Search Results (423)

Eco-friendly lubricant manufacturing focuses on using biodegradable, renewable base oils, such as waste oil, and green-synthesized nanomaterials, such as agricultural residue-based nanoparticles, in order to replace conventional toxic lubricants with biodegradable alternatives and reduce environmental impact. These nanolubricants are produced through low-energy methods like mechanical, microwave, or chemical-free synthesis that can result in improvement in their performance. The produced lubricants exhibit enhanced tribological properties, including reduced friction and wear. Several formulations also raise the thermal degradation onset above that of their mineral benchmarks, although oxidative stability remains the weakest property of bio-based systems. This approach addresses industrial demands for sustainable, cost-effective, and environmentally compliant lubrication technologies. Our study reviews sustainable, eco-friendly synthesis methods for producing high-performance nanolubricants from different waste oils, including cooking and mineral oils. In addition to the incorporation of residue-based nanoparticles (e.g., eggshell) in waste oils, the performance and properties of bio-based lubricants with engineered nanoparticles, such as metal nano-oxides and carbon-based nanomaterials, are also reviewed for comparison purposes. Within bio-based fluids at moderate contact severity, residue-derived additives are found to match their engineered counterparts in terms of friction and wear, while engineered two-dimensional lamellar additives retain an advantage under extreme-pressure conditions where residue-derived particles have not yet been evaluated. Neither class has been assessed by life cycle or biodegradation testing as a finished formulation. Full article

Supercapacitors offer high power density, fast charging/discharging capability, and long cycle life, yet their relatively low energy density limits broader deployment in electric vehicles, portable electronics, and grid storage systems. MXenes, a family of two-dimensional transition metal carbides, nitrides, and carbonitrides, have emerged as promising electrode materials due to their high electrical conductivity, tunable surface chemistry, hydrophilicity and intrinsic pseudocapacitive behavior. However, restacking of MXene layers reduces accessible surface area and ion transport efficiency, constraining electrochemical performance. To address this limitation, MXene-based nanocomposites incorporating carbon nanomaterials, conducting polymers, and metal oxides have been extensively developed. This review systematically evaluates recent advances in MXene-based nanocomposites for high-energy-density supercapacitors, highlighting electrochemical performance. A quantitative benchmarking comparison with commonly used electrode materials, including graphene, carbon nanotubes, and activated carbon, is provided. Key challenges in synthesis, performance standardization, and stability are discussed, along with future prospects for developing safer and scalable production methods of MXene-based electrodes. 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

MXenes have emerged as a rapidly expanding family of two-dimensional transition-metal carbides, nitrides, and carbonitrides, characterized by exceptional compositional diversity, tunable surface chemistry, metallic conductivity, hydrophilicity, mechanical flexibility, and rich redox activity. These characteristics make MXenes highly attractive for next-generation technologies, including energy storage and conversion, catalysis, electromagnetic interference shielding, sensors, water purification, biomedical systems, and smart functional devices. However, the performance of MXene-based materials is strongly governed by their synthesis routes, defect structures, interlayer spacing, surface terminations, oxidation stability, and interfacial interactions with polymers, metals, oxides, and other two-dimensional materials. Therefore, a structure–property-oriented understanding is essential for moving MXene research from empirical material development toward rational functional design. Unlike application-centered summaries, this review develops a cross-application engineering framework that connects MXene synthesis and processing with multiscale structure, functional properties, performance trade-offs, and translational requirements. First, major synthesis and processing strategies are discussed, including selective etching, delamination, intercalation, surface modification, and scalable fabrication. Next, the relationships between MXene composition, morphology, surface chemistry, electrical conductivity, electrochemical behavior, mechanical properties, and environmental stability are analyzed. Recent advances in functionalization, heterostructure construction, and composite engineering are then highlighted to illustrate how MXene properties can be tailored for emerging applications. Finally, key challenges related to oxidation, restacking, long-term stability, environmental safety, reproducibility, and industrial translation are critically evaluated. This review aims to establish a design framework for engineering MXene nanomaterials toward high-performance, stable, and scalable emerging technologies. Full article

Exosomes and small extracellular vesicles are promising liquid-biopsy biomarkers because they carry molecular information from their cells of origin and can be accessed from minimally invasive biofluids. Reliable separation and detection are made more difficult by their small size, low abundance, diverse composition, and co-occurrence with lipoproteins, protein aggregates, and other extracellular particles. To improve exosome enrichment, capture, and sensing, nanomaterial-assisted techniques have become crucial. Using a mechanism-based approach that differentiates between non-gravimetric signal amplification and genuine physical mass loading, this study offers an organized comparison of nanomaterial-enabled exosome sensing techniques. This distinction is helpful because different transducers measure different physical quantities: while optical, electrochemical, fluorescent, catalytic, and nucleic acid-based platforms typically benefit from enhanced signal generation rather than increased mass, resonant and gravimetric sensors benefit from increased inertial or surface-bound mass. In terms of amplification mechanism, transducer compatibility, sample-matrix tolerance, workflow complexity, and translational maturity, the review contrasts metallic nanoparticles, magnetic systems, metal–organic frameworks, carbon and two-dimensional materials, quantum dots, upconversion nanomaterials, DNA nanostructures, and polymer-based platforms. The gap between analytical sensitivity and clinical utility, including separation purity, recovery, biological heterogeneity, pre-analytical variability, interference from complex biofluids, and the need for uniform validation, is given special focus. The review concludes that no single nanomaterial or amplification method is universally optimal; instead, platform-aware, application-specific integration of isolation, amplification, and validation techniques is necessary for clinically meaningful exosome sensing. Full article

Exhaled breath analysis has emerged as a promising non-invasive approach for disease diagnosis, leveraging gas sensors for their high sensitivity, portability, and real-time monitoring capabilities. Two-dimensional nanomaterials, such as graphene, transition metal dichalcogenides (TMDs), MXenes, black phosphorus, and metal–organic frameworks (MOFs), exhibit exceptional gas-sensing properties due to their atomic-scale thickness, ultra-large specific surface area, and tunable electronic structures. These characteristics enable enhanced gas adsorption and room-temperature operation, making them ideal for detecting ppb-level biomarkers like acetone, ammonia, and nitric oxide in breath. However, sensors based on pristine 2D materials face challenges including slow response/recovery kinetics, poor stability, weak humidity resistance, and limited selectivity in complex breath environments. To address these limitations, functionalization strategies have been developed to engineer material properties. Key approaches include heteroatom doping to modulate electronic band structures, heterojunction construction to facilitate charge transfer and improve selectivity, and noble metal decoration for catalytic enhancement of gas adsorption. Additionally, light irradiation has been employed to regulate the carrier concentration on the surface of sensitive materials. These strategies significantly boost sensor performance, achieving ppb-level detection limits, robust humidity resistance, and rapid response. Future directions involve integrating functionalized 2D materials into wearable, multiplexed sensor arrays for simultaneous biomarker detection, coupled with machine learning for real-time diagnostic platforms. Full article

Fe₃O₄ magnetic nanoparticles, as typical magnetic nanomaterials, can be functionalized and self-assembled into one-dimensional and two-dimensional structures to obtain new physicochemical properties. However, there are few studies on preparing stable large-sized one-dimensional Fe₃O₄ magnetic nanochains structure by a simple self-assembly method, and its application scope needs to be expanded urgently. In this paper, a large-size Fe₃O₄@SiO₂ one-dimensional nanochains were synthesized and modified by means of different functionalization. On this basis, the application of one-dimensional nanochains in the flow injection chemiluminescence analysis was explored. Glucose oxidase was immobilized on the Fe₃O₄@SiO₂ nanochains, which as a packed stationary phase, was successfully coupled with the flow injection system through the optimization of experimental conditions. As a result, a novel flow injection chemiluminescence analysis of glucose was developed. It has been proven that the one-dimensional nanochains-based packed stationary phase not only retains similar catalytic sites as the free magnetic particles, but also effectively overcomes the problem of poor fluidity of the free fixed phase. Therefore, it is expected to explore more high-performance flow injection analysis systems by strategies of the nanochain-immobilized enzyme-based packed stationary phase. Full article

Two-dimensional nanomaterials exhibit excellent physical barrier properties, which can effectively enhance the corrosion resistance of waterborne epoxy coatings. Herein, we report a facile strategy for preparing a multi-component synergistic anti-corrosion coating, where two-dimensional graphitic carbon nitride (g-C₃N₄) and high-entropy layered double hydroxides (HE-LDHs) are integrated into a waterborne epoxy matrix via magnetic-ultrasonic synergistic dispersion. The resulting HE-LDHs/g-C₃N₄-epoxy coating exhibits exceptional corrosion resistance for Q235 steel. Electrochemical impedance spectroscopy (EIS) and polarization curves showed that when the mass ratio of g-C₃N₄ to HE-LDHs was 1:1, the resulting coating (PCN-LDH-1.0) maintained a coating resistance of 5.48 × 10⁵ Ω·m² after 28 days of immersion in 3.5% NaCl solution, which was five orders of magnitude higher than that of pure waterborne epoxy coating. Meanwhile, the corrosion current density was reduced by four orders of magnitude, from 5.83 × 10⁻¹ A·m⁻² to 1.68 × 10⁻⁵ A·m⁻². After 30 days of salt spray testing, no rust, blistering or adhesion loss was observed on the coating surface. These enhanced performances by addition of g-C₃N₄ and HE-LDHs were attributed to the combined effects of the tortuous diffusion pathways. Additionally, the PCN-LDH-1.0 coating retained excellent mechanical properties, including a pencil hardness of 3H and the highest adhesion grade. This study provides a facile method for preparing high-performance waterborne anti-corrosion coatings. Full article

Municipal solid waste incineration fly ash (MSWI FA) represents a significant environmental challenge due to its high content of toxic heavy metal (HM) and large-scale generation. This study demonstrates the feasibility pathway for converting hazardous MSWI FA into well-crystallized layered double hydroxide nanosheets (LDH-FA). Sodium dimethyl dithiocarbamate (SDD) was incorporated as a chelating stabilizer to enable synergistic HM immobilization during acid leaching and crystallization. High-resolution transmission electron microscopy (HRTEM) confirmed the characteristic two-dimensional nanosheet morphology with interlayer spacings consistent with LDH structures, while elemental mapping revealed homogeneous distribution of Pb and Zn within the nanosheet matrix. SDD dosages higher than 1.0 wt% effectively suppressed HM leaching, and Pb concentrations were controlled below 0.1 mg/L and Zn maintained at minimal levels. BCR sequential extraction analysis further demonstrated that SDD treatment effectively transformed HMs from bioavailable acid-soluble fractions to stable forms. This investigation establishes an innovative approach to MSWI FA resource utilization and provides mechanistic insights into HM stabilization within LDH nanostructures, offering a scientific basis for safer applications of waste-derived nanomaterials. Full article

Freshwater scarcity driven by population growth and industrial demand has increased reliance on desalination, where reverse osmosis (RO) is widely applied due to its high separation efficiency. Membrane performance is governed by the balance between water permeability and solute rejection, and attempts to improve this relationship have focused on incorporating nanomaterials to modify membrane structure and transport behavior. In this study, a computational investigation was carried out for thin-film composite (TFC) membranes incorporating graphene oxide–poly(amidoamine) (GO–PAMAM) within the polysulfone substrate to examine its influence on transport under RO conditions. A two-dimensional model was implemented in COMSOL Multiphysics by coupling the Laminar Flow and Transport of Diluted Species interfaces, while permeation across the membrane was described using a solution–diffusion framework parameterized by experimentally determined salt permeability coefficient. Variation in GO–PAMAM loading (0–0.10 wt%) was introduced through intrinsic permeability parameters, enabling direct comparison with experimental data. The simulations reproduced the observed trends, with the membrane containing 0.06 wt% GO–PAMAM showing higher salt rejection, increasing from 78.16% to 90.08% relative to the pristine membrane. The model predicted lower permeate-side solute concentration and a decrease in salt rejection along the membrane length. Model predictions agreed with experiments, with mean relative errors of 1.23% for salt rejection and 7.41% for water flux, demonstrating the ability of the model to capture transport behavior in GO–PAMAM-modified TFC membranes. Full article

This study presents a hierarchical conductive-network strategy to overcome the performance trade-off in cement structural supercapacitors (CSSCs). By incorporating one-dimensional carbon nanotubes (CNTs) and two-dimensional graphene oxide (GO) into Portland cement, we simultaneously enhance its electrochemical and mechanical properties. The approach exploits the complementary roles of the two nanomaterials: CNTs establish a three-dimensional percolation network that facilitates electron transport, while GO promotes formation of a denser calcium silicate hydrate (C-S-H) gel and refines the pore structure by complexing with calcium ions, thereby improving ionic pathways. The k12gc sample attains a specific capacitance of 66.8 F g⁻¹ at 0.1 mA cm⁻², a 58.4% rise in conductivity and a 63% reduction in charge-transfer resistance. At the same time, the composite reduces harmful macropores by 27.9% and strengthens the material, with compressive and flexural strengths increasing by 4.8% and 8.3%, respectively. This work establishes a rational design principle based on functional division between CNTs and GO for developing high-performance, multifunctional CSSCs. Full article

MXenes are an emerging class of two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides with a unique combination of mechanical, electrical, and thermal properties. While MXenes have been extensively studied in electrochemical and materials science contexts, their mechanical behavior and engineering relevance remain comparatively underexplored. This paper provides a mechanically focused synthesis of MXene research, connecting structure, synthesis, processing, mechanical properties, and functional performance to engineering applications. Emphasis is placed on the tunability of tensile, elastic, shear, and thermomechanical properties through controlled variation of composition, surface terminations, and defects. Comparisons with graphene are used to clarify performance trade-offs and application-specific advantages. Key challenges, including environmental stability, moisture sensitivity, durability, scalability, cost, and integration with conventional engineering materials, are critically examined alongside current mitigation strategies. Applications in structural composites, mechanical reinforcement, energy storage, electromechanical systems, and MXene-based sensors and actuators are discussed to demonstrate practical relevance. By framing MXenes as engineerable materials rather than isolated nanomaterials, this work serves as a technical reference and entry point for mechanical engineers and interdisciplinary researchers seeking to design and deploy MXenes in advanced engineering systems. Full article

Innovations in nanomaterial science, engineering and printing technologies have increasingly driven advances in electrochemical sensing. Screen-printed electrodes (SPEs) have become a versatile, low-cost, and scalable solution for developing portable electrochemical detection platforms. However, their analytical performance remains intrinsically limited by surface area, electron transfer efficiency, and the immobilization of biomolecules. Recent developments in nanostructured materials, ranging from two-dimensional (2D) materials such as graphene, MXenes, and transition metal dichalcogenides, to one-dimensional nanostructures and hybrid nanocomposites, have transformed the signal transduction landscape of SPE-based electrochemical sensors. Integration of nanomaterials into SPEs has successfully transformed their analytical capabilities, but the diversity of materials and modification strategies has made it difficult to consolidate current knowledge in the field. Strategies that integrate nanomaterials via ink formulation, surface modification, or in situ growth have yielded sensors with unprecedented sensitivity, reproducibility, and selectivity across various chemical and biological targets. This review offers a cross-material synthesis of how nanomaterial engineering transforms the electrochemical performance of SPEs. By integrating insights across morphology, interfacial chemistry, and device-level behavior, it establishes a unified perspective that has been missing from the current literature and clarifies the design principles driving next-generation SPE-based sensing platforms. Full article

Transmission electron microscopy (TEM) is an essential technique for characterizing nanomaterials. However, specimen preparation, which is a critical factor affecting image quality, remains a practical challenge. Focusing on nanopowders used in materials and chemical science, this article employs case studies to analyze the key steps in TEM specimen preparation. Carbon support films (CSFs) are essential tools for specimen preparation, and this study introduces several commonly used, cost-effective options, including conventional CSFs, conventional holey CSFs, ultrathin holey CSFs, and double-grid support films. We characterize their structural and morphological characteristics and evaluate their suitability for different types of samples. Several representative case studies of nanopowders, spanning from zero-dimensional (0D) to one-dimensional (1D) and two-dimensional (2D) materials, are used to illustrate tailored specimen preparation approaches, which serve as practical references for researchers conducting TEM characterization. These findings facilitate higher image reliability and experimental efficiency, thereby providing critical support for advancing fundamental exploration and frontier innovation in nanomaterial science. Full article

Dopamine (DA) is a crucial catecholamine neurotransmitter, and its abnormal levels are closely associated with neurological disorders such as Parkinson’s disease. Electrochemical sensing technology offers a rapid and cost-effective platform for DA detection; however, it often suffers from interference from coexisting biomolecules such as ascorbic acid (AA) and uric acid (UA). In this study, we report a novel electrochemical biosensor based on PdMo bimetallene, a nanomaterial synthesized via a facile wet-chemical approach, aiming to enhance the detection performance and selectivity for DA. PdMo bimetallene is a highly curved, atomically thin two-dimensional nanosheet featuring abundant strained sites and a high density of active centers, enabling the selective and sensitive detection of DA. The results demonstrate that the as-prepared PdMo bimetallene-modified glassy carbon electrode (GCE) exhibits excellent electrocatalytic activity toward the oxidation of DA. The sensor displays a good linear response over the concentration range from 10 nM to 200 µM, with an ultrahigh sensitivity of 80 µA·µM⁻¹ cm⁻² and a low detection limit of 0.14 µM (S/N = 3). Owing to the synergistic electronic effect between Pd and Mo, the high density of exposed active sites, and the unique strained lattice structure of the bimetallene, the sensor enables accurate determination of DA concentrations even in the presence of interfering species such as AA and UA. In summary, the successfully fabricated PdMo bimetallene-based sensor offers the advantages of low cost, facile synthesis, a wide linear range, and high sensitivity, positioning it as a promising candidate for neurotransmitter detection applications. Full article