Influence Of Rare Earth Elements Research Articles

Effect of Rare Earth Elements on Microstructure and Tensile Behavior of Nb-Containing Microalloyed Steels.

The present investigation endeavors to explore the influence of rare earth elements on the strength and plasticity characteristics of low-carbon microalloyed steel under tensile loading conditions. The findings from the conducted tensile tests indicate that the incorporation of rare earths leads to a notable enhancement in the yield strength, ultimate tensile strength, and ductility properties of the steel. A comparative analysis of the microstructures reveals that the presence of rare earths significantly refines and optimizes the microstructure of the microalloyed steel. This optimization is manifested through a reduction in grain size, diminution of inclusion sizes, and a concomitant rise in their number density. Moreover, the addition of rare earths is observed to foster an increase in the volumetric fraction of carbides within the steel matrix. These multifaceted microstructural alterations collectively contribute to a substantial strengthening of the microalloyed steel. Furthermore, it is elucidated that the synergistic interaction between rare earth elements and both carbon (C) and niobium (Nb) in the steel matrix augments the extent of the Lüders strain region during the tensile deformation of specimens. This phenomenon is accompanied by the effective modification of inclusions by the rare earths, which serves to mitigate stress concentrations at the interfaces between the inclusions and the surrounding matrix. This article systematically evaluates the modification mechanism of rare earth microalloying, which provides a basis for broadening the application of rare earth microalloying in microalloyed steel.

Magnetoelastic Coupling Evidence by Anisotropic Crossed Thermal Expansion in Magnetocaloric RSrCoFeO6 (R = Sm, Eu) Double Perovskites.

Double perovskite oxides, characterized by their tunable magnetic properties and robust interconnection between the lattice and magnetic degrees of freedom, present an enticing foundation for advanced magnetic refrigeration materials. Herein, we delve into the influence of rare-earth elements on RSrCoFeO6 (R = Sm, Eu) disordered double perovskites by examining their structural, electronic, magnetic, and magnetocaloric properties. Temperature-dependent synchrotron X-ray diffraction analysis confirmed the stability of the orthorhombic phase (Pnma) across a wide temperature range. X-ray photoemission spectroscopy revealed that both Sm and Eu are in the 3+ state, whereas multiple states for Co2+/3+ and Fe3+/4+ are identified. The magnetic investigation and magnetocaloric effect (MCE) analysis brought to light the presence of a long-range antiferromagnetic (AFM) order with a second-order phase transition (SOPT) in both samples. The maximum magnetic entropy change ΔSMmax was approximately 0.9 J/kg K for both samples at applied field 0-7 T, manifesting prominently above Neel temperatures TN ≈ 93 K (Sm) and 84 K (Eu). Nevertheless, different relative cooling powers (RCP) of 112.6 J/kg (Sm) and 95.5 J/kg (Eu) were observed. A detailed analysis of the temperature-dependent lattice parameters shed light on a distinct magnetocaloric effect across the magnetic transition temperature, unveiling an anisotropic thermal expansion [αV = 1.41 × 10-5 K-1 (Sm) and αV = 1.54 × 10-5 K-1 (Eu)] wherein the thermal expansion axial ratio αbSm/αbEu = 0.61 became lower with increasing temperature, which suggests that the Eu sample experiences a greater thermal expansion in the b-axis direction. At the atomic bonding level, the evidence for magnetoelastic coupling around the magnetic transition temperatures TN was found through the anomalies along the average Co/Fe-O bond distance, formal valence, octahedral distortion, as well as an anisotropic lattice expansion.

Corrosion mechanisms of high-entropy rare earth zirconate (Gd0.2Y0.2Er0.2Tm0.2Yb0.2)2Zr2O7 exposed to CMAS and multi-medium (NaVO3+CMAS)

The wettability and thermal corrosion behavior of CMAS and CN (CMAS+NaVO3) on high-entropy rare-earth zirconate (Gd0.2Y0.2Er0.2Tm0.2Yb0.2)2Zr2O7 (HEZ) at high temperature were studied and compared. The results reveal that HEZ is a promising TBCs material with good anti-CMAS performance. However, HEZ exhibits poor resistance to CN, and the reaction layer fails to effectively alleviate the melt penetration. Based on the calculation of OB (optical basicity) theory, the possibility that NaVO3 can improve the reaction activity of CMAS is ruled out. It was determined that NaVO3 depolymerizes the internal network structure of the CMAS, resulting in a lower melting point and viscosity, stronger wettability, and permeability of CN compared to CMAS, thus posing greater harmfulness. The influence of rare earth elements with different ionic radii on the formation of multicomponent RE-crystal was researched by crystal structure analysis and first-principles calculation, providing a theoretical basis for the reliability of the corrosion mechanism.

Influence of rare-earth elements (RE = Ce, Nd, Gd) on structural, ESR and Mössbauer spectroscopy studies of Ni0.5Co0.5RE0.03Fe1.97O4 synthesized by glycol-thermal method

Nanocrystalline Ni0.5Co0.5RE0.03Fe1.97O4 (RE = Ce, Nd, Gd) were synthesized by glycol-thermal method. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results confirm the formation of single-phase spinel ferrite. The crystallite sizes ranged from 6.29 nm to 9.41 nm which was comparable to results obtained using Williamson-Hall (W–H) method. Lattice parameters were found to vary from 8.356 Å to 8.370 Å depending on an ionic radii of a substituted rare-earth elements. Large specific surface areas ranging between 120 m2/g and 160 m2/g were associated with smaller crystallite sizes. Scanning electron microscope (SEM) revealed homogeneous and clustered nanoparticles. The energy dispersive X-ray (EDS) spectra revealed the existence of nickel (Ni), cobalt (Co), iron (Fe), and oxygen (O) in an undoped sample. The additional characteristic peaks of cerium (Ce), neodymium (Nd) and gadolinium (Gd) were observed for doped samples. The electron spin resonance (ESR) results demonstrated g-values ranging between 3.10 and 3.79 which indicated strong exchange interaction between nanoparticles, type of morphology, and crystalline nature of particles. These high g-values make Ni0.5Co0.5RE0.03Fe1.97O4 (RE = Ce, Nd, Gd) materials suitable for applications in high-frequency devices. The Mössbauer spectroscopy results revealed the formation of broadened Zeeman lines and quadrupole-split lines as well as the presence of the Fe3+ ions at B sites in the samples.

Break-Arc Erosion and Material Transfer Behavior of Pt–Ir and Pt–Ir–Y Electrical Contact Materials under Different Currents

In order to explore the influence of rare earth element Y on the electrical contact properties of Pt–Ir alloys, Pt–10Ir–Y and Pt–25Ir–Y were prepared via arc melting combined with thermal processing, and electrical contact experiments were carried out with a DC voltage of 24 V and current ranging from 5 A to 25 A. Comparative analyses were conducted to analyze the changes in the break arc duration and arc energy, as well as the contact resistance before and after the addition of Y. The arc erosion surface morphology was characterized, and the transfer behavior of the alloys was discussed. The results show that at 5 A and 25 A, adding Y improves the stability of the arc duration of the Pt–Ir alloy, but it increases the overall arcing energy and decreases the stability. The contact resistance of the Pt–Ir alloy shows a clear partitioning phenomenon; the partitioning phenomenon disappears after the addition of Y, and the contact resistance fluctuates around the average value. The material transfer direction of the Pt–Ir alloy is affected by the current change, while the material transfer direction of the Pt–Ir–Y alloy is always from cathode to anode. The research results provide a reference for the performance optimization of Pt–Ir alloys.

Influence of Rare Earth Elements and Radiation on Spectral Properties and Thermal Conductivity of Yttrium Aluminum Garnets and Phosphate Glasses

Influence of Rare Earth Elements and Radiation on Spectral Properties and Thermal Conductivity of Yttrium Aluminum Garnets and Phosphate Glasses

The influence of rare earth elements (Y, Sc) on the interfacial binding properties between the precipitation phases Fe2B, FeB and the matrix Fe in boron steel

Boron steel is a commonly used wear-resistant material in the metallurgical and mining industries. The performance of its hard precipitated phases and their coordination with the matrix are currently the main focus of attention. In this paper, the mechanical properties of the precipitated phases in boron steel were studied using first-principles calculations. Fe2B and FeB have high hardness, and the low-index surfaces with the lowest surface energy are (111). The low-index surface of the matrix Fe is (110). The interfacial properties between the matrix and the precipitated phases (Fe2B and FeB) were calculated. The interfacial energy of Fe(110)/FeB(111) is 0.3113 eV/Å2, and the interfacial energy of Fe(110)/Fe2B(111) is 0.3987 eV/Å2. The effects of rare earth elements Y and Sc on the interface bonding strength between (Fe2B, FeB) and matrix Fe were also examined. It was found that Y-doped Fe(110)/FeB(111) interface is more stable than that doped with Sc; however, the Sc-doped Fe(110)/Fe2B(111) interface is more stable than that doped with Y. The above calculation results indicate that rare earth elements play a promoting role in the micro-interface of boron steel, and the coordination between the precipitated phases and the matrix significantly improves the wear resistance of boron steel.

Catalytic behavior of Mo–Bi–Fe–Co–K–M–O (M=Ce, Gd, CeGd) catalysts for selective oxidation of isobutene

The further improvement of methacrolein (MAL) selectivity from isobutene (IB) oxidation is crucial and challenging. In this study, based on the typical Mo–Bi–Fe–Co–K–O mixed metal oxide, the rare earth element Gd-doped, Ce-doped and CeGd co-doped catalysts were prepared by co-precipitation strategy to increase the selectivity of MAL from 47.9% to 49.8%, 64.2% and 68.6%, respectively. In order to elucidate in-depth the promoting effect of Ce and/or Gd, various characterizations were utilized including X-ray diffraction patterns (XRD), Raman, X-ray fluorescence spectrometry (XRF), X-ray photoelectron spectroscopy (XPS), O2-temperature programmed desorption (O2-TPD), H2-temperature programmed reduction (H2-TPR), CO2-temperature programmed desorption (CO2-TPD), IB-temperature programmed desorption (i-C4-TPD) and in-situ IB-Fourier transform infrared spectroscopy (IB-FTIR). Both Ce and Gd finely regulate the bulk and surface structure of the catalyst, thus altering the redox ability, oxygen mobility and storage ability and basicity. Compared with Ce, Gd addition slightly regulates the variation of Co2+/Co3+ redox couples, greatly enhances the interaction among the components on the catalyst, thus only increases the content of surface oxygen species and has little effect on their mobility. While Ce-containing catalyst performs stronger oxygen storage and migration ability, thus leading to the overproduction of surface Odefect species, which are proposed to be the active sites for the production of MAL and COx. The CeGd co-doped catalyst possesses the proper content of surface Odefect species, thus exhibits much higher MAL selectivity. Moreover, the promoting mechanism of Ce and/or Gd over IB oxidation is proposed. Therefore, this work is helpful for understanding the influence of rare earth elements on the structure of mixed metal oxides and the olefin selective oxidation reaction.

Raman and X-ray photoelectron spectroscopy study on the influence of La2O3 on the melt structure of SiO2–CaO–Al2O3–MgO

In order to gain more insights into the influence of rare earth elements on the melt structure of SiO2–CaO–Al2O3–MgO glass ceramics, Raman and X-ray photoelectron spectroscopy techniques were used to study the influence of La2O3 on the Si–O/Al–O tetrahedron structure within SiO2–CaO–Al2O3–MgO–quenched glass samples in this study. Results showed that some Raman peak shapes at low frequencies (200–840 cm−1) changed significantly after the addition of La2O3, compared to the high frequency (840–1200 cm−1) region that corresponds to the [SiO4] structure, suggesting that the depolymerization of the low-frequency T–O–T (T=Si or Al) structure was more prevalent with La3+ addition. Besides, the depolymerization extent of the Si–O/Al–O tetrahedral network varied when the melt composition altered. Most notably, depolymerization is the most significant at a low CaO/SiO2 ratio (0.25) and a high Al2O3 content (8%). Meanwhile, La3+ can promote the transformation of Si–O–Si and Al–O–Al bonds to the Si–O–Al ones, thereby forming a complex ionic cluster network interwoven with Si–O and Al–O tetrahedrons.

The Enrichment Mechanism of REE at Sulfate and Methane Transition Zone (SMTZ) of the Northern Part of the South China Sea

Rare earth elements (REE) are important raw materials for electronic products and green-energy technology and deep-sea sediment as an important potential source of REE mineral. It is of great scientific significance to understand the influence of REE in deep-sea sediments. In this paper, thirty sediments samples and eleven sediments samples were collected at the site SH3 and SH1 of Shenhu area, respectively. The trace elements, major elements, and different Fe-Mn minerals were analyzed to investigate the role of anaerobic oxidation of methane (AOM) in the enrichment of rare earth elements in the marine sediments. The result showed that the content of ∑REE/Ti increased at the top of sulfate and methane transition zone (SMTZ) at site SH1 and SH3. Combined with the analysis of different forms of ferromanganese minerals and the REE patterns, it is inferred that there is little influence of terrigenous input to the REE content. In contrary, the REE-rich carbonate phase and REE-rich Fe-Mn oxides (hydroxides) phase have important contribution of REE enrichment at the top of SMTZ. Meanwhile, the calculations of the quantitative relationship between the REE-rich carbonate phase and REE-rich Fe-Mn oxides (hydroxides) phase also confirm this conclusion. And the AOM caused the decrease of the REE-rich Fe-Mn oxides (hydroxides) phase and increase of the REE-rich carbonate phase. This is the potential explanation of ∑REE/Ti enrichment at the top of SMTZ. This study is of great scientific significance for the study of REE enrichment mechanism in the methane seeps and provided a new sight of REE enrichment mechanism in deep-sea sediments.

Twin evolution in cast Mg-Gd-Y alloys and its dependence on aging heat treatment

Effects of rare-earth (RE) and precipitates on twin evolution in cast Mg-10Gd-3Y-0.5Zr (wt.%) (GW103) alloys of solid solution (T4) and aged (T6) states are investigated performing quasi-static room temperature compression tests and microstructural characterization. It is found that both {10–12} and {11–21} extension twins (ET1 and ET2) can appear in the T4 and T6 states but with different emergence sequences. As the aging heat treatment leads to consumption of RE solutes which could inhibit atomic shuffling required for nucleation of ET1 but not ET2, ET2 occurs prior to ET1 in the T4 state, and ET1 emerges before ET2 in the T6 state. The extension twins here mainly coordinate the plastic deformation through the non-Schmid effect. Our results shed light on the influence of RE elements on twin evolution in magnesium alloys and have implications in developing high-performance Mg-RE alloys.

Microstructure features of the BST/(Mg, Ln)-ceramic

Solid solutions of the composition Ba[Formula: see text](Mg, Ln)[Formula: see text][Formula: see text]TiO3 ([Formula: see text] = 0.01; 0.025; 0.04; [Formula: see text] = 0.20; 0.50; 0.80; Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tu, Yb) were prepared by two-stage solid-phase synthesis followed by sintering using conventional ceramic technology. The influence of rare-earth elements on the microstructure of the prepared ceramic samples was investigated. It was found that regardless of the type of modifiers introduced, the grain landscape of the studied solid solutions with different amounts of SrTiO3 is refined (in the initial system, the average grain size, [Formula: see text], at [Formula: see text] = 0.20 is 6 [Formula: see text]m; at [Formula: see text] = 0.50 is 4 [Formula: see text]m; at [Formula: see text] = 0.80 is 18 [Formula: see text]m) to crystallite sizes not exceeding (2-3) [Formula: see text]m, and compacted. The using of mechanical activation procedures leads to an even greater decrease in the size and an increase in the density of ceramics. The increasing in the concentration of modifiers in each group (within the considered range of dopant variation) against the background of such a fine-grained structure has little effect on the dynamics of changes in [Formula: see text]. It is concluded that it is advisable to use the data obtained in the development of functional materials based on BST/(Mg, Ln) and devices with the participation of these compositions.

Influence of rare earth elements on microstructure and strengthening mechanisms of Mg-12Gd-3Y-0.5Zr magnesium alloy

Mechanical properties of Mg-12Gd-3Y-0.5Zr (GW123K) including tensile strength and isothermal fatigue limit were tested by MTS810 system. Experimental results show that it has higher mechanical properties at different temperatures than other magnesium alloys without rare earth elements addition. Influence of rare earth elements on its microstructure and strengthening mechanisms are disscussed in this paper. SEM and TEM analysis indicates that rare earth elements additon leads to grain refinement and restricts grain boundary sliding and fatigue crack propogation.

Solubility of Rare Earth Oxides in Fused Alkali and Alkaline Earth Halides

Melts based on mixtures of alkali and/or alkaline earth halides are considered as prospective media for electrowinning rare earth metals as well as for pyrochemical reprocessing spent nuclear fuels. Fluoride or mixed fluoride-chloride baths can be operated at high temperatures yielding molten rare earth metals (REMs) thus simplifying separation of the metal and salt. One of the problems in using fluoride melts is possible formation of fluorine at the anode. This can be avoided by adding a rare earth oxide to the melt both as the source of REM and oxide ions. The latter will be oxidized to oxygen producing carbon mono- or dioxide at the anode. The limiting factor for feeding the electrolysis bath with REM oxides is their solubility in the halide melt.The aim of the present study was determining the effect of temperature and melt composition on solubility of REM oxides in fused halides. The experiments were performed in CaCl2–CaF2 mixtures containing 20 or 75 mol. % CaF2; BaCl2–BaF2 mixtures containing 15 or 73 mol. % BaF2; equimolar CaF2–BaF2 mixture and NaCl–NaF eutectic mixture (34 mol. % NaF). Solubility of REM oxides was determined by the method of isothermal saturation. Time required for reaching the equilibrium between solid REM oxides and fused salts was determined in a preliminary set of experiments. To compare the behavior of 4f- and 5f-elements, solubility of uranium dioxide was also measured.The measurements were performed at the temperatures up to 1400 oC under argon atmosphere. The lower limit of the temperature range varied from 700 to 1100 oC depending on the melting temperatures of the salt mixtures used. Oxides of yttrium, lanthanum, cerium, praseodymium, neodymium and samarium were selected for the study. To assess a possible mutual influence of rare earth elements on solubility of their oxides in fused salts the solubility of a mixture of REM oxides was determined in a separate series of experiments and concentrations of individual REMs in the melt was determined.Solubility of REM oxides increased with increasing temperature and an example of effect of temperature on solubility of neodymium oxide in various melts is shown in Fig.Fig. Concentration of neodymium in alkali and alkaline halide based melts saturated with Nd2O3. Melt: CaCl2–CaF2 20 mol. % (1); CaCl2–CaF2 75 mol. % (2); BaCl2–BaF2 73 mol. % (3); BaCl2–BaF2 15 mol. % (4); CaF2–BaF2 50 mol. % (5; and NaCl–NaF 34 mol. % (6). Figure 1

Influence of Rare Earth Element (Y) on Microstructure and Corrosion Behavior of Hot Extrusion AZ91 Magnesium Alloy.

The influence of rare earth element (RE) Y on the microstructure and corrosion behavior of extruded AZ91 Mg alloy was surveyed via morphology characterization and corrosion performance measurements. The results indicate the corrosion resistance of the transversal section of AZ91 Mg alloy containing Y was improved compared with AZ91 Mg alloy without Y. The corrosion resistance of the longitudinal section of AZ91 Mg alloy with Y was lower than that of AZ91 Mg alloy without Y. The change of corrosion resistance can be attributed to the dispersion and volume fraction of the second phase, the effect of cathodic reduction rate, and the refined second phase.

Influence of salinity and rare earth elements on simultaneous removal of Cd, Cr, Cu, Hg, Ni and Pb from contaminated waters by living macroalgae

Potentially toxic elements (PTEs) are of major concern due to their high persistence and toxicity. Recently, rare earth elements (REEs) concentration in aquatic ecosystems has been increasing due to their application in modern technologies. Thus, this work aimed to study, for the first time, the influence of REEs (lanthanum, cerium, praseodymium, neodymium, europium, gadolinium, terbium, dysprosium and yttrium) and of salinity (10 and 30) on the removal of PTEs (Cd, Cr, Cu, Hg, Ni and Pb) from contaminated waters by living macroalgae (Fucus spiralis, Fucus vesiculosus, Gracilaria sp., Osmundea pinnatifida, Ulva intestinalis and Ulva lactuca). Experiments ran for 168 h, with each macroalga exposed to saline water spiked with the six PTEs and with the six PTEs plus nine REEs (all at 1 μmol L−1) at both salinities. Results showed that all species have high affinity with Hg (90–99% of removal), not being affected neither by salinity changes nor by the presence of other PTEs or REEs. Cd showed the lowest affinity to most macroalgae, with residual concentrations in water varying between 50 and 108 μg L−1, while Pb removal always increased with salinity decline (up to 80% at salinity 10). REEs influence was clearer at salinity 30, and mainly for Pb. No substantial changes were observed in Ni and Hg sorption. For the remaining elements, the effect of REEs varied among algae species. Overall, the results highlight the role of marine macroalgae as living biofilters (particularly U. lactuca), capable of lowering the levels of top priority hazardous substances (particularly Hg) and other PTEs in water, even in the presence of the new emerging contaminants - REEs. Differences in removal efficiency between elements and macroalgae are explained by the contaminant chemistry in water and by macroalgae characteristics.

Influence of rare earth elements on the structure and properties of powders based on zirconium dioxide during consolidation

Zirconium oxide powders with different contents of REE concentrate (La, Nd, Pr) in an amount from 25 to 35 mol. % were synthesized by the method of reverse chemical deposition. The effect of the annealing temperature in the range of 600–1200 ° C on the phase transformations of the synthesized powders has been investigated by Raman spectroscopy. It was found that the formation of REE zirconates with a pyrochlore structure occurs after annealing at a temperature of 1000 ° C. At higher annealing temperatures, the presence of tetragonal ZrO2 was noted in the samples with a lower concentrate content in the phase composition. A study of the influence of the sintering temperature of 1400-1600 °C on the densification processes, phase composition and microstructure of ceramic materials based on REE zirconates has been carried out. It has been shown that the densification processes proceed most slowly in a ceramic material with 35 mol.% of rare-earth oxides, and at all sintering temperatures it has a stable phase composition, consisting mainly of rare-earth zirconates with a pyrochlore structure.

Structural features of titanium, aluminum and magnesium alloys with rare earth elements

The influence of rare earth elements (REE) on titanium, aluminum and magnesium, as well as doping systems based on them, is considered. The general regularities of REE influence on the mentioned titanium, aluminum and magnesium are revealed.

Prenatal exposure of rare earth elements cerium and ytterbium and neonatal thyroid stimulating hormone levels: Findings from a birth cohort study

BackgroundPrior studies have suggested exposure to heavy metals and endocrine disrupting chemicals could disturb the homeostasis of thyroid stimulating hormone (TSH), but no epidemiology study concerning the influence of rare earth elements (REE) exposure during pregnancy on neonatal TSH levels. The present study aimed to investigate the relationships between prenatal REE exposure and neonatal TSH levels. MethodsA total of 7367 pregnant women were recruited from Wuhan Children’s Hospital between September 2012 and October 2014 in Wuhan, China. Urinary concentrations of cerium (Ce), and ytterbium (Yb) were measured by inductively coupled plasma mass spectrometry (ICP-MS). Immunofluorescence assay was used to detect neonatal TSH levels. The associations between REE exposure and neonatal TSH levels were evaluated using multivariate linear regression models. ResultsThe geometric means of maternal urinary Ce and Yb concentrations were 0.060 μg/g creatinine and 0.025 μg/g creatinine, respectively. The results showed that per doubling of maternal urinary Ce and Yb were associated with 4.07% (95% CI: −5.80%, −2.31%), 5.13% (95% CI: −6.93%, −3.30%) decreased neonatal TSH levels respectively in the adjusted model. Sex stratified analysis demonstrated that the decreased neonatal TSH levels were observed both in male infants and female infants, and the decrease was greater in male infants in urinary Ce. There were no significant interactions between maternal urinary Ce, Yb and infant sex (Ce: P for interaction = 0.173, Yb: P for interaction = 0.967). ConclusionsOur findings demonstrated that increased maternal urinary Ce and Yb were associated with decreased neonatal TSH levels. Further researches from different populations are warranted to verify the association and to explore the mechanisms.

Redox Recycling-Triggered Peroxidase-Like Activity Enhancement of Bare Gold Nanoparticles for Ultrasensitive Colorimetric Detection of Rare-Earth Ce3+ Ion.

Although it has been demonstrated that rare-earth elements (REEs) disturb and alter the catalytic activity of numerous natural enzymes, their effects on nanomaterial-based artificial enzymes (nanozymes) have been seldom explored. In this work, the influence of REEs on the peroxidase-like activity of bare gold nanoparticles (GNPs) is investigated for the first time, and a new type of Ce3+-activated peroxidase mimetic activity of GNPs is obtained. The introduced Ce3+ can be bound to the bare GNP surface rapidly through electrostatic attraction, after which it donates its electron to the bare GNP. As H2O2 is a good electron scavenger, more •OH radicals are generated on the surfaces of the bare GNPs, which can considerably enhance TMB oxidation. Due to its redox cycling ability, the activation effect of Ce3+ is proved to be more efficient in comparison to those of the other reported metal ion activators (e.g., Bi3+, Hg2+, and Pb2+). In addition, it is determined that Ce3+ should directly contact with the gold core to trigger its activation effect. When the surface states of the bare GNPs are altered, the Ce3+-stimulated effect is strongly inhibited. Furthermore, a novel colorimetric method for Ce3+ is developed, on the basis of its enhancing effect on the peroxidase mimetic activity of bare GNPs. The sensitivity of this newly developed method for Ce3+ is excellent with a limit of detection as low as 2.2 nM. This study not only provides an effective GNP-based peroxidase mimic but also contributes in realizing new applications for nanozymes.