra-low concentrations of target analytes with precision. In the present work, a novel nano-biosensor was fabricated, acquainting dynamic synergy of reduced graphene oxide (rGO) decorated hexagonal boron nitride nanosheets (hBNNS) for detection of carcinoembryonic antigen (CEA). Extensive spectroscopic and microscopic analyses confirmed the successful hydrothermal synthesis of cross-linked rGO-hBNNS nanocomposite. Uniform micro-electrodes of rGO-hBNNS onto pre-hydrolyzed ITO were obtained via electrophoretic deposition (EPD) technique at low DC potential (15 V). Optimization of antibody incubation time, pH of supporting electrolyte, and immunoelectrode preparation was thoroughly investigated to enhance nano-biosensing efficacy. rGO-modified hBNNS demonstrated 29% boost in electrochemical performance over bare hBNNS, signifying remarkable electro-catalytic activity of nano-biosensor. The presence of multifunctional groups on the interface facilitated stable crosslinking chemistry, increased immobilization density, and enabled site-specific anchoring of Anti-CEA, resulting in improved binding affinity. The nano-biosensor demonstrated a remarkably low limit of detection of 5.47 pg/mL (R2 = 0.99963), indicating exceptional sensitivity and accuracy in detecting CEA concentrations from 0 to 50 ng/mL. The clinical evaluation confirmed its exceptional shelf life, minimal cross-reactivity, and robust recovery rates in human serum samples, thereby unraveling the potential for early, highly sensitive, and reliable CEA detection. [ABSTRACT FROM AUTHOR]

This study is a pioneering study that experimentally and theoretically measures the effect of heterogeneous catalyst structure on hydrogen production. In this research, the catalytic activity of the (CQD/GO@Co) catalyst, which was formed by doping Co onto the synthesized graphene oxide (GO) on carbon quantum dots (CQD) obtained from caffeine by green synthesis, was investigated. The catalyst CQD/GO@Co was synthesized with high dispersibility and activity, and it was successfully employed in the hydrolysis of NaBH 4 for the first time. The effective catalytic compatibility of caffeine and cobalt element increased approximately 3 times on the GO layer. In order to determine the most effective catalyst conditions in the study, NaOH concentration, catalyst amount, NaBH 4 amount and temperature were tested under different reactant conditions. The catalyst was characterized using X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET) analyses. Field emission scanning electron micrographs (FESEM) were taken by Field emission scanning electron microscope (Zeiss, Sigma). Energy dispersive X-ray (EDX) spectra were obtained from Energy dispersive X-ray spectroscope. According to spherical aberration transmission electron microscopy studies, the uniform dispersion of Co nanoparticles (average diameter: ±3,1 nm) on CQDs, as well as the very small size and good dispersion of Cobalt (Co), are conducive to improved catalytic performance. This situation was determined by molecular modeling with the Non-scc GFN1xTB model and results supporting the experimental data were obtained. The maximum hydrogen production rate with sodium borohydride hydrolysis using cobalt-based catalyst increased approximately 32 times (from metallic crystal form of Co catalyst 2860 mL/min.(g.cat) to the present form 49,044 mL/min.(g.cat). The activation energy, activation enthalpy, and activation entropy of the Co@CQDs catalyst were founded to be 20.65 kJ mol−1, 2.64 kJ mol−1, and -108,97 J mol−1, respectively. • The study highlights the importance of the orientation of caffeine with the cobalt metal ion as a catalysis. • As the amount of sodium element with large van der Waals radius increases, positive blocks forms in solution. • Hydrolysis increases the interactions with high electrical dipole moments that occur with high vibration frequencies. [ABSTRACT FROM AUTHOR]

The use of ultrasound in the presence of semiconductor materials is considered a novel technique for the degradation of hazardous organic pollutants in water. In this study, graphitic carbon nitride (g), graphene oxide (GO), and Cobalt ferrite, CoFe 2 O 4 (CF) nanoparticles were synthesized via soft-template-assisted synthesis, Hummer's, and hydrothermal methods, respectively. Subsequently, the hybrid magnetic g-C 3 N 4 /CoFe 2 O 4 /GO (g-CF1@GO, g-CF2@GO, g-CF3@GO, and g-CF4@GO) nanocomposites were prepared via a simple hydrothermal route at 180 °C. The crystallite structure, functional groups, morphology, and energy band gaps were characterized by XRD diffraction, FT-IR, TEM, and UV–vis DRS. The heterostructure nanocomposites were formed, as evidenced by the TEM data, with an average crystallite size of 13.4 nm and band gap energies of 2.19–1.80 eV, suggesting their suitability for sono/photo degradation processes. Pyrene, a tetracyclic polycyclic aromatic hydrocarbon (PAH) was chosen as a model pollutant to evaluate the performance of the prepared nanocomposites toward sonocatalytic degradation. The nanocomposites exhibited higher degradation performances than individual materials. The sonocatalytic degradation of pyrene revealed that the g-CF4@GO nanocomposite exhibited the highest sonocatalytic activity and achieved 86.7 and 92.3 % degradation efficiency for 10 and 5 mg/L of pyrene under ultrasonic irradiation (40 mg/L, 50 W and 20 kHz) in 120 min. In addition, the sonocatalytic degradation of pyrene is performed in the absence of any oxidant and follows a pseudo-first-order kinetics. Trapping experiments were carried out to investigate the sonocatalytic degradation mechanism, and the results showed that ●O 2 − was the major reactive species. The easily recoverable magnetic nanocomposite via a simple magnet was tested for its recyclability and reusability, and it was observed that it could degrade up to 78 % of pyrene in four cycles. [ABSTRACT FROM AUTHOR]

One of the principal gaseous pollutants that endangers the environment and human health is nitrogen dioxide (NO2) gas, mainly emitted through combustion sources. Even at quantities of tens of ppb, prolonged exposure to NO2 can cause asthma symptoms or reduced respiratory function. Therefore, NO2 sensors with high sensitivity, accuracy, and low detection limits are highly desirable for protecting the environment and human health. Focusing on this issue, a low-cost and easy synthetic procedure was adopted for heteroatom (N, B)-doped reduced graphene oxide and a mesoporous MgFe2O4-based nanocomposite. Higher electrical conductivity of reduced graphene oxide and the defect generation due to heteroatom doping synergises with the sensing capabilities of mesoporous MgFe2O4. The designed sensor can sense up to a lower concentration of 10 ppm at room temperature. Along with the developed sensor's higher sensing capability, its good recyclability makes it favorable for detecting toxic gaseous analytes. The combined effect of higher surface area (N2 adsorption–desorption isotherm) and defect generation due to heteroatom doping and mesoporosity of MgFe2O4 spinel was the reason behind the higher response. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) and M13 bacteriophage can self-assemble to form ultra-low density porous structures, known as GraPhage13 aerogels (GPA). Due to the insulating nature of GPA and the challenges in producing highly conductive aerogels, it is paramount to explore ways to enhance the conductivity of GPA. Herein, we have developed a method to enhance the conductivity of GPA, via the integration and optimisation of 5 nm and 20 nm diameter gold nanoparticles (AuNPs) into the aerogel structure and systematically analysed the morphology, composition and spectroscopic properties of the resulting GPA-Au nanocomposite. The fabricated GPA-Au nanocomposites exhibited remarkable increases in conductivity, with the integration of 5 nm AuNPs leading to a 53-fold increase compared to GPA, achieving a performance of up to 360 nS/cm, which is within the range suitable for miniaturised semiconductor devices. The mechanism behind the conductivity enhancement was further investigated and attributed to GO-AuNP interactions increasing the carrier density by introducing new energy levels in the GO band gap or shifting its Fermi level towards the conduction band. These findings demonstrate the potential of functionalised AuNPs to significantly improve the electrical properties of GPA, paving the way for their application in gas sensors for biological and chemical detection and a new range of advanced semiconductor devices. [ABSTRACT FROM AUTHOR]

The escalating threat of bacterial infections to human health necessitates innovative antibacterial strategies and materials. Despite this need, there is still a significant demand for materials that combine high mechanical and thermal properties with biocompatibility. To address these urgent issues, our study investigates the development of poly(vinyl alcohol) (PVA) composite with graphene flakes (GF) as fillers. The aim is to strengthen the unique properties of graphene to enhance antibacterial activity. Graphene oxide (GO) was used as a surfactant to achieve stable graphene dispersion in water, preserving its inherent properties while avoiding the drawbacks associated with common surfactants, such as property reduction and complex removal processes. In this study, the mechanical and thermal properties of PVA composites containing GO and GF are superior to those of pristine PVA. Especially, the PVA‐2 composite exhibited a notable enhancement in both tensile strength and elongation at break compared with the PVA composite, with increases of 7.8% and 15% respectively. Moreover, PVA‐2, 4, and 6 composites exhibit significant antibacterial efficacy, achieving 4.8 and 4.9 log CFU/cm2 for Staphylococcus aureus and Escherichia coli, respectively. These results indicate that the enhanced oxidative stress induced by GO as a surfactant, combined with the physical damage caused by the increased GF nanostructures. This study highlights the potential of PVA/GF/GO composites in biomedical and tissue engineering applications, providing a promising pathway for the development of new antibacterial materials. [ABSTRACT FROM AUTHOR]

Fatigue in asphalt pavements is a major deterioration caused by repeated traffic loading. The objectives of this research were to investigate the fatigue performance of graphene oxide (GO) modified asphalt mixtures and evaluate the influence of temperature and stress level on the fatigue life of GO asphalt mixtures using response surface methodology (RSM). For this purpose, an indirect tensile fatigue test was conducted. The results showed that the application of GO increased the fatigue life of the asphalt mixture. The RSM analysis proposed a quadratic model with a high determination coefficient (R2 = 0.9977) to fit the experimental data. The ANOVA test showed that temperature, stress level, and GO percentage had a pronounced effect on the fatigue performance of the mixture. Furthermore, multi-objective optimization was used to achieve an optimized mixture proportion and verify the model's reliability by conducting validation experiments. The predicted and actual results were found to be in excellent agreement, with a variation of only 2.12%, suggesting that the model can accurately predict the fatigue life of the GO-modified asphalt mixture. [ABSTRACT FROM AUTHOR]

Composite electrospun nanofibers based on silk fibroin (SF), aminated reduced graphene oxide (NH2rGO), and oxidized-cellulose nanocrystals (AD-CNCs) were designed to promote the healing process by electrical conductivity. In this respect, CNCs were produced from cotton cellulose and oxidized in the presence of sodium periodate, and reduced GO was synthesized and functionalized with amine with p-anthranilic acid via an esterification reaction. Then the crosslink was prepared by the Schiff-base reaction between oxidized CNCs and NH2rGO. Electrospun nanofibers were prepared from silk fibroin, previously prepared from Bombyx Mori cocoons, AD-CNCs, and different ratios of NH2rGO. The SF/AD-CNCs/NH2rGO nanofibrous scaffold presented multiple propitious characteristics for cell proliferation and wound dressing including low cytotoxicity, a hydrophilic surface, thermal stability, and degradability. The physicochemical evaluations showed that with increasing the NH2rGO content, hydrophilicity and electroconductivity of nanofibers increased. The SF/AD-CNCs/NH2rGO biodegradable conductive scaffold with 2.5% NH2rGO content showed favorable nanofibrous structure, supporting and stimulating fibroblast cell proliferation and attachment. The SF/AD-CNCs/NH2rGO nanofibrous scaffold demonstrates the application potential in wound healing management. [ABSTRACT FROM AUTHOR]

Introduction: One effective method to combat bacterial infections is by using bacteria itself as a weapon. Lactobacillus is a type of fermenting bacterium that has probiotic properties and has demonstrated antimicrobial benefits against other bacteria. Cyclodipeptides (CDPs), present in the supernatant of Lactobacillus, possess several antimicrobial properties. Methods: In this study, the CDP fraction was isolated from the supernatant of Lactobacillus plantarum (L. plantarum). This fraction was then loaded onto graphene oxide nanosheets (GO NSs). The study assessed the substance’s ability to inhibit bacterial growth by using the minimum inhibitory concentration (MIC) method on A. baumannii and S. aureus strains that were obtained from clinical samples. To determine the substance’s impact on biofilm formation, the microtiter plate method was used. Moreover, the checkerboard technique was employed to explore the potential synergistic effects of these two substances. Results and discussion: According to the study, the minimum inhibitory concentration (MIC) of the desired compound was found to be 1.25  mg/ mL against S. aureus and 2.5  mg/mL against A. baumannii. Furthermore, at a concentration of 10  mg/mL, the compound prevented 81.6% (p  <  0.01) of biofilm production in A. baumannii, while at a concentration of 1.25  mg/mL, it prevented 47.5% (p  <  0.05) of biofilm production in S. aureus. The study also explored the synergistic properties of two compounds using the checkerboard method. Conclusion: In general, we found that GO NSs possess antimicrobial properties and enhance cyclodipeptides’ activity against S. aureus and A. baumannii. [ABSTRACT FROM AUTHOR]

This work presents a straightforward yet impactful method to enhance optical fibre sensor signals by integrating silver nanostars (AgNS) with graphene oxide (GO-AgNS) as a sensing material. AgNS were synthesized successfully via a one-step chemical reduction method using hydroxylamine as a reducing agent. The concentration of hydroxylamine was varied (7.2, 3.6, 1.8, and 0.9) x 10-4 %v/v to optimize AgNS formation, with the longest spike of the nanostar observed at lower hydroxylamine concentrations, as confirmed by transmission electron microscopy (TEM). UV-visible measurements revealed the highest peak absorption for AgNS synthesized using 0.9 x 10-4 %v/v hydroxylamine, 0.05 M sodium hydroxide, 0.8 mM silver nitrate, and 0.045 M sodium citrate, with an average length of 352.62 ± 59.72 nm measured from TEM images. GO was synthesized via a modified Hummer's method and mixed with AgNS at varying ratios (1:5, 1:10, 1:15, and 1:20) to form GO-AgNS coatings for the fibre optic probe. The GO-AgNS coating at a ratio of 1:5 exhibited the highest light absorption intensity, enhancing optical signal by 218% compared to GO-coated and 174% compared to AgNS-coated fibre optic sensors. These findings demonstrate that embedding AgNS onto the GO matrix structure as a sensing material significantly improves sensor performance, suggesting promising applications for super-sensitive, costeffective, and rapid detection in fibre optic-based sensors. [ABSTRACT FROM AUTHOR]

This paper introduces a novel wearable flexible gas sensor designed specifically for the detection of d‐limonene. The sensor utilizes materials recognized for their high efficiency‐to‐cost ratio, notably polyaniline (PANI) combined with carboxylated multiwalled carbon nanotubes (MWCNT) and graphene oxide (GO) as sensing layers. The study conducts a comprehensive analysis of the nanocomposite layers, examining their functional groups, morphology, topography, thickness, crystallinity, thermal behavior, surface area, as well as the size and volume of their pores. This examination showed distinctions among the nanocomposite layers. PANI/GO exhibited larger pore size and thickness, while PANI/MWCNT_COOH demonstrated a higher surface area. The analysis of thermal stability demonstrated that the film employing the DBSA dopant exhibited the lowest stability. Morphological characterizations showed a globular structure for PANI, tubular characteristics for PANI/MWCNT_COOH, and a flat nature for PANI/GO. When detecting d‐limonene, nanocomposite films doped with HCl demonstrated notably superior response levels. The gas sensors exhibited high sensitivity (>2.24 mV/ppm), a narrow range for the limit of detection (0.12–0.52 ppm), and excellent reversibility, stability, and selectivity. These findings suggest the possibility of broadening the application of gas sensors to monitor additional volatile compounds, with a particular emphasis on the online monitoring of agricultural products. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO), beyond its specialized industrial applications, is rapidly gaining prominence as a nanomaterial for modern agriculture. However, its specific effects on seed priming for salinity tolerance and yield formation in crops remain elusive. Under both pot-grown and field-grown conditions, this study combined physiological indices with transcriptomics and metabolomics to investigate how GO affects seed germination, seedling salinity tolerance, and peanut pod yield. Peanut seeds were firstly treated with 400 mg L⁻¹ GO (termed GO priming). At seed germination stage, GO-primed seeds exhibited higher germination rate and percentage of seeds with radicals breaking through the testa. Meanwhile, omics analyses revealed significant enrichment in pathways associated with carbon and nitrogen metabolisms in GO-primed seeds. At seedling stage, GO priming contributed to strengthening plant growth, enhancing photosynthesis, maintaining the integrity of plasma membrane, and promoting the nutrient accumulation in peanut seedlings under 200 mM NaCl stress. Moreover, GO priming increased the activities of antioxidant enzymes, along with reduced the accumulation of reactive oxygen species (ROS) in response to salinity stress. Furthermore, the differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) of peanut seedlings under GO priming were mainly related to photosynthesis, phytohormones, antioxidant system, and carbon and nitrogen metabolisms in response to soil salinity. At maturity, GO priming showed an average increase in peanut pod yield by 12.91% compared with non-primed control. Collectively, our findings demonstrated that GO plays distinguish roles in enhancing seed germination, mitigating salinity stress, and boosting pod yield in peanut plants via modulating multiple physiological processes. [ABSTRACT FROM AUTHOR]

Particle transfer method photoelectrodes show superior photoelectrochemical performance compared to traditional powder‐based methods, making them a promising solution for solar water splitting in sustainable energy. This study introduces an innovative nonvacuum particle transfer method for fabricating photoelectrodes on a conductive carbon substrate, addressing the challenges associated with the high costs and vacuum deposition processes of traditional methods. Utilizing a p‐type CuFeO2 powder semiconductor, a unique substrate is developed by applying a graphene oxide layer mixed with a small amount of silica binder on the particle layer's backside through ultrasonic atomization spraying. This layer is converted into multilayered reduced graphene oxide (ML‐rGO) via wet chemical reduction, resulting in a substrate boasting a high work function (4.8 eV), alongside remarkable chemical stability, mechanical strength, and conductivity. The fabricated CuFeO2 photocathode demonstrated an onset potential of 0.97 V versus RHE and a photocurrent density of 1.5 mA cm−2 at 0.6 V versus RHE for H2O2 reduction. Further enhancement is achieved by depositing Pt as a cocatalyst, which ensured stability for over 20 h in an alkaline medium for water splitting. This study sets a new benchmark for developing CuFeO2‐based photocathodes, paving the way for broader particle transfer method applications. [ABSTRACT FROM AUTHOR]

The nanoconfinement effect plays an important role in chemical reactions. Inspired by enzymes, this work presents a new way to conduct the rapid flow synthesis of benzothiazoles in the two-dimensional (2D) nanoconfined space created by a graphene oxide membrane. The conversion reaches 96.7% in a short reaction time of less than 23 s at 22 °C. [ABSTRACT FROM AUTHOR]

Polypyrrole (PPy) is favoured in energy storage for its high pseudo-capacitive performance, notably as polypyrrole nanotubes (PPyNTs) due to their easy synthesis, cost-effectiveness and electrochemical solid properties. Metal-organic frameworks (MOFs) have also gained attention for enhancing supercapacitors (SCs). In this study, we fabricated aerogel composites with PPyNTs, MOFs and reduced graphene oxide (rGO) as SC electrode materials. Varying concentrations of PPyNTs and rGO were explored, with MOFs added to assess their impact. Electrochemical tests revealed that the composite with PPyNTs and Zn-MOF achieved the highest specific capacitance of approximately 270 F/g at 0.5 A/g. [ABSTRACT FROM AUTHOR]

Although graphene oxide (GO) has extensive recognized application prospects in slow-release fertilizer, plant pest control, and plant growth regulation, the incorporation of GO into nano herbicides is still in its early stages of development. This study selected a pair of sweet corn sister lines, nicosulfuron (NIF)-resistant HK301 and NIF-sensitive HK320, and sprayed them both with 80 mg kg–1 of GO-NIF, with clean water as a control, to study the effect of GO-NIF on sweet corn seedling growth, photosynthesis, chlorophyll fluorescence, and antioxidant system enzyme activity. Compared to spraying water and GO alone, spraying GO-NIF was able to effectively reduce the toxic effect of NIF on sweet corn seedlings. Compared with NIF treatment, 10 days after of spraying GO-NIF, the net photosynthetic rate (A), stomatal conductance (Gs), transpiration rate (E), photosystem II photochemical maximum quantum yield (Fv/Fm), photochemical quenching coefficient (qP), and photosynthetic electron transfer rate (ETR) of GO-NIF treatment were significantly increased by 328.31%, 132.44%, 574.39%, 73.53%, 152.41%, and 140.72%, respectively, compared to HK320. Compared to the imbalance of redox reactions continuously induced by NIF in HK320, GO-NIF effectively alleviated the observed oxidative pressure. Furthermore, compared to NIF treatment alone, GO-NIF treatment effectively increased the activities of superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in both lines, indicating GO induced resistance to the damage caused by NIF to sweet corn seedlings. This study will provides an empirical basis for understanding the detoxification promoting effect of GO in NIF and analyzing the mechanism of GO induced allogeneic detoxification in cells. [ABSTRACT FROM AUTHOR]

This study fabricates multiscale glass fiber/epoxy composites by incorporating graphene nanoparticles (GNPs) and zinc oxide nanoparticles (ZnO NPs) to investigate the influences of NPs on the mechanical properties of composites. The composites are manufactured using the compression molding technique with different GNP contents (i.e., 0, 0.5, 1, and 1.5 wt.%), whereas the contents of glass fibers and ZnO NPs remained the same at 40 and 4 wt.%, respectively. Their mechanical properties, chemical compositions, and fracture morphologies are then evaluated. It is found that the mechanical properties of composites improve significantly at a lower content (i.e., 0.5 wt.%) of GNPs and tend to decrease at higher contents (i.e., 1 and 1.5 wt.%). The composite is composed of 0.5 wt.% GNPs exhibit maximum tensile modulus and strength of 6.74 GPa and 230.25 MPa, and flexural modulus and strength of 16.43 GPa and 831.79 MPa, respectively, impact strength of 47.25 kJ m−2, and maximum hardness (97.96 Shore D), among all nanocomposites. Moreover, fracture morphologies reveal that composite failure is predominately caused by fiber breakage, fiber‐matrix debonding, voids, and GNP agglomeration. The outcomes of this study provide some insights to promote the application of manufactured multiscale composites in the aerospace, automotive, and marine industries. [ABSTRACT FROM AUTHOR]

Heteroatom doping and good porous structure play a decisive role in the energy storage characteristic of graphene-based supercapacitors. In this study, nanocellulose/N, S co-doped graphene composite hydrogel (NC-NSGHs) electrode materials were successfully prepared by a one-step hydrothermal method. During the reaction, ammonium sulfate was used as heteroatom source and reducing agent, nanocellulose (NC) was used as spacer and electrolyte storage container, and high a concentration of graphene oxide (GO, 4 mg mL−1) was used to increase the bulk density of the material. The target product NC-NSGHs have ideal pore structure, good hydrophilicity, and rich heteroatom functional groups. The aqueous symmetrical supercapacitors (SCs) assembled by NC-NSGH-50 exhibits high gravimetric specific capacitance (0.3 A g−1, 280.6 F g−1), volumetric specific capacitance (0.3 A g−1, 406.9 F cm−3), excellent rate performance (20 A g−1, 81.06%) and superior cyclic performance. In addition, we added GO and NC into the PVA-KOH electrolyte system and developed a new gel electrolyte PVA-GN-KOH (PGNK). The flexible solid-state supercapacitors (FSSCs) fabricated by PGNK and NC-NSGHs display a high specific capacitance of 189.9 F g−1 (0.5 A g−1). Even at 20 A g−1, the rate performance of the device can reach 60.24%. The emergence of NC-NSGHs and PGNK provides new ideas for high-performance portable supercapacitors. [Display omitted] • Heteroatom doped graphene composites hydrogels are easily prepared. • The compact porous structure gives the composites high bulk density. • A new type of PVA-based electrolyte is prepared. • Excellent electrochemical characteristics are achieved. [ABSTRACT FROM AUTHOR]

In the current study, multi-layer graphene (MLG) and reduced graphene oxide (rGO) were effectively synthesized and characterized by several techniques, including FT-IR, XRD, TGA, CHNS/O Analyzer, Raman spectroscopy, UV–Vis spectroscopy, TEM, and SEM. The electrochemical hydrogen storage (EHS) capacity was measured through cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS). High-quality graphene (I D /I G < 0.16), obtained from the simple liquid phase exfoliation method, exhibited a remarkable hydrogen storage capacity, reaching up to 200 F g−1 which equals 0.1 wt%. Furthermore, MLG outperforms rGO in terms of coulombic efficiency, achieving 100% in 10 cycles as opposed to rGO's 50% under identical conditions. This study presents the first-ever EHS using a new method that shows promising results. [Display omitted] • The prominent parameters in electrochemical hydrogen storage were examined. • MLG (200 F g−1) outperformed rGO (25 F g−1) electrochemically. • MLG exhibited a discharge capacity 53 times higher than commercial one. • MLG reached 200 F g−1 without metal loading. • The LPE method was determined to have considerable potential in EHS. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO) was prepared from waste plastic using the two steps pyrolysis method and subsequently functionalized with ethylene diamine (EDA) to develop amino‐functionalized rGO (EDA‐rGO). To make the thermal and mechanical properties more proficient, EDA‐rGO was further incorporated as a nanofiller into a low‐density polyethylene (LDPE) matrix using the melt mixing method followed by hot‐pressing. A variety of analytical methods, such as FT‐IR, XRD, XPS, DSC, TGA, DMA, Raman spectroscopy, and HRTEM, were used to characterize the elements and morphology of rGO and EDA‐rGO. The results showed that the addition of 5 wt% EDA‐rGO to LDPE polymers significantly improved the mechanical and thermal properties, such as storage modulus by 62%, loss modulus by 67%, young's modulus by 123%, tensile strength by 79.83%, respectively. The thermal decomposition temperatures of 5%, 10% and 50% were increased by 14.01, 9.34, and 4.8°C, respectively. This study provides a feasible and ecologically sustainable way of repurposing plastic waste concurrently enhancing the properties of polymer composites. Highlights: Synthesis & functionalization of rGO from waste plastic using EDA.EDA‐rGO used as a nanofiller to fabricate LDPE polymer nanocomposites.EDA‐rGO enhanced the thermal stability of LDPE nanocomposites.The tensile strength & modulus of the LDPE composites are greatly improved.The storage, loss modulus, Tm and Tc enhanced by 62%, 67%, 4.4°C & 2.6°C. [ABSTRACT FROM AUTHOR]

In this paper, a molecular dynamics model and a finite element model of graphene oxide-reinforced composites were developed, and the effects of mass fraction of graphene oxide (GO) on the mechanical properties of GO/PA66 composites were analyzed. The molecular dynamics model was randomly distributed in the finite element model to achieve cross-scale calculations from nanometer to micron. The effect of the molecular dynamics model size on the tensile mechanical properties of the composites was evaluated, and it was found that the elastic modulus initially increased and then decreased with the increase in model size. The study revealed that GO is surrounded by numerous hydrogen bonds, and these enhance the mechanical performance of the composites. Subsequently, a finite element model of the GO-reinforced composites was developed. The mechanical properties obtained from the size-optimized model of the molecular dynamics simulation were randomly specified within the finite element model to create a fine-scale model. And the calculations showed that GO enhances the mechanical properties of the composite by altering the stress transfer paths in the composite and taking up a larger amount of stress. [ABSTRACT FROM AUTHOR]

Highlights This study used molecular dynamics simulations to investigate the effects of the distribution angle of graphene oxide (GO) on the mechanical properties and non‐reciprocity of composite materials. The results of uniaxial tensile tests indicated that the mechanical properties of the composites are optimal when the distribution angles of GO are at 30° and 45°. The 30° model has an elastic modulus of 5.79 MPa, which is higher compared to the other models. The 80° model, however, has much lower mechanical properties, with a modulus of 1.42 MPa lower than the 30° model. Similarly, the 50° model also exhibits poorer mechanical properties with an elastic modulus of 4.42 MPa. Additionally, the 50° model is 24% lower than the 45° model. Through simulations of shearing in different directions and with different strain rates, it was found that the sensitivity of different GO distribution angles to strain rates varies. When the distribution angle is at 45°, the mechanical non‐reciprocity of the composite material is more pronounced. Explored the mechanical properties of GO/PA66 composites at the molecular level. Revealed the microscopic mechanism of interaction between GO and PA66. The effect of GO distribution angle on uniaxial tensile properties was studied. Studied the mechanism of the effect of GO distribution angle on non‐reciprocity. [ABSTRACT FROM AUTHOR]

Highlights By incorporating nanomaterials into polymer matrices, nanocomposites can be produced with enhanced properties, combining the ease of processing thermoplastics with the superior physical characteristics of nanoparticles. In this study, fully bio‐based polyamide 1010 was used as the polymer matrix, with graphene oxide (GO), hexagonal‐boron nitride (h‐BN), and molybdenum disulfide (MoS2), both individually and in hybrids, serving as fillers. The tensile behavior of these nanocomposites was evaluated at room temperature and −40 °C, along with their morphology and microstructure. Results showed that the nanomaterials slightly shifted the polymer's crystallization temperature upward, indicating a small nucleating effect, but also hindered the development of crystalline domains, reducing the crystallization kinetics. Despite no change in the final crystalline form, nanocomposites with h‐BN and MoS2 showed lower microstructural order as evidenced by XRD. Regarding tensile behavior, GO provided the greatest toughening at room temperature due to its larger lateral dimensions and good chemical affinity with the matrix. However, at low temperatures, h‐BN‐based nanocomposites maintained the toughening effect better than GO‐based ones. This can be attributed to the lower order of the polymer's semi‐crystalline structure promoted by h‐BN, allowing greater energy dissipation. Surprisingly, hybrid fillers did not exhibit synergistic effects, with one nanomaterial hampering the effect of the other. However, SEM analysis indicated that the fracture mechanisms of the nanocomposites remained unchanged from the neat polymer, which makes them interesting options for applications that require desirable mechanical properties at a wide temperature range. GO showed the best toughening of polyamide 1010 at room temperature. Toughening at room temperature is mainly due to nanomaterials physical traits. Most nanofillers lowered polyamide's overall microstructural order. Toughening at −40 °C is mainly due to lower microstructural order. [ABSTRACT FROM AUTHOR]

We present an innovative process for directly transforming poly(ethylene terephthalate) (PET), a polymer extensively used in food and beverage packaging, into trans‐isomer‐enriched 1,4‐cyclohexanedimethanol (CHDM), a key ingredient in advanced specialty polymers. Our approach leverages a dual‐catalyst system featuring palladium on reduced graphene oxide (Pd/r‐GO) and oxalate‐gel‐derived copper‐zinc oxide (og‐CuZn), utilizing hydrogenation/hydrogenolysis relay catalysis. This method efficiently transforms PET into polyethylene‐1,4‐cyclohexanedicarboxylate (PECHD), which is then converted into CHDM with an impressive overall yield of 95 % in a two‐stage process. Our process effectively handles various post‐consumer PET plastics, converting them into CHDM with yields between 78 % and 89 % across different substrates. Additionally, we demonstrate the applicability and scalability of this approach through a temperature‐programmed three‐stage relay process on a 10‐gram scale, which results in purified CHDM with an isolated yield of 87 % and a notably higher trans/cis ratio of up to 4.09/1, far exceeding that of commercially available CHDM. This research not only provides a viable route for repurposing PET waste but also enhances the control of selectivity patterns in multistage relay catalysis. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is broadly investigated in the electrochemical field. However, for industrial applications, it still suffer from high pollution, low efficiency, poor production quality, and safety concerns associated with traditional synthesis methods. Herein, guided by theoretical analyses, a new oxygen‐atom‐transfer (OAT) mechanism for periodate oxidizing graphite is revealed, exhibiting controllable reaction activity, strong orbital interaction, and abundant electron transfer. Moreover, a flow chemistry strategy with high mass/heat transfer rates is designed to enhance interlayer diffusion and reaction dynamics between oxidants and graphite, ensuring the efficient synthesis of GO within several minutes. As a result, both low oxygen‐content GO with large size, and high oxygen‐content GO with adequate active sites can be precisely and safely synthesized. Benefitting from the controllability of oxygen content and lateral size, the as‐prepared GO sheets can be facilely assembled into fiber/film electrodes that present high mechanical flexibility, large electrical conductivity, and outstanding electrochemical performance. [ABSTRACT FROM AUTHOR]

Conjunction of 'n' and 'p'-type materials have gained considerable attention for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) as potential substitutions to noble metal based nanomaterials. Current work has been designed to synthesize mixed-phase nanocomposite (NC) based on copper (CuO) and zinc oxide (ZnO) nanowires (NWs) and reduced graphene oxide (rGO). A facile chemical reduction method was used for the preparation of NWs, rGO were prepared using modified Hummer's method and lastly CuO/ZnO NWs were grafted on rGO to fabricate NC (CuO/ZnO@rGO) by wet-chemical approach. Characterization techniques were employed to confirm the formation as well as different morphological features of NC. Noticeable D and G bands in Raman spectrum confirmed the formation of NC and EDAX confirmed the presence of C, O, Zn and Cu. XRD analysis has confirmed hexagonal wurtzite structure of NC with a crystallite size of 10.1392 nm. Synthesized material was then investigated for OER and HER in an alkaline medium. As electrocatalyst, NC exhibited overpotential (OP) of 1.678 V to accomplish 10 mA/cm−2 current density (J) in OER and −358 mV (10 mA/cm−2) for HER respectively. Tafel curves of CuO/ZnO@rGO in OER (42 mV dec−1) and HER (270 mV dec−1) were found similar enough to others studies. Proliferated electrochemical activities are responsible for such a lower OP and Tafel slope values that may be due to electronic couplings of copper and zinc, or the homogenous distribution of both the metal oxides which gives polydispersity in their structure as confirmed by SEM images. Promising results of the current study indicated high-performance of synthesized electrocatalyst. Further studies can be designed to evaluate the efficiency of different combinations of noble/non-noble metals or metal oxides with rGO as potential candidate for electrochemical reactions. [ABSTRACT FROM AUTHOR]

Over the last decade, there has been vital increase in utilization the renewable energy sources, leading to a heightened need for the production of a highly effective energy storage system. Enhancing the characteristics of the electrode material has the potential to address such issues. The perovskite composite comprising corban-based materials has many applications, primarily in energy storage system. In this manuscript, hydrothermal method was performed to synthesized a nanocomposite material consisting of perovskite like BaSnO 3 & reduced graphene oxide (rGO) for purpose energy storage application. This work used physical and electrochemical techniques to examine the properties of the synthesized BaSnO 3 /rGO nanocomposite material. The presence of rGO in BaSnO 3 /rGO nanocomposite resulted in an enhanced surface area because of its heightened redox activity. The BaSnO 3 /rGO nanocomposite sample demonstrated an electrochemical characterization through capacitance (C s) value of 1264 F g−1 @ 1 A g−1 with power 255W kg−1 and energy density of 45 Wh kg−1. Moreover, the material exhibited the highest level of cyclic stability after undergoing 5000th cycles and also stable for 50 h. Furthermore, the enhanced electrochemical characteristics of the synthesized BaSnO 3 /rGO nanocomposite may be ascribed to larger surface area, reduced resistances and accelerated flow of electrolytic ions in comparison to the separate components. However, the BaSnO 3 /rGO nanocomposite has promising potential as fabricated electrode sample for various electrochemical applications and future storage device electrodes. [Display omitted] • The BaSnO 3 /rGO nanocomposite electrode was synthesized for supercapacitor electrode. • The martial showed specific capacitance of 1264 F g−1 at current density of 1 A g−1. • The material demonstrated energy density for 45 Wh kg−1 and power density for 255 W kg−1 • The nanocomposite exhibited solution resistance 3.21 Ω. • The BaSnO 3 /rGO nanocomposite displayed enhanced capacitive behaviour. [ABSTRACT FROM AUTHOR]

In this research, graphene oxide (GO) as an adsorbent was used to remove norfloxacin and ceftriaxone antibiotics from aqueous solutions. All environmental factors affecting removal (e.g., pH, adsorbent mass, contact time, and concentration) were optimized in a discontinuous system. The design of experiments and the optimization of variables were carried out using the response surface method (RSM). The results of the analysis of variance (ANOVA) and the regression coefficients of the quadratic terms indicated that the responses were significantly affected by all the studied variables (P < 0.05). Also, the quadratic polynomial model results corresponded to empirical data with a high coefficient of determination (i.e., R² > 0.99 for both antibiotics). Besides, the adjusted R² (R²-adj >0.98 for both antibiotics) was close to R² values, indicating a good and acceptable statistical model. According to the results, the optimal removal of antibiotics by GO occurs in conditions of pH of 8, 0.034 g of the adsorbent mass, a sonication time of 20 min, and a concentration of 25 mg L-1. In these conditions, the maximum removal efficiencies of ceftriaxone and norfloxacin were equal to 95.87% and 98.64%, respectively. GO was recovered in five adsorption/desorption processes, and the removal efficiency declined very slightly after using the adsorbent for five cycles. Therefore, it is concluded that GO is an efficient and acceptable adsorbent for removing ceftriaxone and norfloxacin from aqueous environments. [ABSTRACT FROM AUTHOR]

The electrochemical reduction of CO2 (ERCO2) to valuable chemicals such as acetic acid/acetate offers a promising route to revolutionize chemical production and enhance sustainability. Here, we report the hydrothermal preparation of an electrocatalyst consisting of copper/titanium dioxide/reduced graphene oxide (Cu‐TiO2/rGO) for ERCO2 in aqueous medium. The metal‐support (TiO2/rGO) was pre‐synthesized by combining an aqueous solution of TiO2 and GO in an autoclave at 150 °C for 20 h. Then TiO2/rGO was added to synthesized Cu colloid formed through the reduction of copper (II) nitrate trihydrate resulting in the formation of Cu‐TiO2/rGO. The Cu‐TiO2/rGO hybrid nanocomposite was fully characterized using spectroscopic and microscopic techniques. This study explored the versatility of the rotating ring‐disc electrode (RRDE) as an in situ electroanalytical tool for the selective detection of products formed during ERCO2. The well‐designed hybrid electrocatalyst, containing Cu0/Cu+ active sites, facilitated the eight‐electron transfer for acetic acid (AA) formation at low potentials. AA formation was detected on the RRDE and validated by conventional NMR and HPLC techniques. This work highlights and expands the scope of selective hydrogenation of CO2 towards value‐added products. [ABSTRACT FROM AUTHOR]

Nanofluid plays an important role in heat transfer engineering as a heat transfer medium. Therefore, we developed graphene oxide (GO)/carboxylated ferric tetroxide (Fe3O4–COOH) nanofluid with high stability using a two-step method. The preparation, characterization, physical properties and heat transfer properties of nanoparticles and nanofluids were investigated. The results show that GO/Fe3O4–COOH(GF) nanofluids present high stability at low concentrations (0.01 mass%, 0.05 mass% and 0.10 mass%) with absolute values of Zeta potential value greater than 30 mV. By adjusting the pH, it was found that GF nanofluids presented the best stability at pH = 10. A study of the physical properties of the nanofluids revealed that the viscosity of the GF nanofluids did not increase excessively with the addition of Fe3O4–COOH nanoparticles relative to the GO nanofluids. The heat transfer platform tests revealed that compared with the same concentration of GO nanofluids, the GF nanofluids have significantly higher heat dissipation efficiency. The temperature drop of 0.05 mass% GF nanofluid is higher than that of deionized water at the same pump power. We believe that well-stabilized GO nanofluids incorporating Fe3O4–COOH will provide more meaningful value in heat exchange than GO nanofluids. [ABSTRACT FROM AUTHOR]

There is an urgent need to accurately quantify microRNA (miRNA)-based Alzheimer's disease (AD) biomarkers, which have emerged as promising diagnostic biomarkers. In this study, we present a rapid and universal approach to establishing a target miRNA-triggered rolling circle amplification (RCA) detection strategy, which achieves ultrasensitive detection of several targets, including miR-let7a-5p, miR-34a-5p, miR-206-3p, miR-9-5p, miR-132-3p, miR-146a-5p, and miR-21-5p. Herein, the padlock probe contains three repeated signal strand binding regions and a target miRNA-specific region. The target miRNA-specific region captures miRNA, and then the padlock probe is circularized with the addition of T4 DNA ligase. Subsequently, an RCA reaction is triggered, and RCA products containing multiple signal strand binding regions are generated to trap abundant fluorescein-labeled signal strands. The addition of exonuclease III (Exo III) causes signal strand digestion and leads to RCA product recycling and liberation of fluorescein. Ultimately, graphene oxide (GO) does not absorb the liberated fluorescein because of poor mutual interaction. This method exhibited high specificity, sensitivity, repeatability, and stability toward let-7a, with a detection limit of 19.35 fM and a linear range of 50 fM to 5 nM. Moreover, it showed excellent applicability for recovering miRNAs in normal human serum. Our strategy was applied to detect miRNAs in the plasma of APP/PS1 mice, demonstrating its potential in the diagnosis of miRNA-associated disease and biochemical research. [ABSTRACT FROM AUTHOR]

The particular properties of graphene oxide (GO) make it a material with great technological potential, so it is of great interest to find renewable and eco-friendly sources to satisfy its future demand sustainably. Recently, agricultural waste has been identified as a potential raw material source for producing carbonaceous materials. This study explores the potential of cashew nut shell (CNS), a typically discarded by-product, as a renewable source for graphene oxide synthesis. Initially, deoiled cashew nut shells (DCNS) were submitted to pyrolysis to produce a carbonaceous material (Py-DCNS), with process optimization conducted through response surface methodology. Optimal conditions were identified as a pyrolysis temperature of 950 °C and a time of 1.8 h, yielding 29.09% Py-DCNS with an estimated purity of 82.55%, which increased to 91.9% post-washing. Using a modified Hummers method, the Py-DCNS was subsequently transformed into graphene oxide (GO-DCNS). Structural and functional analyses were carried out using FTIR spectroscopy, revealing the successful generation of GO-DCNS with characteristic oxygen-containing functional groups. Raman spectroscopy confirmed the formation of defects and layer separations in GO-DCNS compared to Py-DCNS, indicative of effective oxidation. The thermogravimetric analysis demonstrated distinct thermal decomposition stages for GO-DCNS, aligning with the expected behavior for graphene oxide. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) further corroborated the morphological and compositional transformation from DCNS to GO-DCNS, showcasing reduced particle size, increased porosity, and significant oxygen functional groups. The results underscore the viability of cashew nut shells as a sustainable precursor for graphene oxide production, offering an environmentally friendly alternative to conventional methods. This innovative approach addresses the waste management issue associated with cashew nut shells and contributes to developing high-value carbon materials with broad technological applications. [ABSTRACT FROM AUTHOR]