Search Results (159)

The pharmaceutical industry is a major source of pollution in wastewater effluents, characterized by chemical residues that are complex and difficult to degrade. Naproxen, a commonly detected drug in sewage effluents, exceeds safe concentrations for aquifers and is highly persistent, posing significant risks to aquatic life and ecosystems. This drug is known to cause long-term side effects in humans, such as gastrointestinal ulcers and nephrosis, associated with frequent and prolonged use. Additionally, the recent pandemic has led to a marked increase in drug consumption over a short period, exacerbating environmental contamination. Titanium dioxide has been extensively used as a photocatalyst in recent decades, proving effective in reducing these emerging pollutants. In this study, TiO₂ doped with cerium was synthesized using the sol–gel method, with cerium concentrations varied at 1, 3, 5, and 10% by weight. The resulting nanocatalysts were characterized through nitrogen physisorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-Vis diffuse reflectance spectroscopy. Photocatalytic activity was assessed using a UV-Vis spectrophotometer to monitor the degradation of the drugs. XRD analysis confirmed the crystallinity and anatase phase of TiO₂. UV-Vis diffuse reflectance spectra indicated a decrease in bandgap energy of up to 3.00 eV compared to pure TiO₂. The materials demonstrated significant degradation of naproxen (NPX) and acetaminophen (ACTP), both prepared at 30 ppm, over a 6 h reaction period. Full article

Cerium dioxide (CeO₂) has emerged as a structurally versatile oxide for dye-wastewater purification because its architecture, porosity, and surface accessibility can be tuned over a wide range while maintaining good chemical stability and environmental compatibility. Recent studies show that template-free or low-template routes can generate porous, mesoporous, multilayered, and flower-like CeO₂ architectures with rapid dye uptake and, in some systems, adsorption-assisted photocatalytic removal. However, CeO₂-based dye removal has often been discussed either within broad surveys of environmental applications or from composition-centered viewpoints, whereas the more fundamental question is how synthesis route controls architecture formation and how architecture, in turn, governs adsorption and subsequent removal behavior. This mini-review addresses that question from a morphology-centered perspective. It first examines template-free and low-template routes for constructing structured CeO₂, then discusses how porosity, hierarchical assembly, and surface accessibility regulate adsorption kinetics and equilibrium capacity in dye-containing aqueous systems. It further considers adsorption-assisted photocatalytic removal and argues that dark adsorption should be regarded as the structural first step rather than a secondary contribution. On this basis, the review shows that rare-earth doping in these systems is most usefully understood as a secondary tuning strategy that refines an already favorable host architecture by modifying surface interaction, optical response, or reactive-species generation. Overall, the available evidence indicates that CeO₂-based dye-wastewater purification is most meaningfully interpreted through a route–architecture–function framework in which morphology defines the host, adsorption organizes the local reaction environment, and doping serves mainly as structure-assisted tuning. This perspective shifts the design logic of CeO₂ from empirical performance optimization toward rational structure-directed construction of integrated removal platforms. Full article

Cerium oxide nanoparticles (CeO₂NPs) possess unique physicochemical properties that make them promising compounds for medical and industrial applications. However, variations in synthesis methods, particle size, and surface characteristics may influence their potential toxicity. This study provides a comparative analysis of CeO₂NPs synthesized via three methods (citric, dextran, and uncoated modifications) to evaluate their toxicity, antioxidant mechanisms, and genoprotective potential using a panel of Escherichia coli-based lux-biosensors. Our data indicate that all of the tested CeO₂NPs exhibit high biocompatibility with no significant toxicity or genotoxicity at physiological concentrations (10⁻⁴–10⁻² M). The citrate-modified nanoparticles demonstrated pronounced catalase-mimetic activity, acting as the most effective scavengers against hydrogen peroxide. Conversely, the dextran-modified nanoparticles exhibited the highest antimutagenic potential, reducing dioxidine-induced DNA damage by over 56%. Thus, beyond establishing biocompatibility, this study highlights the potential of using specific CeO₂NP modifications for targeted therapy depending on the oxidative pathway involved. This suggests their potential for application as antioxidant and antimutagenic agents in both human and veterinary medicine. Full article

This study presents a comprehensive comparative analysis of the performance, combustion, and emission characteristics of a single-cylinder, four-stroke spark-ignition engine fueled by commercial gasoline and raw biogas enhanced with cerium oxide (CeO₂) nanoparticles. Raw biogas containing 58% methane was tested without carbon dioxide removal to reflect practical rural applications, while CeO₂ nanoparticles were ultrasonically dispersed in the fuel to promote homogeneous suspension and catalytic activity. Experiments were conducted under wide-open and part-throttle conditions across a range of engine speeds, with simultaneous measurement of brake thermal efficiency, brake-specific fuel consumption, volumetric efficiency, in-cylinder pressure, heat release rate, combustion phasing, and regulated emissions. The results showed that while gasoline consistently outperformed biogas in torque and power due to its higher heating value and flame speed, the addition of CeO₂ significantly reduced the performance gap. For the biogas mode, CeO₂ addition increased brake thermal efficiency by up to 5%, lowered brake-specific fuel consumption by up to 8%, and shifted the start of main combustion to earlier crank angles, indicating faster and more complete combustion, particularly at high loads where higher temperatures activate CeO₂’s catalytic behavior. Emission analysis revealed that CeO₂-blended biogas reduced carbon monoxide emissions by approximately 25% and unburned hydrocarbons by up to 55% compared with gasoline, while nitrogen oxide emissions were consistently 15–22% lower. These reductions were observed across both wide-open and part-throttle conditions, confirming improved combustion completeness and lower peak flame temperatures. These improvements are attributed to CeO₂’s oxygen-storage capability, catalytic oxidation activity, and enhanced thermal conductivity, which collectively strengthen combustion completeness and cyclic stability. The findings demonstrate that nanoparticle-enhanced biogas can substantially improve the environmental and operational viability of spark-ignition engines, offering a practical pathway for integrating renewable gaseous fuels into existing transportation systems. Full article

Using pseudoboehmite and cerium nitrate as raw materials, a cerium dioxide-doped alumina support was prepared by the hot oil column method. Subsequently, with platinum nitrate and palladium nitrate solutions as precursor salts, the active components were loaded onto the supports via the incipient wetness impregnation, followed by an activation treatment, thus obtaining platinum-palladium bimetallic catalysts for hydrocarbon elimination in zero-air generators. The catalyst was characterized by XRD, BET, SEM, TEM, XPS, and Raman spectroscopy. The results showed that the as-prepared supports possess a large specific surface area, and the noble metals Pt and Pd are uniformly distributed on the support surface. After activation treatment, the structural stability and catalytic reaction activity of the catalysts are significantly enhanced. Performance tests simulating the actual operating conditions of zero-air generators show that the catalysts exhibit excellent hydrocarbon elimination capability: when the inlet methane concentration is 50 ppm, the outlet methane content can be reduced to below 10 ppb. Moreover, no obvious attenuation of catalyst activity is observed after a 1000-h long-term stability test, which meets the practical application requirements of zero-air generators. Full article

Nitrogen oxides (NO_x), carbon monoxide (CO), sulfur dioxide (SO₂), and volatile organic compounds (VOCs) in industrial waste gases pose significant threats to environmental quality and human health. Catalytic purification is recognized as a leading abatement technology, crucial for meeting increasingly stringent emission regulations. Rare-earth (RE) catalytic materials, particularly those based on cerium (Ce), lanthanum (La), praseodymium (Pr), and neodymium (Nd) oxides, have attracted intense research due to their unique electronic configurations, high oxygen storage capacity (OSC), facile reversible redox reactions Ce⁴⁺, Ce³⁺, and exceptional thermal stability. This paper provides a comprehensive and methodical overview of RE catalysts used in industrial waste-gas purification. Initially, the physicochemical characteristics of RE elements and their multifaceted roles as active phases, supports, and promoters are explained. Subsequently, the latest developments in RE-based catalysts for NO_x abatement, CO oxidation, VOC degradation, and the removal of sulfur-bearing gas are critically reviewed. The discussion emphasizes structure–activity relationships, reaction mechanisms, and the synergistic interactions between RE elements and transition metals. Comparative analyses are presented through tables focusing on catalyst composition, reaction conditions, performance parameters, and stability. Special attention is given to the enhanced resistance to water vapor and sulfur poisoning afforded by RE materials. Finally, current challenges and future research prospects, including cost reduction, scalability, and long-term durability, are suggested. This review aims to provide practical guidance for the rational design and industrial translation of next-generation RE catalytic materials for air pollution control. Full article

MXenes, a family of two-dimensional transition metal carbides and nitrides, exhibit exceptional electrical conductivity, tunable surface chemistry, and strong broadband light absorption. However, their practical implementation is often limited by structural instability, such as restacking and surface oxidation. In this study, we propose a strategy for the design of hybrid nanocomposites based on exfoliated Ti₃C₂T_x MXene embedded within a porous silica (SiO₂) matrix and further functionalized with cerium dioxide (CeO₂) nanoparticles. The SiO₂ matrix, synthesized via a sol–gel approach, ensures homogeneous dispersion, increased porosity, and thermal stability, effectively reducing MXene restacking. Simultaneously, CeO₂ nanoparticles create surface oxygen vacancies and enhance interfacial reactivity. Comprehensive structural, morphological, surface, and optical characterizations confirm the formation of stable, light-responsive nanoarchitectures with tailored textural properties. Furthermore, the obtained material exhibit promising photothermal-catalytic properties. This work offers a materials-oriented approach for engineering multifunctional MXene-based architectures with enhanced photothermal performance, exemplified by their potential application in the photothermo-catalytic CO₂ conversion into solar fuels, showcasing the broader possibilities enabled by these materials. 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

Corrosion in harsh environments causes global economic losses exceeding 3 trillion US dollars annually. Traditional silicone epoxy (SE) coatings are prone to failure due to insufficient physical barrier properties and lack of active protection. In this study, cerium dioxide (CeO₂) was in situ grown on the surface of hexagonal boron nitride (h-BN) mediated by polydopamine (PDA) to prepare BN-PDA-CeO₂ ternary nanocomposites, which were then incorporated into SE coatings to construct a multi-scale synergistic corrosion protection system. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) confirmed the successful preparation of the composites, where PDA inhibited the agglomeration of h-BN and CeO₂ was uniformly loaded. Electrochemical tests showed that the corrosion inhibition efficiency of the extract of this composite for 2024 aluminum alloy reached 99.96%. After immersing the composite coating in 3.5 wt% NaCl solution for 120 days, the coating resistance (Rc) and charge transfer resistance (Rct) reached 8.5 × 10⁹ Ω·cm² and 1.2 × 10¹⁰ Ω·cm², respectively, which were much higher than those of pure SE coatings and coatings filled with single/binary fillers. Density functional theory (DFT) calculations revealed the synergistic mechanisms: PDA enhanced interfacial dispersion (adsorption energy of −0.58 eV), CeO₂ captured Cl⁻ (adsorption energy of −4.22 eV), and Ce³⁺ formed a passive film. This study provides key technical and theoretical support for the design of long-term corrosion protection coatings in harsh environments such as marine and petrochemical industries. Full article

It is well known that nitrite is widely used in industrial and agricultural sectors as a preservative, corrosion inhibitor, and intermediate in chemical synthesis; consequently, nitrite residues are often present in food, water, and the environment as a result of meat curing, fertilizer use, and wastewater discharge. Despite having several applications, nitrite exerts toxic effects on human beings and aquatic life. Therefore, the monitoring of nitrite is of particular significance to avoid negative impacts on human health, the environment, and aquatic life. Previously, the electrochemical method has been extensively used for the development of nitrite sensors using various advanced electrode materials. Additionally, zinc oxide (ZnO), cerium oxide (CeO₂), titanium dioxide (TiO₂), copper oxide (CuO), iron oxides, nickel oxide (NiO), polymers, MXenes, reduced graphene oxide (rGO), carbon nanotubes (CNTs), graphitic carbon nitride (gCN), metal–organic frameworks (MOFs), and other composites have been utilized as electrocatalysts for the fabrication of nitrite electrochemical sensors. This review article provides an overview of the construction of nitrite sensors using advanced electrode materials. The electrochemical activities of the reported nitrite sensors are discussed. Furthermore, limitations and future perspectives regarding the determination of nitrite are discussed. Full article

Background/Objectives: This review summarizes and analyzes current data on the toxicological effects of cerium dioxide nanoparticles (nanoceria) on various anatomical and functional systems in healthy murine models, as reported in both in vivo and ex vivo experimental settings. Methods: This systematic review was conducted and reported in accordance with the PRISMA 2020 guidelines and was prospectively registered in PROSPERO (CRD42024503240). A systematic literature search was conducted using the PubMed and ScienceDirect databases for the period 2019–2025, with the inclusion of earlier publications having significant scientific relevance. The final search update was conducted in July 2025 to ensure inclusion of the most recent studies. Results and Conclusions: Only in vivo and ex vivo studies in healthy murine models were included. Risk of bias was evaluated using the OHAT tool for animal studies, and data were synthesized narratively due to heterogeneity among studies. A total of 29 studies met the inclusion criteria. The pharmacokinetic properties of nanoceria were considered, encompassing biodistribution, elimination pathways (including oral, intravenous, intraperitoneal, inhalation, intratracheal, and instillation routes), and the influence of physicochemical characteristics on bioavailability and toxicity. The toxicological impact (TI) was assessed across major organ systems—respiratory, digestive, urinary, visual, reproductive, nervous, cardiovascular, immune, hematopoietic, endocrine, musculoskeletal, and skin. The liver, spleen, lungs, and kidneys were identified as primary accumulation sites, with clearance dependent on particle size and coating. The TI spectrum ranged from the absence of morphological changes to inflammation, fibrosis, or organ dysfunction, depending on dose, exposure route, and physicochemical parameters. The main limitations include variability of nanoparticle formulations and incomplete toxicity reporting. In general, CeO₂ nanoparticles with sizes of 2–10 nm and doses ≤ 5 mg/kg showed no signs of systemic toxicity in short-term studies on healthy mice, provided that optimal coating and dosing intervals were used. Full article

A novel highly sensitive voltammetric sensor based on a glassy carbon electrode (GCE) modified with a mixture of cerium and tin dioxide nanoparticles (NPs) as a sensing layer was developed. Surfactants of various nature (anionic sodium dodecyl sulfate, cationic N-cetylpyridinium bromide, and non-ionic Triton X-100, Brij^® 35, and Tween-80) were used as dispersive agents for NPs. Complete suppression and a significant decrease in the dye oxidation peak occurred in the case of Tween-80 and sodium dodecyl sulfate, respectively. CeO₂–SnO₂ NPs in Brij^® 35 gave the best response to Acid Yellow 3 caused by its adsorption at the electrode surface. Linear dynamic ranges of 0.50–7.5 and 7.5–25 mg L⁻¹ with a detection limit of 0.13 mg L⁻¹ of Acid Yellow 3 were achieved using differential pulse mode in Britton–Robinson buffer pH 5.0. Full article

Cerium dioxide (CeO₂) nanoparticles with distinct morphologies, including rods, cubes, and octahedrons, were synthesized via a straightforward hydrothermal method. The microstructure and morphology of the as-prepared samples were systematically characterized. The antibacterial activity of the samples against Escherichia coli was evaluated using the plate counting method. The antibacterial experiments revealed that the antibacterial properties of the samples were arranged in the following order: rod > cube > octahedron. Data analysis indicated that the superior antibacterial performance of the CeO₂ nanorod was attributed to the higher concentration of oxygen vacancies and adsorption of reactive oxygen species (ROS) on the surface, with ROS playing a critical role in the antibacterial mechanism of CeO₂. Additionally, density functional theory (DFT) calculations were employed to simulate the oxygen vacancy environments of CeO₂ with different morphologies and provided indirect insights into ROS behavior. Combining experimental and computational results, a mechanistic framework was proposed to elucidate the dependence relationship between morphology and antibacterial activity of CeO₂. Full article

The tumor microenvironment (TME) is characterized by hypoxia; acidic pH; oxidative stress; and immune suppression; all of which severely impair the efficacy of conventional cancer therapies. Recent advances in inorganic nanotechnology have led to the development of smart nanomaterials capable of modulating these abnormal features; thereby reprogramming the TME toward a more therapy-responsive state. Inorganic nanomaterials such as manganese dioxide; iron oxide; and cerium oxide can selectively alleviate hypoxia; buffer acidity; regulate redox balance; and even stimulate anti-tumor immunity through catalytic or structural mechanisms. These materials can further serve as carriers for stimuli-responsive drug delivery; enabling synergistic therapies that include chemodynamic; photothermal; and immunomodulatory treatments. This review summarizes recent developments in smart inorganic nanomaterials for TME modulation; discusses design considerations including biosafety and biodegradability; and evaluates the current translational status and future directions. Such strategies represent a promising leap toward precise and personalized cancer nanomedicine Full article

Humidity sensing elements based on sodium-doped titanium dioxide (Na-doped TiO₂) were prepared using a sol–gel method in the presence of cerium ions and sintered at 400 °C and 800 °C. Titanium (IV) n-butoxide and a saturated solution of diammonium hexanitratocerate in isobutanol served as starting materials. Sodium hydroxide and sodium tert-butoxide were used as inorganic and organometallic sodium sources, respectively. The influence of sodium additives on the properties of the humidity sensing elements was systematically investigated. The surface morphologies of the obtained layers were examined by scanning electron microscopy (SEM). Elemental mapping was conducted by energy-dispersive X-ray (EDX) spectroscopy, and structural characterization was performed using X-ray diffractometry (XRD). Electrical properties were studied for samples sintered at different temperatures over a relative humidity range of 15% to 95% at 20 Hz and 25 °C. Experimental results indicate that sodium doping enhances humidity sensitivity compared to undoped reference samples. Incorporation of sodium additives increases the resistance variation range of the sensing elements, reaching over five orders of magnitude for samples sintered at 400 °C and four orders of magnitude for those sintered at 800 °C. Full article