Abstract: Regulating appropriate valence states of metal active centers, such as Ce3+/Ce4+ and Mn3+/Mn2+, as well as surface vacancy defects, is crucial for enhancing the catalytic activity of cerium‐based and manganese‐based nanozymes. Drawing inspiration from the efficient substance exchange in rhizobia‐colonized root cells of legumes, we developed a symbiosis nanozyme system with rhizobia‐like nano CeOx clusters robustly anchored onto root‐like Mn3O4 nanosupports (CeOx/Mn3O4). The process of "substance exchange" between Ce and Mn atoms—reminiscent of electron transfer—not only fine‐tunes the metal active sites to achieve optimal Ce3+/Ce4+ and Mn3+/Mn2+ ratios but also enhances the vacancy ratio through interface defect engineering. Additionally, the confinement anchoring of CeOx on Mn3O4 ensures efficient electron transfer in catalytic reactions. The final CeOx/Mn3O4 nanozyme demonstrates potent catalase‐like (CAT‐ like) and superoxide dismutase‐like (SOD‐like) activities, excelling in both chemical settings and cellular environments with high reactive oxygen species (ROS) levels. This research not only unveils a novel material adept at effectively eliminating ROS but also presents an innovative approach for amplifying nanozyme efficacy.

Abstract: Abstract δ‐MnO 2 has been vigorously developed as an ideal cathode material for rechargeable aqueous zinc‐ion batteries (AZIBs) due to its spacious layer spacing suitable for ion storage. However, poor intrinsic conductivity, structural collapse, and sluggish reaction kinetics are major limitations restricting their battery performance. Doping engineering has been proven to be an effective strategy for modifying the structure, conductivity, and electronic properties of Mn‐based oxides. Here, a series of δ‐MnO 2 hierarchical flowers with different cerium‐doped sites are proposed as high‐performance cathodes for AZIBs, revealing the effects of various Ce doping sites on the MnO 2 layer‐by‐layer structure and battery performance. Chemical analysis and theoretical calculations indicate that δ‐MnO 2 with both in‐layer and interlayer Ce doping (Ce in/inter ‐MnO 2 ) allows for sufficient Zn 2+ storage sites, higher conductivity, and enhanced reaction kinetics due to enlarged interlayer spacing, increased oxygen defects, and reduced Coulombic repulsion between zinc ions and manganese oxide hosts. As a result, Ce in/inter ‐MnO 2 with extended ion transfer channels and sturdy structure delivers a superior capacity of 348.8 mAh g −1 at a current density of 300 mA g −1 over 100 cycles, and a high retention rate of ≈100% at a current density of 3000 mA g −1 over 2000 cycles.

Abstract: Phosphate removal plays a pivotal role in alleviating eutrophication and maintaining water quality. Cerium (Ce) demonstrates considerable promise in phosphate removal, attributed to its strong affinity for phosphate ions. This study provides a dual utilization strategy for synthesizing Fe2O3- and CeCO3OH-decorated hydrophilic porous biochar (Fe/Ce@HPBC), designed for phosphate recovery from eutrophic waters and followed by its application as a slow-release phosphate fertilizer. Fe/Ce@HPBC possessed excellent phosphate adsorption quantity, achieving a maximum uptake of 203.88 mg/g in accordance with the Sips model. Furthermore, the slow-release experiment demonstrated that Fe/Ce@HPBC used as a fertilizer after phosphate recovery could sustainably release 39.8% of its phosphate content within 28 days. Fe/Ce@HPBC-P could also significantly increase the effective phosphorus content of soil by 65.51% and promote the phosphorus uptake of maize seedlings by 70.36%. Mechanistic investigation revealed that the outstanding phosphate adsorption by Fe/Ce@HPBC was attributed to the formation of inner-sphere complexation through ligand exchange between phosphate and Ce(HCO3)2+/Ce–OH, in addition to electrostatic attraction caused by enhanced surface protonation. Overall, this study contributes to the advancement of phosphate recovery techniques and promotes the development of sustainable agriculture by presenting an effective strategy for mitigating eutrophication.

Abstract: Nanostructured CeO2 was fabricated through a facile sonochemical route utilizing cerium (III) nitrate hexahydrate as a metal source and mentha extract as a novel capping agent. To our knowledge, this experimental work is the first successful endeavor for fabricating nanostructured CeO2 employing mentha extract by an easy and eco-friendly route. The microstructure and various characteristics of the oxide nanostructure prepared utilizing mentha extract were investigated using various methods. This research examined the anticancer effects of green synthesized cerium oxide nanoparticles (CeO2-NPs) on cancer cell lines (T98 and SHSY5Y) at several concentrations of 0.0, 0.05, 0.1, 0.2, 0.4, and 0.8 mg/ml NPs by exposure time of 24/48 h. The obtained results presented a cytotoxicity of the prepared NPs against the cancerous cell lines. Considering the CeO2-NP's effects on cancer cells indicated significant toxicity against cancer cell lines, these nanoparticles could be applied in medicine and in developing new drug formulations for cancer cell lines. Additional investigations are desired to reveal other biological applications of synthesized NPs against normal and other cancerous cell lines.

Abstract: Rare-earth ion dopants in solid-state hosts are ideal candidates for quantum communication technologies, such as quantum memories, due to the intrinsic spin–photon interface of the rare-earth ion combined with the integration methods available in the solid state. Erbium-doped cerium oxide (Er:CeO2) is a particularly promising host material platform for such a quantum memory, as it combines the telecom-wavelength (∼1.5μm) 4f–4f transition of erbium, a predicted long electron spin coherence time when embedded in CeO2, and a small lattice mismatch with silicon. In this work, we report on the epitaxial growth of Er:CeO2 thin films on silicon using molecular beam epitaxy, with controlled erbium concentration between 2 and 130 parts per million (ppm). We carry out a detailed microstructural study to verify the CeO2 host structure and characterize the spin and optical properties of the embedded Er3+ ions as a function of doping density. In as-grown Er:CeO2 in the 2–3 ppm regime, we identify an EPR linewidth of 245(1) MHz, an optical inhomogeneous linewidth of 9.5(2) GHz, an optical excited state lifetime of 3.5(1) ms, and a spectral diffusion-limited homogeneous linewidth as narrow as 4.8(3) MHz. We test the annealing of Er:CeO2 films up to 900 °C, which yields narrowing of the inhomogeneous linewidth by 20% and extension of the excited state lifetime by 40%.

Abstract: Reactive oxygen species (ROS) play crucial roles in the pathogenesis of inflammatory bowel disease (IBD) by disrupting the mucosal barrier and subsequently leading to the dysregulation of the gut microbiome. Therefore, ROS scavengers present a promising and comprehensive strategy for the effective IBD treatment. In the current work, we explored the therapeutic potential of cerium dioxide (CeO

Abstract: This study presents a facial and quick electrochemical sensor platform that offers remarkable water and food safety applications. The present work represents a study of the synthesis and characterization for efficient cerium vanadate (CeVO

Abstract: Progressing the anti-corrosion performance of thin-film coatings has always been the focus of researchers. In this research, a novel high-resistance inorganic coating against corrosion was developed. For this aim, the steel plates treated with the Mn ion-containing zinc phosphate conversion coating were prepared and then covered with a layer of crystalline MOF nanoparticles. A robust self-healing effect was provided by the cerium cations loaded into the MOF thin coating, pores. FE-SEM, BET, XRD, and XPS were applied as the main analyses to characterize the successful formation of the conversion coating and the MOF grown on its layer. The uniformly grown MOF single crystals (particle size: 200–300 nm) could cover the porosities of the zinc phosphate coating so that no rust was detected after 600 h of keeping the sample in a very aggressive environment (salt spray chamber). Also; based on PDP results, the modified coating (ZPMnMOFCe) showed a sixty-fold drop in the corrosion rate compared to the uncoated plate. Meantime; after 24 h of exposure, its log|Z|10mHz was two orders of magnitude higher than that for the untreated mild steel.

Abstract: Superhydrophobic conversion coatings have attracted increasing attention in corrosion protection field due to their exceptional water-repellent properties. However, the retention of protective properties with surface wettability dynamics remains a significant challenge. Herein, a superhydrophobic coupling cerium coating with hierarchical structure is fabricated via cerium-doped deep eutectic solvent pretreatment and modification to extend corrosion resistance duration. The synergistic enhancement between hydrophobicity and active protection can significantly improve the anti-corrosion characteristics of magnesium alloys, resulting in a decrease in corrosion current density by an order of magnitude. The superhydrophobic surface can prevent the metal from corrosive media by reducing the contact area and thus slow down the corrosion rate. The cerium compound within the coating can form a cerium protective layer during the corrosion reaction of magnesium alloy, inhibiting the further corrosion process. Furthermore, the density functional theory (DFT) calculation revealed the corrosion protection mechanism of superhydrophobic coatings. Combining experimental investigations with theoretical calculations, this work provides a new strategy for enhanced anti-corrosion protection of superhydrophobic coatings.

Abstract: Modern era demands development of hybrid supercapacitor amalgamating characteristics of battery and supercapacitor is a single unit. Various contender electrode materials have been used so far, however, metal organic frameworks, having rich porosity and distinctive electrochemical properties can be integrated in energy storage devices to improve electrochemical performance. Herein, we have synthesized Ce-PTA-MOF from pyridine-2,4,6-tricarboxylic acid which was structurally as well as electrochemically characterized. Effects of different concentrations of KOH electrolyte on electrochemical properties of Ce-PTA-MOF electrode has been investigated using three electrodes assembly and practical applications of hybrid supercapacitor device has also been explored by fabricating it with activated carbon. The stability and capacitive-diffusive contributions of the hybrid supercapacitor has been analyzed by theoretical approach. The specific capacity, maximum energy density and power density were calculated as 115 C/g, 26.75 Wh/kg and 5760 W/kg respectively which showed efficiency of 99.2 % even after 5000 GCD cycles. High energy density and power density with extraordinary stability make Ce-PTA-MOF electrode a promising candidate for futuristic hybrid supercapacitor devices.

Abstract: The present work reports an improvement in the photocatalytic performance of cerium ferrite (CeFeO3) via doping of antimony (Sb) towards the photodegradation of toxic pharmaceutical pollutant i.e. diclofenac potassium. The variable concentrations of Ce1-xSbxFeO3 (x = 0.00, 0.01, 0.03, 0.05, 0.06, 0.07, 0.09) were prepared using facile co-precipitation route and subsequently characterized for their optical, structural, morphological, and dielectric properties using various analytical techniques. It was established that an increase in Sb concentration as dopant (up to x = 0.07) reduced the optical band gap from 2.74 eV to 2.42 eV making it suitable candidate for photodegradation. The X-ray diffraction (XRD) pattern revealed orthorhombic phase of synthesized materials with small crystallite sizes in the range of 15.28 to 2.42 nm. The high value of dielectric constant (3.5841 × 106) for Ce0.93Sb0.07FeO3 with small loss tan (3.1208) compared with the CeFeO3 indicated its ability as photocatalyst to effectively store charges to make them utilize for photocatalytic activity. The degradation efficiency of Ce0.93Sb0.07FeO3 reached 86.7% in 120 min of light irradiation under optimized conditions (pH = 4, catalyst dosage = 15 mg, primary drug concentration = 5 mg/L). Ce0.93Sb0.07FeO3 was also found to be stable over its multiple catalytic runs as only 6.5% decline in degradation efficiency was observed in recyclability test. The remarkable performance of antimony doped cerium ferrite against the removal of persistent pharmaceutical pollutant indicated its strong potential to be used in wastewater treatment in future works.

Abstract: The extraction of lanthanides in spent fuel reprocessing plays a key role in the development of nuclear energy. In this work, the extraction of the typical fissionable cerium elements has been studied by electrolytic co-reduction of Al(III) and Ce(III) in LiCl-KCl-CeCl3 molten salts assisted by KAlCl4. The electrochemical behavior of the reduction of Al(Ⅲ) and Ce(Ⅲ) on a molybdenum electrode was studied by cyclic voltammetry (CV), square wave voltammetry (SWV), and open circuit chronopotentiometry (OCP), and specific peaks of five Al-Ce intermetallic compounds were detected. After 2.7 h of galvanostatic electrolysis at a current density of 0.064 A cm−2, the extraction efficiency and current efficiency of Ce(Ⅲ) reached 99.9 % and 91.3 % respectively. Potentiostatic electrolysis is slightly more efficient, with 99.9 % Ce(Ⅲ) extraction in 3.5 h at a current efficiency of 97.8 %. The products of electrolysis are rod-shaped alloys (Al11Ce3, Al3Ce, Al2Ce), and the molten salts purified by electrolytic separation are free of impurity signals and can be reused for electrolytic refining.

Abstract: Hydrogen gas has been considered an eco-friendly energy source with a high energy content, making it a suitable energy carrier for several industries. A cerium-organic framework, denoted as CeOF, was synthesized by reacting cerium with a tricarboxylic organic linker using a solvothermal method. The material's characteristics were analyzed using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transforms infrared spectroscopy (FT-IR) to confirm its crystallinity, phase purity, elemental composition, chemical bonding, morphology, and thermal stability. CeOF catalysized the release of hydrogen from solid hydrogen storage materials, e.g., sodium borohydride (NaBH4) by the reaction with water via hydrolysis. An examination was carried out to analyze the influence of catalyst loading, NaBH4 weight (0.2–3 wt.%), and reaction temperature. The CeOF catalyst showed a significant hydrogen generation rate (HGR) of 1800 mLH2·gcat-1·min−1, with an activation energy of 58.8 kJ·mol−1. It showed good catalytic recyclability enabling continuous hydrogen production for four cycles without any significant decrease in the material's performance.

Abstract: Acute lung injury (ALI) is a life threatening disease in critically ill patients, and characterized by excessive reactive oxygen species (ROS) and inflammatory factors levels in the lung. Multiple evidences suggest that nanozyme with diversified catalytic capabilities plays a vital role in this fatal lung injury. At present, we developed a novel class of polydopamine (PDA) coated cerium dioxide (CeO

Abstract: The real-time monitoring of volatile sulfur compounds is indispensable; however, it continues to pose a significant challenge due to issues such as limited performance towards parts-per-billion (ppb)-level gas. Herein, a concept of synergistic sensitization effects involving single-atom gold (Au) and cerium (Ce) dopants is proposed to boost the sensing performance of allyl mercaptan, a common volatile sulfur compound. As a proof-of-concept, a chemiresistive gas sensor based on mesoporous SnO

Abstract: Excessive production of reactive oxygen species (ROS) around titanium implants under diabetic conditions causes persistent inflammation, leading to poor osseointegration and even implant failure. Surface modification is an effective way to promote ROS clearance, alleviate inflammation, and stimulate bone formation. In this study, a multifunctional coating is fabricated by introducing cerium (Ce)-containing mesoporous bioactive glass nanoparticles (Ce-MBGNs) onto the titanium surface via an electrophoretic deposition method. The incorporation of Ce-MBGNs remarkably improves surface hydrophilicity by increasing the surface areas. The bioactive ions are appropriately released, thereby promoting mesenchymal stem cell proliferation and differentiation under diabetic conditions. The conversion between Ce(III) and Ce(IV) endows Ce-MBGNs coating with antioxidative nanoenzymes properties to scavenge diabetes-induced ROS, resulting in macrophage polarization towards the anti-inflammatory phenotype. The therapeutic effect of Ce-MBGNs-modified titanium implants is also verified in diabetic rats by inhibiting inflammatory responses and accelerating early osseointegration. Taken together, the findings reveal that the ROS-scavenging and immunomodulation activity of the Ce-MBGNs coating contributes to enhanced osseointegration, and provides a novel implant surface for diabetic patients.

Abstract: Cerium-based adsorbents possessed unique advantages of valence variability and abundant oxygen vacancies in hexavalent chromium (Cr(VI)) adsorption, but high cost and unstable properties restricted their application in Cr(VI) contained wastewater treatment. Herein, a series of bimetallic adsorbents with different cerium/iron ratios (CeFe@C) were prepared by adding inexpensive Fe into Ce-based adsorbents (Ce@C), and the effect of Fe doping on adsorption properties of Ce@C for Cr(VI) was investigated thoroughly. Compared with pristine Ce@C, CeFe@C exhibited excellent removal performance for Cr(VI), and the improved maximum adsorption capacity reached 75.11 mg/g at 25℃. Benefiting from Fe doping, CeFe@C had good regeneration property, with only 25 % decrease after five adsorption–desorption cycles. Contents of trivalent cerium (Ce(III)) and oxygen vacancies (Ov) in bimetallic adsorbents were positively correlated with divalent iron (Fe(II)) doping, indicating that the formation of Ce(III) and surface defects on Ce@C could be effectively regulated by Fe doping. Density functional theory (DFT) calculation results further proved that the doped Fe enhanced the electron transfer effectively and lowered the energy barriers of Cr(VI) adsorption onto Ce@C surface, strengthening the reduction and complexation to Cr(VI). This study provides new insights for improving the Cr(VI) removal performance by modified Ce-based adsorbents, and further promotes the utilization potentiality of low-cost and low-toxicity Ce-based adsorbents in Cr(VI)-containing wastewater treatment.

Abstract: Bone, an actively metabolic organ, undergoes constant remodeling throughout life. Disturbances in the bone microenvironment can be responsible for pathologically bone diseases such as periodontitis, osteoarthritis, rheumatoid arthritis and osteoporosis. Conventional bone tissue biomaterials are not adequately adapted to complex bone microenvironment. Therefore, there is an urgent clinical need to find an effective strategy to improve the status quo. In recent years, nanotechnology has caused a revolution in biomedicine. Cerium(III, IV) oxide, as an important member of metal oxide nanomaterials, has dual redox properties through reversible binding with oxygen atoms, which continuously cycle between Ce(III) and Ce(IV). Due to its special physicochemical properties, cerium(III, IV) oxide has received widespread attention as a versatile nanomaterial, especially in bone diseases. This review describes the characteristics of bone microenvironment. The enzyme-like properties and biosafety of cerium(III, IV) oxide are also emphasized. Meanwhile, we summarizes controllable synthesis of cerium(III, IV) oxide with different nanostructural morphologies. Following resolution of synthetic principles of cerium(III, IV) oxide, a variety of tailored cerium-based biomaterials have been widely developed, including bioactive glasses, scaffolds, nanomembranes, coatings, and nanocomposites. Furthermore, we highlight the latest advances in cerium-based biomaterials for inflammatory and metabolic bone diseases and bone-related tumors. Tailored cerium-based biomaterials have already demonstrated their value in disease prevention, diagnosis (imaging and biosensors) and treatment. Therefore, it is important to assist in bone disease management by clarifying tailored properties of cerium(III, IV) oxide in order to promote the use of cerium-based biomaterials in the future clinical setting. In this review, we focused on the promising of cerium-based biomaterials for bone diseases. We reviewed the key role of bone microenvironment in bone diseases and the main biological activities of cerium(III, IV) oxide. By setting different synthesis conditions, cerium(III, IV) oxide nanostructures with different morphologies can be controlled. Meanwhile, tailored cerium-based biomaterials can serve as a versatile toolbox (e.g., bioactive glasses, scaffolds, nanofibrous membranes, coatings, and nanocomposites). Then, the latest research advances based on cerium-based biomaterials for the treatment of bone diseases were also highlighted. Most importantly, we analyzed the perspectives and challenges of cerium-based biomaterials. In future perspectives, this insight has given rise to a cascade of cerium-based biomaterial strategies, including disease prevention, diagnosis (imaging and biosensors) and treatment.

Abstract: Catalytic methane decomposition is an economical and green procedure to procreate COx-free hydrogen as a renewable energy source. This paper describes the mesoporous high surface area Ni/Al2O3 catalysts enhanced with the rare earth metals (cerium, lanthanum, and yttrium) fabricated via neoteric one-pot hydrothermal strategy, and the co-catalysts performance in the methane decomposition process, explores. This comparative study shows that Yttria exhibited dramatic catalytic activity and thermal stability among the above promoters. The maximum CH4 conversions of 61.16, 68.61, and 63.74 % have been obtained over the 50Ni-xY/Al2O3 (x = 2.5, 5, and 10 wt%) at 650 °C and GHSV = 24000 mL.(h.gcat)−1, respectively. The optimal sample (5 wt% Y-doped) reveals a superior lifetime in high-temperature stability tests after 10 h. Moreover, the analysis of carbon nanofiber's textural properties indicates that Y loading leads to highly graphitized (ID/IG = 1.22 to 0.98) and the formation of a carbon lattice with supreme crystallization.

Abstract: Cobalt-cerium bimetallic oxides (CoCeOx) with rich oxygen vacancies (OVs) were prepared by solvothermal method for peroxymonosulfate (PMS) activation efficiently, and the effect of OVs on reactive species formation was discussed. Carbamazepine (CBZ), a widely used anti-epileptic drug, also a typical pharmaceutical and personal care products (PPCPs) in the water environment, could be removed by 98 % in 40 min with low addition of CoCeOx and PMS in the CoCeOx/PMS system. Through a series of quenching experiments and electron paramagnetic resonance, it was confirmed that the main reactive species for decontamination were high-valent cobalt oxygen species (Co(IV)). Through the OVs detection and the contribution calculation of radicals and non-radicals on CBZ removal, it was found that OVs promoted the transformation from radicals to non-radicals (mainly Co(IV)) in the systems. In addition, cerium doping played an important role in promoting Co (II) / Co (III) cycle and OVs regeneration. Density functional theory (DFT) calculation revealed the formation process of Co(IV), and further proved that OVs could promote the formation of Co(IV). Evaluated by quantitative structure–activity relationship (QSAR) analysis, the ecotoxicity of CBZ and its main intermediates was significantly decreased. Overall, this study deepens the understanding of OVs promoting the formation of high-valent metal oxygen species (HVMO), as well as provides feasibility for the removal of refractory organics in wastewater.

Abstract: Mechanism of cerium-based inclusion formation and influence on impact toughness were researched in industrial Al-killed steel. In the final product, actual inclusions were complex, consisting of Al-O-Ce (Ce-poor), Al-O-Ce (Ce-rich), Al-O-Ce-S(Al-poor) and S-Ca (Mn-rich) from inside to outside. Results of thermodynamic balance calculation were completely inconsistent with the actual inclusions. Considering decomposing or disappearing of formed inclusions in steel difficult, new computing results showed that inclusions were formed by firstly Al 2 O 3 (exist in molten steel before adding Ce), AlCeO 3 , Ce 2 O 2 S, CaS, Ca (Mn)S and MnS in turn, in better agreement with the actual inclusions. Outside of the actual inclusions, Ce 2 O 2 S and CaS had a smaller disregistry with ferrite, which could offer effective nucleation sites. And small inclusion was surrounded in a grain and bigger inclusion was surrounded in two grains at least. Microstructures were observed that grains with Ce were finer than grains without Ce. Moreover, V-notch impact toughness of samples was tested at 0 and −60°C, respectively. Compared with samples without Ce, the values of impact toughness were increased by 161% at 0°C and 225% at −60°C, respectively. And fracture surface with Ce had more and finer dimples and finer cleavages than that without Ce.

Abstract: This perspective demonstrates the green synthesis of CeO 2 -NPs with Oroxylum indicum fruit extract.