Search Results (1,450)

This work systematically investigates the optical behaviors of cesium lead bromide perovskite quantum dots (CsPbBr₃ PeQDs) functionalized with reduced graphene oxide (RGO) at varying reduction levels, and further explores their feasibility as emissive layers (EMLs) in quantum dot light-emitting diodes (QLEDs). Four batches of RGO with tunable reduction degrees were synthesized by adjusting the amounts of ammonia solution and hydrazine hydrate added, followed by the fabrication of RGO@CsPbBr₃ hybrids via an in situ hot-injection method. Experimental characterizations reveal that the photoluminescence quantum yield (PLQY) of the as-prepared RGO@CsPbBr₃ composites can be precisely modulated from 45% to 65% by tuning the reduction degree of RGO. Using the optimized RGO@CsPbBr₃ sample, multilayer QLEDs with the architecture of indium tin oxide (ITO)/PEDOT:PSS/Poly-TPD/TAPC/RGO@CsPbBr₃/TPBi/Al were fabricated. Electroluminescence (EL) measurements show that the optimized device exhibits a turn-on voltage of approximately 3 V and a characteristic emission peak at 513 nm. Compared with devices based solely on bare CsPbBr₃ PeQDs, the composite-based QLED displays a slight blue shift in emission wavelength and enhanced electroluminescence intensity, which is attributed to the localized surface plasmon resonance effect induced by the RGO nanosheets. This work presents a reliable strategy to optimize perovskite hybrid optics for light-emitting applications. Full article

Peripheral nerve injuries are common traumas that are difficult to overcome. Although nerve grafting can quickly recover nearly all sensitivity and function, graft availability remains an issue. Research has focused on ways to directly rebuild and promote the healing of damaged nerves using surgically implanted scaffolds. Nerve regeneration can be further promoted through strategies aimed at enhancing the regenerative microenvironment, such as improving the electrical conductivity of nerve guidance conduits. In this study, composite films of chitosan (Ch) and carboxymethyl cellulose (CMC) nanofibers were prepared. To improve the films’ conductivity, reduced graphene oxide (RGO) was added. Structural analysis indicated interactions between Ch and CMC and showed that incorporation of RGO did not produce additional detectable crystalline phases. ChCMCRGO films showed slightly higher conductivity and greater surface hydrophilicity than ChCMC membranes and supported greater neurite outgrowth. Full article

Alkaline water electrolysis (AWE) is a promising technology for sustainable hydrogen production, although its performance is limited by electrode overpotential, interfacial charge-transfer resistance, and limited electrochemically accessible surface area. In this study, a monolayer ternary carbon nanomaterial (CNM) composite comprising reduced graphene oxide (rGO), carbon nanotubes (CNTs), and Vulcan XC-72 was fabricated on stainless steel (SS) using a hybrid polyvinyl alcohol–polytetrafluoroethylene (PVA–PTFE) binder. Thermal treatment generated a porous conductive network that enhanced electrolyte accessibility and electron transport. Electrochemical characterization in 0.12 M NaOH showed that the CNM-modified electrode exhibited substantially higher current response and CV-derived double-layer capacitance (C_dl) of 62.61–78.51 mF/cm², compared with 3.43–3.74 mF/cm² for bare SS. Electrochemical fitting further showed markedly higher exchange-current density (i₀) parameters for the modified electrode, along with a reduced solution resistance (Rs) of ~2.1–2.2 Ω·cm² and a lower Rct. The oxyhydrogen (HHO) production rate reached 0.304 mL/min at 3.8 V, compared with 0.262 mL/min for bare SS at 4.0 V. Repeated HHO measurements showed ~2% variation (n = 3), indicating good reproducibility of the gas-production response. These results demonstrate that the rGO/CNT/XC-72 composite provides an effective and reproducible surface-engineering approach for enhancing electrochemical performance and HHO production in alkaline electrolysis systems. Full article

Aluminum and its alloys feature low weight and high strength. They are widely applied in aerospace, automobile manufacturing, and marine engineering. However, they are highly susceptible to localized corrosion. Such defects can severely restrict the service life of the substrate materials. Pristine graphene exhibits atomic-level compact impermeability, stable chemical inertness, and excellent mechanical properties. It is a promising candidate material for the protection of aluminum substrates. Nevertheless, an electrically insulating interlayer is generally required between pristine graphene and aluminum to achieve reliable protection. This measure avoids the risk of galvanic corrosion. This paper systematically reviews the latest research progress of graphene-based coatings on aluminum, focusing on pristine graphene, graphene oxide (GO), reduced graphene oxide (rGO), and graphene-polymer composite coatings. It focuses on the preparation methods and corrosion protection performance of the materials. This study compares various mainstream preparation technologies in detail. The technologies include chemical vapor deposition, electrochemical deposition, mechanical exfoliation, solution coating, laser induction, and thermal spraying. The corrosion protection mechanism is discussed from three dimensions. The dimensions include physical barrier effect, tortuous path mechanism, and electrochemical protection. Key influencing factors, such as coating defects and environmental conditions, are also investigated. This paper summarizes the application potential of graphene-based coated aluminum in high-end manufacturing fields. It points out the major existing challenges of the material. The challenges involve coating uniformity, adhesion strength, long-term stability, and industrial production. Finally, future research directions are proposed in this work. These directions include the development of innovative coating technologies, the construction of composite protection systems, the design of intelligent self-healing functions, and the exploration of environmentally friendly preparation processes. Full article

To address cathode passivation, performance deterioration, and toxic stress during the removal of hexavalent chromium [Cr(VI)] in biocathode microbial fuel cells (MFCs), this study constructed nanomaterial-hybridized biocathodes to improve electricity generation and Cr(VI) removal in MFCs. Reduced graphene oxide (rGO), nano-iron sulfide (nano-FeS), and rGO/nano-FeS were separately hybridized with biocathodes to systematically investigate the effects of different hybridized biocathodes on the performance of MFCs for Cr(VI)-containing wastewater treatment. The results showed that the FeS group exhibited the best Cr(VI) removal capability, with a maximum removal kinetic constant of 0.184 h⁻¹, which was 3.60 times that of the Control group, and showed the smallest performance decline after three consecutive cycles. Mechanistic analysis indicated that nano-FeS promoted the transformation of Cr(VI) into Cr(III) and Cr(0) through its strong adsorption and reducing capacities; it also enhanced biofilm cell activity and the protein/polysaccharide ratio in extracellular polymeric substances; furthermore, it shaped a multi-taxon-dominated microbial community capable of Cr(VI) tolerance and reduction and enhanced the associated metabolic functions, thereby improving resistance to Cr(VI) stress and effectively alleviating cathode passivation. In contrast, rGO tended to enhance biocathode conductivity and electricity generation in MFCs, with the rGO + FeS group achieving the highest power density output of 51.54 ± 3.62 mW/m², which was 1.22 times that of the Control group, as well as the smallest decline in power density after three consecutive cycles. Overall, nanomaterial hybridization reshaped interfacial electron transfer and microbial stress resistance in biocathodes, enabling efficient Cr(VI) removal and stable electricity generation, and providing a new strategy to construct long-term stable bioelectrochemical systems for heavy metal-containing wastewater treatment. Full article

This study reports the synthesis and comprehensive characterization of a novel 5% cadmium-doped cerium oxide/reduced graphene oxide (5% Cd-CeO₂/rGO) nanocomposite for the enhanced visible-light-driven photocatalytic degradation of methyl orange (MO). The nanocomposite was prepared using a simple co-precipitation method followed by thermal reduction, which integrates the excellent electron-transport properties of reduced graphene oxide (rGO) with the oxygen-vacancy-rich characteristics of Cd-doped CeO₂, resulting in improved photocatalytic performance. The successful synthesis of the nanocomposite and the direct interaction between the rGO sheets and ultrafine CeO₂ nanoparticles were verified through structural and morphological analyses using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). XPS results indicated an increase in the Ce³⁺ concentration and oxygen vacancy density after Cd doping and rGO incorporation, both of which play a crucial role in enhancing photocatalytic activity. Under visible-light irradiation, the 5% Cd-CeO₂/rGO nanocomposite exhibited substantially higher photocatalytic activity and methyl orange (MO) degradation efficiency than pristine CeO₂ and reduced graphene oxide (rGO). The improved photocatalytic performance demonstrates the beneficial role of combining metal-ion doping with conductive carbon supports to facilitate charge separation and electron transport in semiconductor photocatalysts. The developed nanocomposite also shows promising potential for the design of next-generation semiconductor-based materials for photocatalytic, energy conversion, and optoelectronic applications. Full article

Metal–organic bimetallic frameworks of Ni–Co, having metal content of 2:1 and 1:2 molar ratios, respectively, have been synthesized via a rapid laser method with a continuous-wave Nd:YVO₄ laser (λ = 975 nm) under 88–90 °C in a DMF/H₂O solution in 70 min. The structure, porosity, and photophysical, electrochemical, and dielectric characteristics of the frameworks and their reduced graphene oxide (rGO) composites in the form of powders and UV-cured PEGMEA/PEGDA films have been investigated. Framework Ni2Co1MOF demonstrated a BET surface area equal to 88.3 m² g⁻¹ and a total pore volume of 0.022 cm³ g⁻¹, whereas framework Ni1Co2MOF exhibited a BET surface area of 52.5 m² g⁻¹ and a total pore volume of 0.016 cm³ g⁻¹. The incorporation of rGO from 1 to 10 wt.% into the framework changed the charge transport and polarization properties of the materials. The electrochemical investigations of the 10 wt.% rGO-Ni1Co2MOF composite in 0.5 M HCl demonstrated a specific capacitance of 32.3 F g⁻¹ at 10 mV s⁻¹, and it preserved 98% of the electrochemical response after 400 cycles, in comparison with 96% for the 10 wt.% rGO-Ni2Co1MOF. The electrochemical responses consisted of both diffusion-controlled ion transport and pseudocapacitance. The introduction of rGO in 1 to 10 wt.% in the polymer composite improved the conductivity and Maxwell–Wagner–Sillars interface polarization at low frequencies in the case of low rGO concentrations, whereas overly high rGO content led to aggregation and the decreased influence of the conductive phase. The main contribution of the present work is the fast sub-100 °C synthesis approach for compositionally tunable Ni-Co frameworks/rGO materials and the relationships between the metal ratio, porous structure, interfacial charge transport, and dielectric response. Full article

In this study, a novel SiC/rGO nanocomposite-modified glassy carbon electrode (SiC/rGO/GCE) was developed as a simple, cost-effective, and efficient electrochemical platform for metronidazole (MTZ) detection. The combination of silicon carbide (SiC) and reduced graphene oxide (rGO) provides a favorable interface with a high electroactive surface area, efficient electron transfer, and enhanced electrocatalytic activity. The mor-phology and surface characteristics of the modified electrode were investigated by scan-ning electron microscopy (SEM), while its electrochemical properties were evaluated by cyclic voltammetry and electrochemical impedance spectroscopy. The results confirmed successful electrode modification and improved electron-transfer kinetics compared with the bare GCE. The main experimental parameters were systematically optimized, with the optimum conditions established at pH 10, an accumulation time of 300 s, and an accu-mulation potential of 0.5 V. Under these conditions, the SiC/rGO/GCE exhibited a broad linear response to MTZ over the concentration range of 5–5000 µmol/dm³, with a detection limit of 0.5 µmol/dm³ (S/N ≥ 3). The enhanced analytical performance is attributed to the synergistic contribution of rGO and SiC, where rGO promotes rapid electron transport and provides a large electroactive surface, while SiC contributes additional active sites and structural stability. The sensor was successfully applied to pharmaceutical samples, providing recoveries of 99.85–102.29% with RSD values below 2%. These results demon-strate the practical potential of the proposed sensor for reliable MTZ determination. Fur-ther validation in food and biological matrices and comparison with reference chromato-graphic methods will be necessary to establish its broader analytical applicability. Full article

A composite based on humic acid (HA) and reduced graphene oxide (rGO) was synthesized to evaluate the effect of rGO on the structural, functional, thermal, and preliminary phenol adsorption properties of humic acid. The incorporation of rGO increased the carbon content from 47.34 to 55.61 wt.% and decreased the oxygen content from 48.31 to 40.79 wt.%. At the same time, the total content of carboxyl and phenolic hydroxyl groups increased from 5.00 to 5.47 mmol/g, indicating improved accessibility of oxygen-containing functional sites. FTIR spectroscopy confirmed the retention of the main functional groups of the initial components after composite formation. Thermogravimetric analysis showed enhanced thermal stability, with the residual mass at 1000 °C increasing from 59.21 to 70.03%. Electron microscopy revealed the formation of a developed wrinkled surface morphology. Preliminary phenol adsorption experiments showed that the HA-rGO composite exhibited higher adsorption capacity than the initial HA and rGO. This improvement was attributed to the combined contribution of oxygen-containing functional groups and the aromatic carbon structure of rGO, which may promote hydrogen bonding and π–π interactions with phenol molecules. Full article

Graphene oxide (GO) and reduced graphene oxide (rGO) are widely studied two-dimensional carbon nanomaterials for optoelectronic devices. Because the oxygen content and degree of reduction govern the electronic structure of GO-derived films, controlling the reduction process is essential for tailoring their properties. Laser-induced reduction provides a tunable, contact-free route to transparent and conductive graphene-based layers. In this work, 80 nm spray-coated GO layers were reduced using a KrF excimer laser (248 nm, 20 ns) at a fluence of 20 mJ cm⁻², while systematically varying the number of laser pulses (LP) from 1 to 1000. We tuned the degree of GO reduction by stepwise increasing the number of LP and followed the resulting changes in surface composition using X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine-structure (NEXAFS) spectroscopy. The surface composition evolves non-monotonically with the number of laser pulses, revealing a multi-step reduction mechanism. At low laser doses, epoxide groups are preferentially removed or converted, generating a more disordered distribution of hydroxyl-containing sites on the GO sheets. At intermediate laser doses, oxygen-containing groups are depleted, and sp² conjugation is restored. After extended irradiation in air, however, oxygenated surface species partially re-form. Conductivity measurements show that the sheet resistance reaches a minimum at approximately 300 LP, consistent with efficient chemical reduction and recovery of the conjugated carbon network. These results provide molecular-level guidelines for optimizing laser-induced GO reduction toward graphene-based transparent conductive layers. Full article

Titanium dioxide (TiO₂) photocatalysis is a promising sustainable solution for water decontamination; however, the industrial application of TiO₂ is hindered by its wide band gap and high handling and recovery costs. This work proposes to overcome these issues by developing a composite coating of nanopowder TiO₂ and reduced graphene oxide (rGO) applied onto commercial polyurethane (PU) foams by means of a simple, low-energy dip-coating process designed to enhance pollutant adsorption and photocatalytic activity. The rGO-TiO₂ coating was optimized by exploring different surface pre-treatments of the PU foams, the deposition of rGO-TiO₂ multilayers, and the variation in the rGO-TiO₂ mass ratio (1:3, 1:4, and 1:5). The prepared materials were characterized by optical microscopy, SEM-EDX, DSC, and thermogravimetry, while the stability of the coating was preliminarily evaluated through ultrasonic tests. The water decontamination capability of the coated foams was investigated by adsorption and UV-Vis photodegradation tests using a 3 mg/L aqueous solution of Rhodamine B (RhB) as a model contaminant. The results demonstrated that the rGO-TiO₂ 1:3-coated samples achieved complete RhB photodegradation within 90 min, with a pseudo-first-order kinetic constant of 0.0446 1/min. Moreover, pre-treating the foam with a 3 M NaOH solution improved coating adhesion onto the PU substrate while maintaining comparable decontamination efficiency. Full article

In the present work, graphene-modified zinc oxide (ZnO-rGO) and fluorine-doped tin oxide (FTO) thin films were successfully fabricated using a simple, low-cost pulsed spray pyrolysis technique. The structural, morphological, optical, electrical, and surface electronic properties of the deposited films were systematically characterized. X-ray diffraction (XRD) analysis confirmed the formation of polycrystalline ZnO- and SnO₂-based phases with crystallite sizes in the nanometer range. The crystallographic parameters, microstrain, and dislocation density of the deposited films were found to be influenced by the incorporation of reduced graphene oxide (rGO) and fluorine dopants. Scanning electron microscopy (SEM) revealed compact and homogeneous surface morphologies with good film coverage and well-defined nanocrystalline features. Optical characterization demonstrated the wide-bandgap semiconducting behavior of the deposited films, with optical bandgap energies ranging from 3.262 to 3.312 eV for the ZnO-rGO films and from 3.91 to 4.01 eV for the FTO films. Kelvin probe measurements yielded work-function values in the range of approximately 5.0–5.2 eV, indicating favorable surface electronic characteristics suitable for optoelectronic applications. Furthermore, fluorine incorporation enhanced the dielectric response of the SnO₂ films, particularly in the low-frequency region owing to increased interfacial polarization effects. The obtained results demonstrate that pulsed spray pyrolysis provides a simple, cost-effective, and efficient route for fabricating ZnO-rGO and FTO thin films with desirable structural, optical, electrical, and surface electronic properties. These findings highlight the considerable potential of the developed materials for transparent electrodes and a wide range of optoelectronic applications. Full article

Waterborne poly(vinyl alcohol) (PVA) adhesives are widely used in iodine-based polarizers, owing to their excellent transparency and interfacial adhesion. However, the intrinsic hydrophilicity of PVA compromises the long-term durability of polarizers under humid conditions. Herein, graphene derivatives with tunable oxygen contents and graphitization degrees, including graphene oxide (GO), partially reduced graphene oxide (rGO), and graphene nanosheets (GNs), were incorporated into a PVA/PEI adhesive system to investigate the oxygen-content-dependent interfacial interactions and moisture-barrier mechanisms. Structural analyses reveal that oxygen-rich GO enhances interfacial hydrogen bonding and polymer–graphene interactions, whereas highly graphitized GN primarily functions through its intrinsic lamellar barrier effect by increasing diffusion tortuosity and reducing water affinity. The rGO exhibits a compromise between interfacial interactions and barrier effects due to its moderate oxygen content and preserved graphene structure. Among them, the GN-modified adhesive demonstrates the most favorable overall performances, achieving a 14.71% reduction in the water vapor transmission rate (WVTR) of the assembled polarizer, enhanced moisture resistance, and improved antistatic capability while maintaining acceptable optical transparency. Furthermore, practical polarizer evaluations confirm that GN effectively suppresses moisture penetration, with only slight bubbling observed after 8 days of water immersion and no delamination or polarization degradation during a 40-day immersion test. These findings provide insights into the relationship between graphene oxygen content, interfacial interactions, and moisture-barrier behavior, offering an effective strategy for designing durable multifunctional waterborne adhesives for advanced optoelectronic polarizer applications. Full article

Composite aerogels based on polytetrafluoroethylene (PTFE) and graphene oxide (GO) with a high polymer content of 90, 95 and 98 wt.% were synthesized for the first time. It was found that GO performs a structure-forming function, allowing the production of monolithic three-dimensional frameworks stable under freeze-drying conditions even at a minimal concentration of 2 wt.%, whereas pure PTFE is destroyed under these conditions. Subsequent annealing of the composites at 370 °C, which is higher than the decomposition temperature of oxygen-containing groups of GO and the melting point of PTFE, leads to the formation of PTFE/reduced graphene oxide (rGO) aerogels. A direct dependence of shrinkage during annealing on the polymer content was observed: it sharply increases from 2.1% to 26.6% with an increasing proportion of PTFE. This effect is explained by the dominant role of capillary forces pulling together the rGO sheets in the molten polymer, while the rGO frame resists the shrinkage. The most significant result is the achievement of a record low water sorption capacity (Q_w) for an aerogel with 98% PTFE, amounting to only 0.001 g/g. This value is several orders of magnitude lower than that of pure rGO aerogel (~20 g/g), confirming that a high content of hydrophobic polymer combined with thermal treatment effectively shields the hydrophilic sites on the surface of the rGO sheets. The composites obtained in this work exhibit high hydrophobicity (contact angles up to 144°) and unique potential for the selective absorption of organic solvents from water. Full article

The growing global energy demand and increasing environmental concerns have created the need for the development of efficient, safe, and sustainable energy storage technologies. While lithium-ion batteries (LIBs) have dominated the energy storage market due to their high energy density and long cycle life, concerns regarding lithium resource scarcity, high cost, and safety risks associated with flammable organic electrolytes have motivated research on alternative batteries. In this context, aqueous zinc-ion batteries (AZIBs) have attracted significant attention as a promising next-generation energy storage system because of their inherent safety, resulting from the utilization of non-flammable aqueous electrolytes, and environmental friendliness, as well as natural abundance and low cost of zinc. Nevertheless, they face various challenges, which hinder their practical applications. Among them, the intrinsic limitations of the cathode materials, including their poor electronic conductivity, sluggish reaction kinetics and structural degradation during charge–discharge cycles, are considered particularly significant. Thus, the scientific community has explored various mitigation strategies, including the combination of cathode materials with carbon-based nanomaterials, such as reduced graphene oxide (rGO), with exceptional physicochemical properties. The present critical review discusses the most recent scientific work published in the literature during the last three years, referring to the combination of rGO with conventional cathode materials, such as manganese-based oxides, vanadium-based oxides, Prussian blue analogues, etc., for the development of next-generation AZIBs with superior electrochemical performance, long-term cycling durability, intrinsic safety, and enhanced sustainability. Full article