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Cerium oxide (CeO${}_2)$ and yttrium oxide (Y₂O${}_3)$ nanoparticles possess interesting surface properties and interfacial interactions that make them attractive candidates for various applications. This study presents a comprehensive investigation into the synthesis and toxicity assessment of yttrium-doped cerium oxide (Ce-Y) nanocomposite using a combination of analytical techniques and biological assays. The nanocomposite was characterized using UV–Vis spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), electron microscopy imaging, dynamic light scattering (DLS), and zeta potential measurements to elucidate their structural, optical and physicochemical properties. The synthesized nanocomposite exhibited distinctive absorption spectra and precise alignment of diffraction peaks, confirming the successful incorporation of yttrium ions into the cerium oxide lattice. Electron microscopy images revealed well-dispersed yttrium particles within the ceria matrix, indicating uniform distribution and morphology. DLS and zeta potential analysis provided insights into the size distribution and stability of the nanocomposite. Furthermore, in vivo toxicity assessment using Drosophila melanogaster model revealed no significant toxicity of Ce:Y nanocomposite, as evidenced by survival assay and behavioral assays. Superoxide dismutase (SOD) activity and reactive oxygen species (ROS) levels were also evaluated, demonstrating no discernible nanoparticle-induced toxicity. Overall, this study highlights the potential applications of Ce:Y nanocomposite and underscores the importance of comprehensive toxicity evaluation in nanomaterial development.

${\mathrm{\text{TiO}}}_2$ nanomaterials with different content of ${\mathrm{\text{Ce}}}^{4+}$ ion were synthesized by the chemical method from solutions and demonstrated improved photocatalytic and optical properties with significant redshift compared to pristine ${\mathrm{\text{TiO}}}_2$. According to X-ray phase analysis and transmission electron microscopy, all synthesized materials are characterized by anatase modification, which holds up to $800^{\circ }$C, the particle size for all materials is 12–21 nm. X-ray diffraction spectra revealed that the anatase to rutile phase transition for materials doped with ${\mathrm{\text{Ce}}}^{4+}$ ions begins at a higher temperature of $800^{\circ }$C compared to pristine ${\mathrm{\text{TiO}}}_2$. The influence of synthesis conditions and ${\mathrm{\text{Ce}}}^{4+}$ content (0.1–2 mol.%) on characteristics and photocatalytic activity were investigated. The Ce-doped ${\mathrm{\text{TiO}}}_2$ nanomaterial, containing 0.1% ${\mathrm{\text{Ce}}}^{4+}$ provides an extremely high degree of methylene blue decomposition by 93% within visible light irradiation for 3 h. The stability of the catalyst over four cycles has been shown, which makes it possible to use it in the purification of water resources from dyes or other pollutants.

The graphite nodule density and size distribution are two very important parameters in the characterization of the microstructures of ductile iron. Various amount of cerium element (Ce) (from 0.005% to 0.020%) were added into ductile iron cast in sand moulds to investigate the effect of Ce concentration on graphite nodule count and size distribution. The addition of Ce has a significant effect on solidified microstructures of ductile iron. Increasing of Ce concentration from 0.005% to 0.014%, an obvious increase in nodule graphite amount is achieved and graphite size becomes finer. When the addition level of Ce reaches 0.018% or 0.020%, spheroidal graphite begins to coarsen, resulting in the decrease in graphite amount and formation of the some non-spherical graphite. An evident nucleus and faceted crystals inside a nodule are clearly distinguished and the thin flakes that constitute the nodule are observed from the SEM photograph. EDX-analysis of nucleus of the spheroidal graphite shows that it is composed of sulfur, cerium, magnesium and trace calcium. The 3-D nodule count of ductile iron is 11.7 × 10³/mm³ with 0.005% Ce addition. The value is 45.8 × 10³/mm³ with Ce addition up to 0.014% and the majority of diameter is less than 30 µm. However, with 0.018%Ce residual, the nodule count decreases to 29.0 × 10³/mm³. The value is close to that of 0.018%Ce when Ce concentration is 0.020%, and the majority of diameter is less than 40 µm. The results indicate that the graphite nodule count reaches the maximum and mean diameter reaches the minimum with 0.014%Ce residual existing in ductile iron.

A detailed study of the effect caused by the partial substitution of Er by Ce on fluctuation conductivity of the Er_1-xCe_xBa₂Cu₃O_7-δ; 0 ≤ x ≤ 0.10; is presented. The combined experimental results of structural and electrical measurements indicate that Ce substitutes Er for x ≤ 0.10 with no significant structural distortions. However, there is suppression of the superconducting state with zero-resistance state at temperatures ≥ 86.3 K. The results were analyzed in terms of the temperature derivative of the resistivity and the logarithmic temperature derivative of the conductivity to identify power-law divergences of the conductivity. The data revealed the occurrence of a two-stage intragranular-intergranular transition. Above the critical temperature, the Gaussian and critical regimes were observed. Also, from the critical exponents analysis, we observed a splitting of the pairing transition for Ce-doped samples, suggesting the occurrence of a phase separation. On approaching the zero resistance state, our results showed a power-law behavior that corresponds to a phase transition from a paracoherent to a coherent state of the granular array and which does not depend on Ce doping.

We successfully obtained Ni–B and Ni–B–Ce coatings with and without sonication on low-carbon steel (Q235) through electroless plating with the deposition time of 60min. The surface morphology and elemental composition of the coatings were evaluated by scanning electron microscopy (SEM) and inductively coupled plasma (ICP). The 11$\mu$m thick sonicated Ni–B–Ce (Son-Ni–B–Ce) coating is uniform with the composition of Ni 87.1%, B 6.2% and Ce 6.6%. X-ray diffraction (XRD) measurements implied a typical broaden peak around 44^∘, considered as amorphous structure which was confirmed by selected area electron diffraction pattern (SAED). Atomic force microscopy (AFM) showed a typical circular pit of Ni–B–Ce coating and Son-Ni–B–Ce coating. X-ray photoelectron spectroscopy (XPS) revealed the chemical status of coating components. The mechanical and corrosion resistance properties were determined by Vickers hardness tester, potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS) in 3.5wt. % NaCl solution. As a result, the Son-Ni–B–Ce coating revealed the optimum hardness (956HV), minimum roughness $R_a$ (92.38nm) and excellent corrosion resistance (3.65$\mu$Acm${}^{-2})$ among all coatings.

The synergistic effect of Ce${}^{3+}$ and SiO₂ nanoparticles (NPs) composite silane film on the corrosion resistance of carbon steel was researched. The preparation method of silane film is mainly hydrolysis of bis-1,2-(triethoxysilyl)ethane (BTSE) and 3-glycidoxypropyltrimethoxysilane (KH-560) under acidic conditions and condensation reaction. EDX and SEM were employed to analyze the element distribution and morphological characteristics of the coating, which confirmed the coatings were crack-free and even distribution of surface elements. The chemical bond structure characteristics of the silane film on carbon steel were analyzed by XPS, and compared with the silane film after ultrasound. It proved the bonding force of the silane film. The best corrosion current density of the silane film containing cerium is 4.65 $\mu$Acm${}^{-2}$. The $R_{\mathrm{\text{ct}}}$ obtained by simulating the corrosion circuit through Zsimpwin software is 22.02k$\mathrm{\Omega }$cm${}^{-2}$. On this basis, by adding different concentrations of SiO₂ NPs, the corrosion current density can reach a minimum of 0.70 $\mu$Acm${}^{-2}$. The simulated polarization curve $R_{\mathrm{\text{ct}}}$ was 65.13k$\mathrm{\Omega }$cm${}^{-2}$. In the long-term open-circuit potential test, the potential of the silane film containing rare earth cerium increased to 38mV at a certain stage, which proves the self-healing performance of the film.

The optical and electrochemical properties of novel double-decker cerium bis-tetra-15-crown-5-phthalocyaninate [Ce(R₄Pc²⁻)₂]⁰ (R₄Pc²⁻ = [4,5,4',5',4",5",4'",5'"-tetrakis-(1,4,7,10,13-pentaoxapentadecamethylene)-phthalocyaninate-anion]) Langmuir-Blodgett and cast films were investigated. The particular feature of cerium ion in complex with tetra-15-crown-5-phthalocyanine is the stability of oxidation state +4 unlike other lanthanide metal centers. Cyclic voltammetry curves exhibited three stable redox states in the Langmuir-Blodgett and cast films. Redox processes in Langmuir-Blodgett films are reversible and reproducible at multiple scan procedures. The mechanisms of redox transformations in Langmuir-Blodgett films are suggested. We demonstrated that the well-defined structure of Langmuir-Blodgett film is essential for fast electron transfer within the planar system, in which the charge is delocalized along the conjugated assembly of uniformly ordered stacks of discotic crown-phthalocyaninate. Fast charge relaxation was observed in highly ordered Langmuir-Blodgett film whereas the electrochemically written redox states remained unchanged in unordered cast film. The combination of electrochemistry with surface plasmon resonance spectroscopy allowed us to demonstrate that stepwise change of potential in the range 200-850 mV induced the respective optical response, which can be observed as the change in resonance angle value. High-speed response and reversibility of the switching process between stable states may be utilized as the basis for switchable optoelectronic devices. Electrochemical multistability of cerium crown-phthalocyaninate provided a basis for developing a simple strategy to fabricate nanoelectromechanical systems with high efficiency and fast response. Our approach relies on the modulation of the distance between decks in a complex stack via redox-controlled change of metal center size that results in change of linear dimensions of the stacks. The reported results are valuable, not only because of their potential applications, for instance, in OFET and MEMS fabrication, but also from a fundamental point of view since they illustrate the interplay between the orientation of stacks bearing discotic aromatic molecules and charge transfer within such a planar assembly.

Redox properties of the title complex [Ce(pc)₂] (where pc denotes phthalocyaninate dianion, C₃₂H₁₆N₈^2-) have been investigated in dichloromethane solutions by cyclic- and rotating-disk-electrode voltammetry. Unlike the other rare-earth(III) analogs that show one oxidation and one reduction waves in the potential range of -1 – +1 V vs. the half-wave potential of the redox couple of ferrocene (Fc⁺/Fc), only the cerium(IV) derivative shows two oxidation and one reduction waves in the same potential range. The first and second oxidation and the first reduction waves have been assigned as pc^2-pc^•-/pc^2-pc^2-, pc^•-pc^•-/pc^2-pc^•-, and Ce^IV/III(pc^2-)₂, respectively, on the basis of spectroelectrochemical works. The ligand-centered electron-transfer processes are fully reversible and diffusion-controlled whereas the first reduction alone is quasi-reversible. Comparison of absorption and magnetic circular dichroism spectra before and after the metal-centered reduction suggests that structural change upon the electron-transfer is not significant in solution apart from the interplanar distance between the two macrocyclic ligands.

This is a comparative study of supercapacitor performance of CeO₂/PANI composite electrode prepared by two different synthesis methods, namely, in situ polymerization and solution mixing. The chemical composition of materials was confirmed by X-ray diffraction (XRD). The electrochemical studies such as cyclic voltammetry (CV), charge–discharge, electrochemical impedance and cyclic test of the composite were studied in two symmetrical electrode systems in an aqueous electrolyte medium. The CeO₂/PANI (CP10) composite prepared by in situ polymerization has resulted in better specific capacitance than solution mixing in an aqueous electrolyte (0.5M H₂SO₄) with the capacitance value of 240F/g at 0.5A/g. The in-situ polymerization method evenly spreads polyaniline (PANI) all over the cerium oxide (CeO₂) material and reduces charge transfer resistance ($R_{\mathrm{\text{ct}}}$) which is lacking in the solution mixing method. After 4000 cycles at 5A/g, the CP10 composite retained 72.8% of capacitance retention and energy density of 33.33Wh/Kg at power density of 249.87W/Kg.

Metal- and metal-oxide-based nanoparticles have been widely exploited in cancer photodynamic therapy (PDT). Among these materials, cerium-based nanoparticles have drawn extensive attention due to their superior biosafety and distinctive physicochemical properties, especially the reversible transition between the valence states of Ce(III) and Ce(IV). In this review, the recent advances in the use of cerium-based nanoparticles as novel photosensitizers for cancer PDT are discussed, and the activation mechanisms for electron transfer to generate singlet oxygen are presented. In addition, the types of cerium-based nanoparticles used for PDT of cancer are summarized. Finally, the challenges and prospects of clinical translations of cerium-based nanoparticles are briefly addressed.

This study investigates the impact of rare elements on high-entropy alloys (HEAs) and provides significant insights. By integrating varying proportions of Al-Nd and Al-Ce compounds into a CoCrFeNi-based alloy, shifts were detected in the microstructure and phase composition of grains. As the proportion of rare elements rose, their localization within the grain phase structure intensified, leading to overall coarsening. The heat transfer characteristics of HEA alloys containing rare elements exhibited variability, with notable phase transitions occurring at cryogenic temperatures based on the alloying constituents. Among the tested alloys, Ce10 and Ce20 alloys demonstrated the highest heat transfer rates (800${\text{Wg}}^{-1}$). Notably, an escalation in the rare element ratio added to the alloy resulted in a significant augmentation in hardness, nearly doubling the original level.

Metal- and metal-oxide-based nanoparticles have been widely exploited in cancer photodynamic therapy (PDT). Among these materials, cerium-based nanoparticles have drawn extensive attention due to their superior biosafety and distinctive physicochemical properties, especially the reversible transition between the valence states of Ce(III) and Ce(IV). In this review, the recent advances in the use of cerium-based nanoparticles as novel photosensitizers for cancer PDT are discussed, and the activation mechanisms for electron transfer to generate singlet oxygen are presented. In addition, the types of cerium-based nano-particles used for PDT of cancer are summarized. Finally, the challenges and prospects of clinical translations of cerium-based nanoparticles are briefly addressed.

In the chemistry conversion of the solution of CeCl₃–NaCl, the concentration of Cl^- affects the property of cerium-based conversion coating. Hence, we have ascertained the most appropriate concentration of Cl^- in the paper. Firstly, to prepare a cerium-based conversion coating in the solution of CeCl₃–NaCl on ZM–C5 alloy, we conducted the experiment by the simple immersion method. Secondly, the mass of the specimen was measured with a BS224S electronic scale. Finally, the corrosion resistance of the coating was evaluated by the dropping test. The results show that when the concentration of Cl^- is between 0 to 15 g·dm^–3, the smoothness, compactness and adhesion of the conversion coatings are better and that the most appropriate concentration of Cl^- is 10 g·dm^–3 by the dropping test. The conclusion can be drawn that the corrosion resistance of the coating is best by the simple immersion method in the solution which the concentration of cerium chloride is 3 g·dm_–3 and the concentration of sodium chloride is 10 g·dm_–3.

Gamma rays emitted by fission fragments of ²⁵²Cf and measured using the Gammasphere array continue to give insight into neutron rich nuclei. Using our high statistics data, we have reexamined high-spin states and linking transitions associated with octupole correlations in ¹⁴⁴Ba and ¹⁴⁸Ce. In an even-A system, it is possible that rotational band structures are explainable by simplex quantum numbers, s = +1 and s = -1. In ¹⁴⁴Ba and 148Ce we have deduced spin values from angular correlations and assigned parities from mixing ratios for s = -1 characterized states. These are the first examples of both simplex bands in even-even nuclei. Extensions to higher spins of bands in ¹⁴⁴Ba and in ¹⁴⁸Ce are also reported. In addition to collective model analysis of energy displacement and rotational frequency, the intrinsic dipole moment via B(E2)/B(E1) ratios are also analyzed.