Ce Ions Research Articles

Mn-Ce solid solution growth on Mn2O3 surface to form heterostructure catalysts with multiple active sites for toluene degradation

A solid solution-heterostructure catalyst with abundant active sites was successfully constructed in this study by in situ growth of Mn-Ce solid solution on the surface of Mn2O3. The solid solution structures with optimum physical and chemical properties were synthesized initially by controlling the Mn-Ce ratios. Subsequently, the reaction time was controlled to realize the orderly growth of the solid solution on the Mn2O3 surface. The catalyst (M−CeMn0.5) with solid solution-heterostructure formed by the reaction of Ce3Mn1 and Mn2O3 for 0.5 h could reach more than 90 % toluene degradation rate at 183 °C and was operated continuously for 15 h without deactivation. XRD showed that the appropriate reaction time resulted in the active components on the catalyst surface exhibiting lower crystallinity and reduced grain size. The reduction capacity (2.28 → 10.47 mmol/g) and the mobility of lattice oxygen were significantly enhanced in the M−CeMn0.5 catalyst compared to the Mn-Ce solid solution. Meanwhile, a high content of low valent metal ions (Ce3+/Ce4+ 0.33, Mn3+/Mn4+ 1.64) and reactive oxygen species (Oads/Olatt 0.53) were also present on the catalyst surface. The DFT demonstrated that the Mn atoms and Mn-O bridge sites on the solid solution surface exhibited high adsorption energy values for toluene (−0.8402/-0.8406 eV) and oxygen (−1.6546/-1.661 eV) molecules. The TEM indicated that lattice distortion and oxygen vacancies were formed at the interface between the solid solution and Mn2O3 at the interface. The synergy of multiple active sites favors the generation of reactive oxygen species and thus promotes p-methyl dehydrogenation. Meanwhile, the high mobility of lattice oxygen facilitates the breakage of benzene ring. This study provides a new strategy for the synthesis of efficient Mn-Ce-based catalysts.

Functionalized flattened bamboo board: In-situ immersion assembly of flame-retardant, waterproof and anti-mold composite coatings

The flattened bamboo board (FB) represents a promising innovation in the bamboo industry. To address the challenges of flammability and hygroscopicity, composite coatings consisting of melamine (MEL), phytic acid (PA), cerium ions (Ce3+), and sodium laurate (La) are assembled on the FB surface through an in-situ impregnation strategy. The resulting MEL/PA-Ce3+@La FB exhibits exceptional flame retardancy. It achieves a V-0 rating in the vertical burning test (UL-94) and boasts a high limiting oxygen index (LOI) value of 38.5 %. The coated FB exhibits superhydrophobicity, evidenced by a water contact angle of 156.5°, which can be attributed to the in-situ growth of PA-Ce3+ complexes (for constructing micro/nanoscale coarse structures) and the modification with La (for reducing surface energy).This superhydrophobic surface imparts both self-cleaning and anti-mold properties to the coated FB. Moreover, the coated FB exhibits excellent mechanical stability, withstanding 36 cycles of sandpaper abrasion and tape peeling without losing its hydrophobicity. In summary, this work provides an innovative strategy for the bamboo processing industry to produce flattened bamboo boards with combined flame retardancy, superhydrophobic and anti-mold properties. Such versatility holds significant potential to facilitate the utilization of flattened bamboo boards in the construction and decorative materials industries.

(Dielectric Science and Technology Division Poster Award, 1st Place) Effects of Gas Dissolved Water for Ceria Nanoparticles on the SiO2 Film Surface in Post-CMP Cleaning

In the semiconductor industry, there is a growing trend of using smaller ceria nanoparticles (CNPs) during the Swallow Trench Isolation (STI) CMP process. However, the use of these CNPs has made it more difficult to clean residual particles from the SiO2 film surface after CMP. This study aimed to investigate the effects of gas-dissolved water (GDW) on CNP surfaces and the mechanical cleaning effects of nucleated bubbles applying megasonic conditions. The study found that CNP surface was reduced by H2 GDW and CO2 GDW, but oxidized by O2 GDW. The concentration of Ce3+ ions on CNP surfaces changed from 18.64% to 19.48%, from 20.31% to 21.94%, and from 21.27% to 19.22% when CNPs were respectively immersed in H2 GDW, CO2 GDW, and O2 GDW for 3 to 12 hours. Adhesion energy between CNPs and SiO2 particle surface, following immersion of CNPs in H2 GDW, CO2 GDW, and O2 GDW for 6 hours, was found to be 6.06E-16 J, 6.18E-16 J, and 4.83E-16 J, respectively. After cleaning with GDW and applying megasonic, residual Ce ion concentrations on the SiO2 film surface were found to be 0.06 ppb, 0.41 ppb, and 0.10 ppb for H2 GDW, CO2 GDW, and O2 GDW, respectively.

Yttrium doped cerium oxide as free radical scavenger for proton exchange membrane fuel cells

Yttrium doped cerium oxide (CeO2·Y2O3) was studied as a free radical scavenger for PEMFCs. MEA with CeO2·Y2O3 was compared with MEAs with CeO2 and without free radical scavenger. MEAs before and after 50 h of open circuit voltage hold accelerated stress test show better performance retention with CeO2·Y2O3 than CeO2. MEAs with CeO2·Y2O3 and CeO2 perform better than the pristine MEA without free radical scavenger. ECSA, MA, and EIS of the MEAs were analyzed to confirm the effect of free radical scavengers on MEA performance and durability. XRF confirmed the improved Ce ions retention in MEAs with CeO2·Y2O3 than pure CeO2, indicating improved stability of Ce ions after doping with Yttrium. Effluents from the anode and cathode of the fuel cells were collected and analyzed by fluoride ion selective electrodes at 25 h and 50 h of the accelerated stress test. The fuel cell with CeO2·Y2O3 as a free radical scavenger has the lowest fluoride emission rate. Furthermore, the ex-situ Fenton study combined with ICP-MS analysis shows better stability of Ce in CeO2·Y2O3. This study indicates that yttrium-doped cerium oxide has better stability against dissolution and enhances the stability of polymer components against free radicals compared with CeO2, which will benefit the long-term durability of the PEMFCs.

TL, EPR, and optical properties of undoped and Eu-, Ce-, Tb-, Sm-, Cu-, Mn-, and Li- doped MgSiO3 phosphors, synthesized by sol-gel combustion technique

Polycrystalline MgSiO3 samples, undoped or doped with rare earth- (Eu, Tb, Ce, Li, Sm), transition- (Mn and Cu), and alkali metal- (Li) elements, were prepared by the sol-gel combustion method and characterized by thermoluminescence, electron spin resonance, and optical properties. Enstatite and protoenstatite phases are observed in undoped and doped MgSiO3. Better TL results have been observed for phosphors doped with Tb, Ce, and Li (0.5 % mol). Fading experiments and the GCD method have been performed. EPR signals of gamma-irradiated phosphors indicate the formation of radiation-induced defect centers. Cu-doped MgSiO3 shows an unusual feature of the Cu2+ ion. The Cu2+ ion occupies a tetragonally compressed octahedral site, presenting an unconventional attribute. Optical bandgap value Eg is higher for the Ce, Tb, Mn, Li, Sm, and Cu-doped MgSiO3 phosphors. Ce, Li, and Tb dopant ions were found suitable for the MgSiO3 sample regarding its thermoluminescent response and its possible application in radiation dosimetry.

Design and synthesis of a novel chiral photoacoustic probe and accurate imaging detection of hydrogen peroxide in vivo.

Nanocatalytic medicine, which aims to accurately target and effectively treat tumors through intratumoral in situ catalytic reactions triggered by tumor-specific environments or markers, is an emerging technology. However, the relative lack of catalytic activity of nanoenzymes in the tumor microenvironment (TME) has hampered their use in biomedical applications. Therefore, it is crucial to develop a highly sensitive probe that specifically responds to the TME or disease markers in the TME for precision diagnosis and treatment of diseases. In this work, a chiral photoacoustic (PA) nanoprobe (D/L-Ce@MoO3) based on the H2O2-catalyzed TME activation reaction was constructed in a one-step method using D-cysteine (D-Cys) or L-cysteine (L-Cys), polymolybdate, and cerium nitrate as raw materials. The designed and synthesized D/L-Ce@MoO3 chiral nanoprobe can perform in situ, non-invasive, and precise imaging of pharmacological acute liver injury. In vivo and in vitro experiments have shown that the D/L-Ce@MoO3 probe had chiral properties, the CD signal decreased upon reaction with H2O2, and the absorption and PA signals increased with increasing H2O2 concentration. This is because of the catalytic reaction between Ce ions doped in the nanoenzyme and the high expression of H2O2 caused by drug-induced liver injury to produce ·OH, which has a strong oxidizing property to kill tumor cells and destroy the Mo-S bond in the probe, thus converting the chiral probe into an achiral polyoxometalate (POM) with PA signal.

Novel self-healing glass-like CexOY film on a Flash-PEO coated AZ31B Mg alloy

The aim of this work is to develop a glass-like CexOy coating to seal the pores of a Flash-PEO coated AZ31B Mg alloy and simultaneously provide smart self-healing corrosion protection. The cerium sol was synthesized using cerium acetate as main precursor by sol-gel method. SEM micrographs revealed that upon cerium sol deposition, the pores of the oxide coating were effectively sealed, resulting in a double-layer coating system and thereby in a big reservoir of cerium ions (Ce3+/Ce4+). The glassy character of the cerium coating, confirmed by X-Ray diffraction, implies that cerium exists in Ce3+ and Ce4+ ionic states enclosed in a high internal energy structure which facilitate the diffusion of cerium ions to active cathodic zone. Electrochemical Impedance Spectroscopy (EIS), X-Ray Diffraction (XRD), and Raman spectroscopy were used to explore the active corrosion protection of the CexOy sol-gel coating. The corrosion inhibition mechanism involves the migration of cerium ions and the precipitation of insoluble-crystalline cerium compounds (CeO2). The coating demonstrated self-healing properties, presenting a promising alternative to traditional chrome conversion coatings (CCC).

Effect of Lanthanide Ions and Triazole Ligands on the Molecular Properties, Spectroscopy and Pharmacological Activity.

The effect of La, Ce, Pr and Nd ions on four Ln(ligand)3 complexes and at three DFT levels of calculation was analyzed. Four ligands were chosen, three of which were based on the 1,2,3-triazole ring. The DFT methods used were B3LYP, CAM-B3LYP and M06-2X. The relationships established were between the geometric parameters, atomic charges, HOMO-LUMO energies and other molecular properties. These comparisons and trends will facilitate the synthesis of new complexes by selecting the ligand and lanthanide ion best suited to the desired property of the complex. The experimental IR and Raman spectra of Ln(2b')3 complexes where Ln = La, Ce, Pr, Nd, Sm, Gd, Dy, Ho and Er ions have been recorded and compared to know the effect of the lanthanide ion on the complex. The hydration in these complexes was also analyzed. Additionally, the effect of the type of coordination center on the ability of an Ln(ligand)3 complex to participate in electron exchange and hydrogen transfer was investigated using two in vitro model systems-DPPH and ABTS.

Multifunctional surface modification to enhance the electrochemical performance of lithium-rich manganese-based cathode materials

The preparation of high-performance lithium-rich manganese-based cathode materials (LLOs) require attention to the redox of anions and the migration of transition metals (TM) during the cycling process. In this study, Ce ion-doped Li-rich cathode coated with La0.2Ce0.8O2, which has abundant oxygen vacancies on its surface, was prepared. The presence of the oxygen storage material La0.2Ce0.8O2 can effectively absorb the irreversible oxygen generated during cycling, preventing it from reacting with the electrolyte to form thick cathode electrolyte interface (CEI) coatings. These coatings hinder the relative activity of lattice oxygen in the bulk phase, reducing the specific capacity of the material. Additionally, the 5d metal ion Ce carries a large nuclear charge, causing a 'pinning effect' when it integrates into the LLOs structure. This effect reduces thermal oscillation in the lattice, impedes TM migration during battery charging and discharging, and effectively prevents voltage decay. Results indicate that after 100 cycles at 1C and 25 °C, the surface-coated materials maintain a discharge-specific capacity of 194 mAh/g, compared to 158 mAh/g for uncoated material. Voltage decay decreased from 4.4 mV/cycle to 1.8 mV/cycle, with an ICE of 91.5 % versus the original material's 82.8 %. The modified material also exhibits improved rate performance, retaining a specific capacity of 162 mAh/g at 3C, in contrast to the original material's 123 mAh/g.

Efficient Self-cleaning and antibacterial ceramics with active sites fully exposed obtained from rare earth waste

The utilization of rare earth polishing powder waste (RPW) to prepare antibacterial ceramics can effectively avoid problems of pollution in the recycling process and waste of rare earth resources. Herein, a novel RPW-based antibacterial ceramics was developed, which possesses the core-shell structure with ceramics as the cores and the CeO2/BiOCl as the superficial coating. The antibacterial ceramics display notable antibacterial activity, and the inactivation rates of 3.3 log under visible light irradiation in 30 min and 2.4 log under darkness in 1 h were achieved, and the zone of inhibition values was found to be 16.6 mm for E.coil. The hardness of antibacterial ceramics was measured to be 897 (±38) HV, higher than commercial porcelain's hardness (600 HV). The antibacterial mechanism was verified by the Ce ion release, reactive species, and fluorescence-based live/dead cells. This study presents a novel antibacterial ceramic structure and green economic reuse method of rare earth waste.

Enhanced energy storage properties promoted by the synergistic effects of aging effects and relaxor behavior in Ce–Mn co-doped Sr0.4Ba0.6Nb2O6 ferroelectric ceramics

In this work, Ce–Mn co-doped Sr0.4Ba0.6Nb2O6 ferroelectric ceramics were prepared by the conventional solid state reaction method. Aging effects induced by acceptor doping and relaxor behavior induced by donor doping were achieved simultaneously in Sr0.4-3x/2Ba0.6Cex(Nb0.96Mn0.04)2O6 (SBN40–4Mn-xCe) ceramics. The results show that the doping of Ce ions enters into the lattice of SBN and substitute the Sr ions, which give rise to the cell volume decreasing. The diffuseness fitting results suggest that all the co-doped samples own the relaxor characteristic. The polarization electric (P-E) loops of aged SBN40–4Mn-xCe ceramics presents constricted tendency and slimmer shape at the mean time. As a result, the Pmax-Pr values of the aged samples are higher than that of unaged samples and get an enhanced energy storage performance, which are benefited from the synergistic effects of aging effects and relaxor behavior. The composition of x = 0.04 obtained the maximum Wrec with 0.90 J/cm3 and η with 89 % after aging. Therefore, the current work may provide some guidance for improving the energy storage performance from the perspective of changing the shape of P-E loop by inducing aging behavior and relaxor behavior simultaneously.

Electrosorption-driven selective thorium removal from radioactive wastewater with phosphate – Incorporated g-C3N4 electrode

This research introduces a novel approach for developing an improved method for removing thorium ions (Th(IV)), termed as electrosorption, by fusing the principles of electricity and adsorption. The methodology involves utilizing a phosphate – incorporated graphitic carbon nitride (g-C3N4/P) electrode, synthesized via a hydrothermal – calcination process with urea as a precursor and bis (2-ethylhexyl) phosphoric acid (D2EHPA) as a dopant. Static batch experiments were conducted to explore the influence of various parameters, including voltages, initial Th(IV) concentrations and operational time, on the electrosorption of Th(IV). Characterization analysis including XRD, FT-IR, FESEM-EDS and XPS were conducted to validate the successful integration of phosphate into the g-C3N4 structure. The g-C3N4/P electrode demonstrated impressive adsorption capacity for Th(IV) electrosorption in an aqueous solution containing an initial concentration of Th(IV) at 100 mg.L−1. It was observed that applying a potential as low as −0.2 V resulted in significantly increase in the Th(IV) removal with 92.23 % (> 300 mg.g−1) within 30 minutes of duration, compared to cases without the electrochemical assistance (65.41 mg.g−1). Through FT-IR and XPS analyses, the adsorption mechanism was clarified as follows: (1) the negatively charged g-C3N4/P electrode attracted Th(IV) ions through electrostatic interaction; and (2) Th(IV) ions was coordinated with exposed oxygen (O), nitrogen (N) and phosphorus (P) atoms via complexation. In the context of real wastewater scenarios involving rare earth residue, encompassing Ce(III), La(III), Nd(III) and Pr(III) ions, the g-C3N4/P electrode showcased good capabilities in selectively adsorbing Th(IV). Additionally, the electrode synthesized in this study displayed considerable regenerative capabilities, sustaining a commendable removal ratio of approximately 70 % over five successive cycles. These findings underscore the promising potential of g-C3N4/P electrode for thorium removal through electrosorption applications.

Magnetic Switching of Second-Harmonic Generation from Single Cerium-Based Coordination Polymer Microcrystals.

Conventional access and modulation of second-harmonic generation (SHG) require precise control of crystal orientation, which faces great mechanical challenges in the case of micro/nanocrystals. Here, we demonstrate the magnetic-field-tunable SHG performance of lanthanide coordination polymer (Ce-BTC CP) microcrystals through field-aligned orientations. The coordination of Ce ions and organic ligands constructs a noncentrosymmetric structure, which not only contributes to a favorable powder SHG efficiency 3.2 times larger than that of the benchmark KH2PO4 (KDP) but also endows the microcrystals with strong magnetic anisotropy. The SHG efficiency (∼0 to 10 × KDP) depends on the orientation of the crystallographic c-axis, whereas magnetic anisotropy always aligns the c-axis with the magnetic field at a specific angle. Accordingly, the SHG can be magnetically switched by field-induced alignments. The adsorption of dyes by Ce-BTC CPs further facilitates the magnetic switching of multicolor fluorescence that can be excited by the SHG. Our work provides a new pathway for achieving SHG modulation at the microscopic level.

Autocatalytic bifunctional supramolecular hydrogels for osteoporotic bone repair.

Conventional bone scaffolds, which are mainly ascribed to highly active osteoclasts and an inflammatory microenvironment with high levels of reactive oxygen species and pro-inflammatory factors, barely satisfy osteoporotic defect repair. Herein, multifunctional self-assembled supramolecular fiber hydrogels (Ce-Aln gel) consisting of alendronate (Aln) and cerium (Ce) ions were constructed for osteoporotic bone defect repair. Based on the reversible interaction and polyvalent cerium ions, the Ce-Aln gel, which was mainly composed of ionic coordination and hydrogen bonds, displayed good injectability and autocatalytic amplification of the antioxidant effect. In vitro studies showed that the Ce-Aln gel effectively maintained the biological function of osteoblasts by regulating redox homeostasis and improved the inflammatory microenvironment to enhance the inhibitory effect on osteoclasts. Ribonucleic acid (RNA) sequencing further revealed significant downregulation of various metabolic pathways, including apoptosis signaling, hypoxia metabolism and tumor necrosis factor-alpha (TNF-α) signaling via the nuclear factor kappa-B pathway after treatment with the Ce-Aln gel. In vivo experiments showed that the clinical drug-based Ce-Aln gel effectively promoted the tissue repair of osteoporotic bone defects by improving inflammation and inhibiting osteoclast formation at the defect. Notably, in vivo systemic osteoporosis was significantly ameliorated, highlighting the strong potential of clinical translation for precise therapy of bone defects.

Synthesis and study of the sorption potential of hydrotalcite modified biochars (LDH@BC) with respect to cerium(III) ions

The innovative LDH@BC composites containing combination of metals: Zn/Al, Co/Al, Mg/Al, Ca/Al at the molar ratio 3/1 were synthesized using the co-precipitation method at constant pH. The composites were applied to remove Ce(III) ions from aqueous solutions. Batch experiments were conducted for determination of influence of solution pH, phase contact time, solution concentration and temperature. The kinetic and isotherm parameters were found using the non-linear regression method. As follows from the thermodynamic tests LDH@BC are more effective removal of Ce(III) ions at higher temperature and the sorption process is unforced and spontaneous. The leaching studies proved that 1 mol/L nitric acid is the best desorbing agent for Ce(III) ions deposited on the sorbent surface. Additionally, the composites were investigated applying the XRD and BET analyses (before sorption) as well as the ATR-FTIR, SEM-EDX, XPS methods (before and after the Ce(III) ions sorption). In summary, the introduction of hydrotalcite composed of Zn/Al, Co/Al, Mg/Al, Ca/Al as modifiers of biochar surface produced a potentially more cost-effective, and non-toxic cerium adsorbent for waters and wastewaters treatment.

Effect of Ce-doping on the structural, optical and photoluminescence characteristics of nano Zn0.75Cd0.25S

Nano Zn0.75CexCd0.25S samples with different doping amounts of cerium (x = 0.0, 0.02, 0.04, 0.06) were synthesized using the thermolysis approach. The possibility of Ce ion incorporation into the ZnS0.75Cd0.25S lattice either substitutionally for Zn/Cd or interstitially into the voids of the lattice was examined using Rietveld refinement analysis based on X-ray diffraction (XRD) data. The lattice parameters, crystallite size and microstrain of the formed samples were computed. Particles with homogeneous spherical morphology can be seen using TEM technique with nano size of 2–4 nm, approving the values obtained from XRD. The optical properties of the prepared samples were examined by the diffuse reflectance spectroscopy technique. The optical energy gap value of Zn0.75Cd0.25S is 2.79 eV. As the Ce content rose, this value decreased until it reached 2.68 eV. The refractive index (n) values derived from numerous models, along with the average n values for all samples were calculated. The incorporation of Ce doping into nano Zn0.75-xCexCd0.25S samples results in an increase in their dielectric constants, suggesting their potential role for energy storage applications. With a rise in Ce doping, the non-linear optical parameters of Zn0.75-xCexCd0.25S were improved. Gaussian function fitting was used to decompose the photoluminescence (PL) emission of different samples. Upon doping with Ce, a noticeable reduction in the PL intensity was observed. The sample without any doping showed a cyan color, whereas the doped samples exhibited a cyan-green color.

Oxygen vacancy and Ce ion co-synergize to enhance the photocatalytic degradation performance of FeTiO3: An experimental and DFT study

Doping the iron titanate (FeTiO3) with rare earth element is considered as an effective method of enhancing its photocatalytic performance. In this work, the novel FeTiO3 doped with cerium (Ce) (Ce/FeTiO3) photocatalysts were designed and synthesized using the sol–gel method. The 10 mol% Ce/FeTiO3 photocatalyst displays excellent photocatalytic performance for degrading the tetracycline hydrochloride (TCH), methylene blue (MB) and brilliant blue (BB). The degradation efficiencies are 97.50 % (TCH), 95.40 % (MB), and 84.60 % (BB), respectively, and the degradation rate constants (k) are 3.68, 2.91, and 7.12 times that of pure FeTiO3. Density functional theory (DFT) calculations were used to study the photocatalytic degradation mechanism in depth. The results show that the content of oxygen vacancy is increased and the oxygen vacancy formation energy is significantly increased from 2.25 eV to 6.97 eV after doping the Ce ion, which can provide more active sites to degrade pollutants and enhance the photocatalytic performance of the FeTiO3. Furthermore, the Ce 4f orbital can narrow the bandgap and form the impurity level to capture the photoexcited electron, inhibiting the recombination rate of photocarriers in FeTiO3. This work is expected to provide a valuable insight into the Ce doped FeTiO3 photocatalyst, which is conductive to expanding the practical applications of FeTiO3-based photocatalyst.

Introducing Ce ions and oxygen vacancies into VO2 nanostructures with high specific surface area for efficient aqueous Zn-ion storage

Positive electrodes play a decisive role in exploring the Zn2+ storage mechanism and improving the electrochemical performance of aqueous Zn-ion batteries (AZIBs). Feasible design and preparation of cathode materials have been crucial for AZIBs in recent years. Herein, taking the advantage of the tunnel structure of VO2, which can withstand volume change during charging/discharging, VO2 doped with Ce ions is synthesized by a simple one-step hydrothermal method and oxygen vacancies are synchronously generated during synthesis. It delivers a capacity of 158.5 mAh g−1 at the current density of 5 A g−1 after 1000 cycles and exhibits an excellent energy density of 312.8 Wh kg−1 at the power density of 142 W kg−1. The structural modification and prospect of enhancing its conductivity by doping with rare-earth metals and introducing oxygen vacancies may aid in improving the stability of AZIBs in the future.

Anti-inflammatory cerium-containing nano-scaled mesoporous bioactive glass for promoting regenerative capability of dental pulp cells.

This study aimed to investigate the anti-inflammatory and odontoblastic effects of cerium-containing mesoporous bioactive glass nanoparticles (Ce-MBGNs) on dental pulp cells as novel pulp-capping agents. Ce-MBGNs were synthesized using a post-impregnation strategy based on the antioxidant properties of Ce ions and proposed the first use of Ce-MBGNs for pulp-capping application. The biocompatibility of Ce-MBGNs was analysed using the CCK-8 assay and apoptosis detection. Additionally, the reactive oxygen species (ROS) scavenging ability of Ce-MBGNs was measured using the 2,7-Dichlorofuorescin Diacetate (DCFH-DA) probe. The anti-inflammatory effect of Ce-MBGNs on THP-1 cells was further investigated using flow cytometry and quantitative real-time polymerase chain reaction (RT-qPCR). Moreover, the effect of Ce-MBGNs on the odontoblastic differentiation of the dental pulp cells (DPCs) was assessed by combined scratch assays, RT-qPCR, western blotting, immunocytochemistry, Alizarin Red S staining and tissue-nonspecific alkaline phosphatase staining. Analytically, the secretions of tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were detected with enzyme-linked immunosorbent assay (ELISA). Ce-MBGNs were confirmed to effectively scavenge ROS in THP-1-derived macrophages and DPCs. Flow cytometry and RT-qPCR assays revealed that Ce-MBGNs significantly inhibited the M1 polarization of macrophages (Mφ). Furthermore, the protein levels of TNF-α and IL-1β were downregulated in THP-1-derived macrophages after stimulation with Ce-MBGNs. With a step-forward virtue of promoting the odontoblastic differentiation of DPCs, we further confirmed that Ce-MBGNs could regulate the formation of a conductive immune microenvironment with respect to tissue repair in DPCs, which was mediated by macrophages. Ce-MBGNs protected cells from self-produced oxidative damage and exhibited excellent immunomodulatory and odontoblastic differentiation effects on DPCs. As a pulp-capping agent, this novel biomaterial can exert anti-inflammatory effects and promote restorative dentine regeneration in clinical treatment. We believe that this study will stimulate further correlative research on the development of advanced pulp-capping agents.

Customizing Cerium Oxide Particle Synthesis with Hybrid Polyion Complex Templates for Enhanced Oxidation Performance in Photo-Fenton Processes.

Hybrid poly-ion complexes were synthesized through the complexation of a double hydrophilic copolymer with Ce(III) ions. These colloids act as reservoirs for cerium ions, enabling the synthesis of cerium-based Prussian blue nanoparticles with a cubic structure, a narrow size distribution around 100 nm, and good colloidal stability in water. Upon high-temperature calcination, these nanoparticles are transformed into a cerium/iron-based metal oxide catalyst (CeO2/Fe2O3). The resultant composite catalyst demonstrates superior performance in the photo-Fenton oxidation of methylene blue pollutants, achieving a conversion efficiency that rivals other metal-based oxides and cerium-based catalysts.