Search Results (123)

To improve the wear resistance of 45 steel, nano-agglomerated Al₂O₃-TiO₂-CeO₂/carbon nanotubes (CNT) composite powders were prepared by spray drying and ball milling, followed by plasma spraying to fabricate coatings. The effect of CNT content on microstructure and wear resistance was investigated. The powders showed uniform size and high sphericity. Coatings mainly consisted of α-Al₂O₃, γ-Al₂O₃, and TiO₂. CNT addition refined grain size to 18.3 ± 1.1 nm. The high thermal conductivity of CNT reduced unmelted particles, improving coating density and element uniformity. Average coating thickness was 200 μm. When the CNT content reached 3 wt.%, the coating porosity decreased to 5.01 ± 0.72%. TEM analysis indicated that CeO₂ was mainly located at the grain boundaries. Moreover, the interfaces between CNT (002) and CeO₂ (220) appeared clean and well-bonded. As CNT content increased, microhardness and wear resistance first increased then decreased. At 3 wt.% CNT, the volumetric wear rate was 0.87 ± 0.15 × 10⁻⁵ mm³·N⁻¹·m⁻¹, representing an 8.46-times improvement in wear resistance compared to the substrate. The presence of CeO₂ enhanced the surface activity of CNT, facilitating the formation of lubricating films during friction and contributing to the superior wear resistance of the composite coating. Full article

In response to the harsh operating conditions of high-speed, high-temperature bearings in new energy vehicle drive motors, this study focuses on enhancing the performance of polyurea-based gel greases through the use of nano-additives. Using polyurea-based gel grease as the matrix, nano-composite gel greases with different CeO₂ loadings were prepared, and their tribological properties and rheological behavior were characterized using four-ball friction tests, rheological testing, and SEM analysis. The results indicate that adding 0.5 wt% CeO₂ increased the grease’s yield stress by approximately 75.4% and significantly raised its apparent viscosity. This rheological enhancement effect may be attributed to the physical adsorption of ultrafine particles onto the polyurea fiber network and potential interfacial interactions between the particles and the fiber surfaces. Compared to the original grease, the average coefficient of friction decreased by 10.4%, and the average wear scar diameter decreased by 12.7%. Meanwhile, the shear stress increased by 110.41 Pa, and the viscosity increased by 1102 Pa·s. This study provides experimental evidence and technical references for the development of high-performance gel lubricants suitable for motor bearings operating under high-temperature conditions. Full article

Plenty of nano-antimicrobial materials have been developed successively, aiming to address severe clinical challenges such as wound healing disorders and high postoperative mortality rates caused by drug-resistant bacterial infections. However, their reliance on external stimuli (light, thermal energy, or exogenous H₂O₂ addition) for bactericidal activation severely hampers clinical translation from bench to bedside. Herein, we report an engineered Cu/CeO₂ nanoplatelet (NP) system that functions as a stimulus-independent, time-dependent nano-antibiotic against methicillin-resistant Staphylococcus aureus (MRSA), while also exhibiting broad-spectrum antibacterial activity. In a skin wound model infected with MRSA, topical application of only 1 μg/mL achieved near-complete wound closure within 10 days. The satisfactory therapeutic effect is concluded: (1) Cu/CeO₂ NPs continuously release Cu²⁺, which damages the integrity of bacterial cell membranes and achieves efficient sterilization. (2) The antioxidant stress capacity, peroxidase, and catalase-like activity effectively alleviate oxidative stress and hypoxia conditions in the infected microenvironment, and synergistically exert multiple biological effects such as anti-inflammatory, promoting collagen deposition and the formation of new blood vessels. This study not only provides a feasible pathway for the clinical application of antibacterial nano-materials, but also offers theoretical support and practical examples for the rational design of multifunctional nano-antibiotics. Full article

Based on the E5018 zirconia–alkali low hydrogen iron powder electrode as the base composition, this paper incorporates nano-rare earth CeO₂ powder into the coating. Using the orthogonal experimental method, a total of nine groups of experiments were established, each with four factors and three levels. These factors include (A) nano-rare earth CeO₂ powder at levels of 1.1%, 1.3%, and 1.6%; (B) iron powder at levels of 30%, 35%, and 40%; (C) fluorite at levels of 6%, 8%, and 10%; and (D) zirconium quartz at levels of 5%, 7%, and 9%. The arc combustion stability of the welding rod is determined by an arc analyzer, and the formation and slag removal of the weld seam are evaluated by wide slope welding. Welding a spatter is evaluated by an observation method. The range and variance of the orthogonal experiment results were calculated, and the process performance was studied and analyzed. The results indicate that samples No. 1, 4, 5, 7, and 9 demonstrate superior performance in the welding process, specifically in terms of arc stability, weld formation, slag detachment, and spatter. The addition of nano-rare earth CeO₂ powder has the most significant impact on weld formation, while iron powder, fluorite, and zirconium quartz have notable effects on arc stability, spatter, and slag detachment, respectively. The optimal combination of these four factors at three levels for optimal welding process performance is A2B1C2D3, with the recommended amounts being 1.3% of nano-CeO₂ powder, 30% of the iron powders, 8% of fluorite, and 9% of zirconium quartz. Full article

CeO₂ is widely studied in catalysis owing to its Ce⁴⁺/Ce³⁺ redox couple and oxygen storage capacity (OSC), but its low-temperature redox activity remains a challenge. To address this, this study investigates the effects of saturated In³⁺ doping (1 mol.%) on the structural, redox, and catalytic properties of nano-octahedral CeO₂. Structural and chemical analyses reveal that In³⁺ doping induces lattice contraction from 5.4171 to 5.4129 Å, increases oxygen vacancy concentration from 29.7% to 39.8%, and raises surface Ce³⁺ fraction from 27.6% to 30.0%. Consequently, H₂-TPR measurements show that the surface reduction peak temperature decreases from 548 to 406 °C and the onset reduction temperature shifts from 309 °C to 183 °C. Quantitative OSC analysis further demonstrates that the low-temperature OSC increases from 13.17 to 20.57 mmol O₂/mol and the high-temperature OSC from 53.36 to 59.38 mmol O₂/mol upon doping. As a result of these enhancements, CO-TPSR tests reveal improved low-temperature CO oxidation performance, with the CO₂ light-off temperature decreasing from 99 to 72 °C and the rapid oxidation temperature from 153 to 96 °C. Notably, H₂O and H₂ signals are detected during CO-TPSR, and FTIR analysis confirms the enrichment of surface hydroxyl groups in the doped sample, offering new mechanistic insights into the involvement of surface species in the reaction pathway. Overall, saturated In³⁺ doping effectively enhances the oxygen vacancy concentration, surface reducibility, and CO oxidation activity of nano-octahedral CeO₂. Full article

Zinc-based coatings are insufficient as surface coatings; they corrode rapidly and can cause long-term damage to subsea pipelines and other instruments. Therefore, this research was undertaken by manufacturing a sacrificial nano-reinforced Zn coating combined with additives via electrodeposition onto a mild steel S235 substrate, which provides excellent corrosion resistance under severe marine conditions. The electrodeposited coatings were characterized using SEM/EDS and XRD, revealing the effective incorporation of cerium oxide nanoparticles and high-quality graphene (Gr) in the zinc matrix. Vickers microhardness measurements, mechanical resilience, and surface roughness of the Zn-CeO₂-Gr coating showed an inverse correlation between improved microhardness (+65.85%) and mechanical resilience (+31.49%), while surface roughness decreased (−81.48%) compared to pure zinc electrodeposited coatings. These characteristics indicate grain refinement and greater reliability under mechanical stress. Electrochemical impedance spectroscopy (EIS) and DC polarization measurements indicate a significant improvement in corrosion resistance compared to pure zinc, due to the synergistic effect between graphene and cerium oxide nanoparticles, which reduces the cathodic activity of the surface. These findings offer promising applications for cutting-edge materials in saline environments. Full article

Weathered crust elution-deposited rare earth ores represent a significant source of medium and heavy rare earth elements. Their mineralization mechanism fundamentally involves the adsorption and enrichment of rare earth ions on the surfaces of secondary minerals within the weathering crust. To elucidate the role of nano-sized iron oxide–clay mineral composites in the migration and enrichment of rare earth elements (REEs) in weathered crusts, α-Fe₂O₃, oolitic hematite, Fe₂O₃-kaolinite, and FeOOH-kaolinite composites were selected as adsorbents. Using La³⁺, Ce³⁺, and Y³⁺ as target ions, their adsorption performance and fractionation mechanisms were systematically investigated through batch adsorption experiments combined with characterization techniques including Langmuir/Freundlich model fitting, Zeta potential, XPS, and FT-IR. The results demonstrate that the adsorption of REEs on iron oxides and their composites follows the Langmuir model (R² > 0.96), indicating monolayer homogeneous adsorption. The FeOOH-kaolinite composite exhibited the highest adsorption capacity (0.6531 mmol/g for Ce). Amorphous iron oxide–clay mineral composites showed superior complexation adsorption and enrichment capabilities due to their higher oxygen vacancy concentration (Oβ/Oα = 3.86 for FeOOH-kaolinite), whereas crystalline iron oxide–clay mineral composites contributed significantly to REE fractionation and enrichment. Among the influencing factors, elevated temperature (20–60 °C) favored the adsorption process, with an activation energy > 4.2 kJ/mol indicating chemical adsorption dominance. Within the pH range of 3.0–7.0, adsorption capacity increased with rising pH, with Ce being more sensitive to ionic strength and pH variations. The adsorption mechanism was further elucidated through post-adsorption XPS, FT-IR in the low-wavenumber region, and desorption studies. This study confirms that iron oxide–clay mineral composites regulate the enrichment and fractionation of REEs in weathered crusts through the interplay of their surface properties and environmental factors, providing a scientific basis for refining the metallogenic theory and guiding the exploration and development of weathered crust elution-deposited rare earth ore resources. Full article

Nanotechnology holds great promise for alleviating drought stress in crops. This study elucidates and compares the distinct physiological mechanisms by which two nanomaterials, nano-cerium oxide (CeO₂) and nano-titanium dioxide (TiO₂), function as seed-priming agents to enhance drought tolerance in barley. A comprehensive analysis encompassing germination performance, hormonal dynamics, starch metabolism, osmotic adjustment, photosynthetic pigments, and the antioxidant system revealed that each nanomaterial operates through a unique pathway. Specifically, priming with 150 mg·L⁻¹ nano-CeO₂ (CP-150) primarily promoted root development and stress resilience. This effect was achieved by persistently reducing abscisic acid (ABA) levels, elevating gibberellin (GA₃), enhancing amylase activity to mobilize seed reserves, and increasing soluble protein accumulation in roots. In contrast, priming with 500 mg·L⁻¹ nano-TiO₂ (TP-500) was more effective in enhancing shoot physiology and adaptive capacity by rapidly inducing auxin (IAA), robustly stimulating the antioxidant enzyme system, and increasing photosynthetic pigment content. The temporally and spatially complementary actions of these nanomaterials, with nano-CeO₂ fostering root-based resilience and nano-TiO₂ boosting shoot-level functions, synergistically support seed germination and seedling establishment under drought conditions. This study provides a mechanistic foundation for designing targeted nano-priming strategies to improve crop drought resistance. Full article

There is an urgent need to evaluate the toxicity of xenobiotics and environmental mixtures for preventing loss in water quality for the sustainability of aquatic ecosystems. A simple prebiotic chemical pathway based on malate formation from pyruvate (pyr) and glyoxalate (glyox) is proposed as a quick and cheap screening tool for toxicity assessment. The assay is based on the pyr and glyox (aldol) condensation reactions, leading to biologically relevant precursors such as oxaloacetate and malate. Incubation of pyr and glyox at 40–70 °C in the presence of reduced iron Fe(II) led to malate formation following the first 3 h of incubation. The addition of various xenobiotics/contaminants (silver, copper, zinc, cerium IV, samarium III, dibutylphthalate, 1,3-diphenylguanidine, carbon-walled nanotube, nanoFe₂O₃ and polystyrene nanoparticles) led to inhibitions in malate synthesis at various degrees. Based on the concentration inhibiting malate concentrations by 20% (IC20), the following potencies were observed: silver < copper ~ 1.3-diphenylguanidine ~ carbon-walled nanotube < zinc ~ samarium < dibutylphthalate ~ samarium < Ce(IV) < nFeO₃ < polystyrene nanoplastics. The IC20 values were also significantly correlated with the reported trout acute lethality data, suggesting its potential as an alternative toxicity test. The pyr-glyox pathway was also tested on surface water extracts (C18), identifying the most contaminated sites from large cities and municipal wastewater effluents dispersion plume. The inhibition potencies of the selected test compounds revealed that not only pro-oxidants but also chemicals hindering enolate formation, nucleophilic attack of carbonyls and dehydration involved in aldol-condensation reactions were associated with toxicity. The pyr-glyox pathway is based on prebiotic chemical reactions during the emergence of life and represents a unique tool for identifying toxic compounds individually and in complex mixtures. Full article

This study examines the rheological and tribological behavior of bio-based nano-lubricants enhanced with cerium oxide (CeO₂) and multi-walled carbon nanotubes (MWCNTs), alongside the application of artificial intelligence (AI) models for performance prediction. Rheological results confirmed non-Newtonian, shear-thinning behavior across all formulations. CeO₂-based lubricants exhibited significantly higher viscosities at 40 °C (up to ~3700 mPa·s at low shear), which decreased sharply with shear, indicating strong particle interactions. In contrast, MWCNT-based lubricants maintained moderate viscosities (90–365 mPa·s at 40 °C) with improved flowability due to nanotube alignment. At 100 °C, both systems showed viscosity reduction, stabilizing between 8 and 18 mPa·s, which favors pumpability in high-temperature applications. Tribological testing revealed distinct performance characteristics. CeO₂ lubricants showed slightly higher coefficients of friction (0.144–0.169) but excellent wear resistance, achieving the lowest wear rate of 1.66 × 10⁻⁶ mm³/N-m. MWCNT-based lubricants offered stable and lower CoF values (0.116–0.148) while also providing very low wear rates, with MCO6 achieving 1.62 × 10⁻⁶ mm³/N-m. However, ternary blends (C20T80 and M20T80) displayed moderate CoF but significantly higher wear rates (up to 2.92 × 10⁻⁵ mm³/N-m), suggesting that blending improves dispersion but weakens tribo-film stability. To complement the experimental findings, support vector regression (SVR), artificial neural networks (ANN), and AdaBoost algorithms were employed to predict key performance parameters based on compositional and thermal input data. The models demonstrated high prediction accuracy, validating the feasibility of AI-driven formulation screening. These results highlight the complementary potential of CeO₂ and MWCNT additives for high-performance bio-lubricant development and emphasize the role of machine learning in accelerating material optimization for sustainable lubrication systems. Full article

Studies were conducted on the hydrogen-free processing of model alkanes, straight-run gasoline, and catalytic cracking gasoline using a new synthesized Co-Mo-Ce/ZSM + Al₂O₃ nanocatalyst, which demonstrated high activity in desulfurization. Thus, the mass fraction of sulfur in the resulting gasoline was reduced by almost three times compared to the initial value of 0.0776% to 0.0354% as a result of hydrogen-free processing of straight-run gasoline. The amount of sulfur in the resulting product was reduced by almost an order of magnitude with hydrogen-free processing of catalytic cracked gasoline: from 0.1650 in the original gasoline to 0.0123%. The octane number of the refined straight-run gasoline was 77.9–80.9 according to the research method (RM) and 61.13–65.8 with the motor method (MM). Physical and chemical methods of analysis (BET, TPD-NH₃, TEM, SEM, and XRD) revealed that nano-structured acid sites coexist with nano-dispersed metallic sites on the surface of the Co-Mo-Ce/ZSM + Al₂O₃ catalyst. The functioning of these two types of nano-active sites (metallic and acidic) ensures the polyfunctionality of the catalytic action of the nanoparticles. The following reactions occur simultaneously in the hydrogen-free processing: isomerization, dehydrogenation, dehydrocyclization. Hydrogen-free processing of low-octane gasoline fractions on nanosized zeolite-containing catalysts is one of the most promising methods to obtain high-octane motor gasoline. Full article

With the acceleration of industrialization, the demand for NO_x abatement is becoming increasingly urgent. Finding safer and more stable reducing agent replacements and efficient catalysts is crucial for selective catalytic reduction (SCR) industrial NO_x abatement. Low-temperature hydrocarbon-assisted NO_x reduction (HC-SCR) remains attractive for industrial abatement. A series of industrial-grade TiO₂ support catalysts modified with a bimetallic MnCe active component, represented as TiO₂-ig, was prepared by the impregnation method to test the NO conversion performance under a 200–400 °C window with C₃H₆ as a reducing agent, and the physical properties were characterized using the BET and XRF methods. Under the feed of 150 ppm NO, 150 ppm C₃H₆, and 3%O₂—the optimal composition—Mn₁₅Ce₁₀/TiO₂-ig catalyst exhibited the highest NO_x conversion of 77.3% among industrial-grade TiO₂ support catalysts, with the corresponding temperature reduced to 275 °C. Furthermore, a slight improvement in catalytic activity was observed upon changing the TiO₂ support type. The industrial-grade and nano-sized TiO₂ supports predominantly exhibited mesoporous structures, while the anatase TiO₂ support contained a greater proportion of macropores. A steady-state kinetic model constructed for Mn₁₅Ce₁₀/TiO₂-ig catalyst indicates that the NO reaction rate is independent of C₃H₆ and O₂ concentrations at 200 and 250 °C. At 300 °C, C₃H₆ inhibits the reaction, while both O₂ and NO promote it. Changes in activation energy and the pre-exponential factor suggest a mechanistic shift from adsorption-limited at lower temperatures to reaction-limited at higher temperatures. Overall, using industrial-grade TiO₂ with MnCe promoters delivers meaningful NO_x reduction in a low-temperature regime and provides kinetic insights relevant to process design for industrial C₃H₆-SCR. Full article

This study presents a comprehensive investigation into the large-scale production of synthetic and hybrid (nanoparticle-loaded) nanofibers using needleless electrospinning. A diverse range of polymers, including polyamide 6 (PA6) and its other polymer combinations, recycled PA6, polyamide 11 (PA11), polyamide 12 (PA12), polyvinyl butyral (PVB), polycaprolactone (PCL), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), polyurethane (PU), polyvinyl alcohol (PVA), and cellulose acetate (CA), were utilized to fabricate nanofibers with tailored properties such as polymer solution concentrations and various solvent systems. Furthermore, an extensive variety of nano- and micro-particles, including TiO₂, ZnO, MgO, CuO, Ag, graphene oxide, CeO₂, Er₂O₃, WO₃, MnO₂, and hyperbranched polymers, were incorporated into the polymeric systems to engineer multifunctional nanofibers with enhanced structural characteristics. The study examines the impact of polymer–nano/micro-particle interactions, fiber morphology, and the feasibility of large-scale production via needleless electrospinning. The resulting nanofibers exhibited diameters starting from 80 nm, depending on the polymer and processing conditions. The incorporation of TiO₂, CeO₂, WO₃, Ag, and ZnO nanoparticles into 15% PA6 solutions yielded well-dispersed hybrid nanofibers. By providing insights into polymer selection, nano- and micro-particle integration, and large-scale production techniques, this work establishes a versatile platform for scalable hybrid nanofiber fabrication, paving the way for innovative applications in nanotechnology and materials science. Full article

Yttria-stabilized zirconia(YSZ) was introduced into the Al₂O₃-TiO₂-CeO₂ coating prepared by plasma spraying to improve the wear resistance of the coating and prolong the service life of the weathering steel. The nano-agglomerated powder was prepared by mechanical ball milling and spray-drying technology, powder was sprayed on the surface of Q355 steel substrate by atmospheric plasma sparing (APS), the Al₂O₃-TiO₂-CeO₂/YSZ composite coating was prepared, and the effects of YSZ on the phase, microstructure, and tribological properties of the composite coating were studied. The results show that nano-agglomerated powders with micron size (average size 55 μm) can be prepared by spray-drying technology, and after high-temperature sintering, the nano-agglomerated powders are denser and form the α-Al₂O₃ phase. The composite coating prepared by plasma spraying has a bimodal structure, and after adding YSZ, the phases in the coating are mainly α-Al₂O₃, γ-Al₂O₃, and t-ZrO₂, the grain size is fine, and the porosity is reduced. The specific wear rate is only 4.4 × 10⁻⁵ mm³ N⁻¹·m⁻¹, the relative wear resistance is 6.3 times higher than that of the substrate, and the wear mechanism of the coating is mainly slight adhesive wear and abrasive wear, which shows excellent friction and wear properties at room temperature. Full article

Without changing any of its constituents, tyre pyrolysis oil energy (TPOE) has frequently been subjected to Diesel-RK (D-RK) analyses in diesel engines in an effort to serve as a substitute for diesel fuel. Environmentally beneficial TPOE features, such as biodegradability, renewability, and ease and safety of handling, are highly sought after. In addition to its beneficial aspects, TOPE also has drawbacks. The BTE and SFC of performance metrics, as well as the smoke and NO_x of emission parameters of alternative fuel, do not meet the emission limits specified by regulatory authorities. Nano-additions have been shown to be effective for boosting fuel quality for improved performance and production characteristics. In this study, TPOE–diesel blends are blended with ceramic oxide (CeO₂ of 50 and 100 ppm) nanoparticles and subjected to a performance and production investigation of engine working physiognomies in diesel engines. For the blend TPOE10CDF80 + D, the numerical results show a positive outcome of a 1.0% rise in BTE, a 2.0% decrease in SFC, a 17.7% decrease in smoke emission, and an 18.2% increase in NO_x emission as compared to diesel fuel (CDF). Full article