CeO2 Lattice Research Articles

Niobium Modification of CeO2 Tuning Electron Density of Nickel-Ceria Interfacial Sites for Enhanced CO2 Methanation.

CO2 methanation has attracted considerable attention as a promising strategy for recycling CO2 and generating valuable methane. This study presents a niobium-doped CeO2-supported Ni catalyst (Ni/NbCe), which demonstrates remarkable performance in terms of CO2 conversion and CH4 selectivity, even when operating at a low temperature of 250 °C. Structural analysis reveals the incorporation of Nb species into the CeO2 lattice, resulting in the formation of a Nb-Ce-O solid solution. Compared with the Ni/CeO2 catalyst, this solid solution demonstrates an improved spatial distribution. To comprehend the impact of the Nb-Ce-O solid solution on refining the electronic properties of the Ni-Ce interfacial sites, facilitating H2 activation, and accelerating the hydrogenation of CO2* into HCOO*, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis and density functional theory (DFT) calculations were conducted. These investigations shed light on the mechanism through which the activity of CO2 methanation is enhanced, which differs from the commonly observed CO* pathway triggered by oxygen vacancies (OV). Consequently, this study provides a comprehensive understanding of the intricate interplay between the electronic properties of the catalyst's active sites and the reaction pathway in CO2 methanation over Ni-based catalysts.

Effect of acid sites modification on the catalytic combustion of 1,2-dichloroethane: Revealing the synergy between NbOx and CeO2

1,2-Dichloroethane are primarily sourced from the emissions of the chlor-alkali industry, resulting in severe pollution of soil, air, and water. In this work, Nb/CeO2 catalysts were prepared by impregnation method, and their performance for EDC oxidation was evaluated. The addition of Nb improved the activity, selectivity, and stability of CeO2. Nb was highly dispersed on CeO2 surface in the form of NbOx, and partially entered the lattice of CeO2. This caused lattice distortion and more surface defects, thereby increasing the number of oxygen vacancies. NbOCe bonds formed in between Nb and CeO2 weakened the CeO bonds and enhanced lattice oxygen mobility. The presence of NbOx increased the number of Lewis acid (NbO) and Brønsted acid (Nb-OH) sites, which facilitated the cleavage of CCl and CC bonds. Increased acidity promoted the removal of Cl species in the form of HCl and effectively mitigated the chlorine poisoning of CeO2. In-situ DRIFTS results indicated that EDC oxidation on Nb/CeO2 catalysts followed a Mars-van Krevelen mechanism and progressed via the pathway of alcoholate → formate/methoxy → COx.

Oxygen vacancies mediated changes in ferromagnetic, optical, Photoluminescent and electronic structure properties of Ho-doped CeO2 nanoparticles

The undoped CeO2 and Ce1-xHoxO2 (x = 0.03, 0.05 and 0.07) nanoparticles prepared using microwave assisted co-precipitation route are investigated using X-Ray Diffraction (XRD), UV–Vis–NIR, Raman, photoluminescence, X-ray Photoelectron Spectroscopy (XPS) and SQUID-VSM magnetometer. The XRD validates the inclusion of Ho3+ at the Ce3+/Ce4+ site while maintaining the crystal structure with development of defects and oxygen vacancies with expansion of the CeO2 nanolattice. The composition of the elements with desired stoichiometry is confirmed by Energy Dispersive X-ray spectra analysis. The absorption spectroscopy analysis reports the Urbach energy along with refractive index increases with Ho3+ doping and the optical band gap is decreased indicating red shift. All the nanoparticles are subjected to PL investigations to ascertain the oxygen vacancy and defect structure of nanoparticles. Raman active modes at ∼500 - 630 cm−1 verifies the existence of oxygen vacancies (Vo)., which are seen to rise with concentration of Ho-doping in the CeO2 lattice. When Ce4+ transforms into Ce3+, oxygen vacancies are generated in the lattice to maintain the charge neutrality, as can be seen by the Ce-3d, O-1s, and Ho-4d core level XPS spectra. To demonstrate that Ho3+ doping favours ferromagnetic ordering in the CeO2 lattice, the magnetic properties using the Bound Magnetic Polaron model and F centre exchange mechanism are discussed. The development of various complexes that involve host and doped cations are mediated by Vo suggests the existence of F0, F+, and F2+ centres. The weak ferromagnetic behaviour in Ho3+-doped CeO2 nanoparticles reinforce the relationship between Vo to explain the observed magnetic properties of nanoparticles.

Bi-doped CuCeO2−x nanorod catalysts for photothermal CO-PROX in H2-rich streams: Enhanced oxygen vacancy and light absorption capacity

The wide band gap of ceria limited the light absorption and photothermal conversion of copper-ceria catalyst for photothermal preferential oxidation of CO (CO-PROX). In the present work, doping Bi element was adopted to regulate the energy band and catalytic performance of CuCeO2−x nanorod catalysts for photothermal CO-PROX. Bi/CuCeO2−x nanorods were synthesized by co-precipitation hydrothermal and deposition precipitation method. The Bi/CuCeO2−x catalyst with the molar ratio of Bi/Ce 2.5% exhibited the best catalytic performance and the CO conversion reached 90% under 2.5 suns with a surface temperature of 120 °C. The doped Bi species were incorporated into the CeO2 lattice and promoted the formation of oxygen vacancy sites and the strong Cu-Ce interaction, as revealed by XRD, XPS, Raman and H2-TPR results. In addition, doping Bi reduced the band gap of ceria nanorod from 2.77 to 2.47 eV and remarkably enhanced the UV–vis light response and photogenerated carrier separation of Bi/CuCeO2−x-2.5.

Room‐Temperature Synthesis of a Compositionally Complex Rare‐Earth Carbonate Hydroxide and its Conversion into a Bixbyite‐Type High‐Entropy Sesquioxide

AbstractIn the present work, the solvent‐deficient synthesis of the high‐entropy rare‐earth carbonate hydroxide RE(CO3)(OH) (RE=La, Ce, Pr, Nd, Sm, and Gd) and its thermal conversion into bixbyite‐type sesquioxide RE2O3 are reported for the first time. The high‐entropy rare earth carbonate hydroxide was prepared via mechanochemical reaction of the corresponding metal nitrate hydrates with ammonium hydrogen carbonate followed by the removal of the NH4NO3 by‐product. Calcination of the carbonate hydroxide precursor in ambient atmosphere at temperatures in the range from 500 to 1000 °C led to the high‐entropy rare earth sesquioxide which exhibited a bixbyite‐type structure ( ) independent of the calcination temperature. Transmission electron microscopy (TEM) investigation revealed the homogeneous distribution of all six rare earth cations in the high‐entropy sesquioxide lattice, however, with some compositional variation between individual grains. The bixbyite‐type structure may be considered as the result of heavy doping of the fluorite‐type CeO2 lattice with the other rare earth cations, which leads to a high concentration of oxygen vacancies, as revealed by electron diffraction and Raman spectroscopy data. The solvent‐deficient synthesis method used in the present study is considered as a valuable, straightforward and easily up‐scalable method to synthesize compositionally complex oxide ceramics.

The defects of structural and phase transformations in polycrystalline cerium dioxide under heating in vacuum and in air

Structural changes in cerium dioxide, when heated in vacuum in the range of 25‒1600 °C, in air in the range of 25‒1500 °C, and during successive annealing in the range of 1600‒2100 °C in air, followed by quenching in water, were studied. In the crystal lattice of CeO2‒х, the F → F1 phase transformation in vacuum proceeds in the range of 1100‒1600 °C; additionally, at 1200 °C, X-ray lines of the C-type Ce2O3 phase appear. The thermal expansion coefficient of phases of the fluorite type F and F1 in the range of 25‒1500 °C in air, as well as phases of the fluorite type F, F1 and type C Ce2O3 in the range of 25‒1600 °C are determined in vacuum and their dependence on the change in the oxygen content in the CeO2‒х crystal lattice was found. The kinetic conditions for reduction of cerium dioxide in vacuum and oxidation in air are different. The cubic structure of the fluorite type F CeO2‒х, when the samples are heated in air, is preserved up to 1800 °C with the content of anionic vacancies, at 1900 °C the transformation F → F1 occurs. The formation of loops, edge and screw dislocations in the structure of cerium dioxide grains after annealing of samples in the range of 1900‒2100 °C in air were discovered for the first time. The decomposition of the structure F1 into cerium oxide phases of types F and C proceeds at 2100 °C along the height and boundaries of screw dislocations. It was found that fragments of the C-type phase of cerium oxide are located on loops along the height of screw dislocations, which indicates the movement and evaporation of these fragments. When the samples are oxidized at 1600 °C in air, the black-colored C Ce2O3‒х phase in a gradient of different concentrations moves along certain trajectories to opposite ones. grain boundaries, abuts against dislocation loops, bends them, and oxidizes to phases F1 and F. In the structure of polycrystalline cerium dioxide, when heated in vacuum and in air, certain concentrations of defects control phase transformations.

MOCVD deposited double-sided CeO2 buffer layer for YBCO superconducting film grow on R-plane Al2O3 substrate

Double-sided CeO2/YBCO films were grown on the double-sided polishing R-plane Al2O3 substrate using MOCVD technology. The effects of deposition parameters of the MOCVD setup on the structural orientation and surface morphology of CeO2 buffer layers grown on sapphire substrates were investigated. A series of CeO2 buffer layers were prepared by varying the substrate temperature and oxygen flow rate. The results show that when the substrate temperature is lower than 750 °C and the oxygen flow rate is lower than 400 sccm, CeO2 films is grown in a mixed (00l) and (111) orientations, and when the substrate temperature is 750 °C-840 °C and the oxygen flow rate is higher than 400 sccm, the CeO2 films are grown with a single (001) orientation. When the deposition temperature was 800 °C and the oxygen flow rate was 800 sccm, the CeO2 buffer layer structure had the best orientation with double-sided ω-scan FWHM of 0.019° and 0.02°; the FWHM of double-sided Ф-scan were 1.8° and 1.7°; the RMS roughness on both sides measured by AFM were 1.28 nm. YBCO films grown on this buffer layer have good c-axis epitaxial orientation, and the test results of the pole figure show an in-plane rotation of 45° between YBCO and CeO2 lattices. Thus, the obtained YBCO film has a critical current density of 2 MA/cm2, indicating that the films can be prepared to meet the needs of microwave devices using R-plane Al2O3 substrates.

Enhanced photocatalytic performance of Mn-doped CeO2 nanoribbons for VOCs degradation: Investigating charge rearrangement and local electric field effects

In this study, we investigate Mn-doped CeO2 nanoribbons as photocatalysts to address the issue of performance enhancement in volatile organic compounds (VOCs) removal. Our primary focus centers on elucidating the interplay between charge rearrangement and local electric field (LEF) effects to uncover how these key factors collectively contribute to the improved photocatalytic performance. The successful doping of Mn atoms into the CeO2 lattice resulted in a strong dopant/matrix interaction effect. In situ XPS and density functional theory (DFT) calculations confirmed significant local charge rearrangement due to the dopant-induced local electric field, promoting charge carrier separation. The Mn dopant facilitated the generation of superoxide and hydroxide radicals. DFT simulations showed that Mn doping promoted VOCs adsorption on CeO2, favoring the subsequent oxidation process. The Mn-doped CeO2 nanoribbons achieved enhanced photodegradation performance of HCHO and CH3COCH3 compared to CeO2. This work aims to provide guidance and insights for the development of advanced photocatalysts.

The impact of redox annealing on intrinsic properties and fluoride adsorption performance of CeO2 nanomaterials

The presence of excess fluoride ions in drinking water has raised widespread concerns, necessitating the development of effective methods for its removal. Cerium dioxide (CeO2) holds promise as a selective adsorbent for fluoride ions, due to its exceptional affinity for fluoride and stability across a wide pH range. However, the impact of intrinsic properties of CeO2 on its adsorption characteristics and mechanisms remains unclear. In this study, we prepared a range of CeO2 materials with diverse intrinsic properties by adjusting the annealing temperature and atmosphere. Through a series of characterization techniques, we discovered a correlation between the content of oxygen vacancies, Ce(III) species, and surface hydroxyl groups (–OH), all of which decreased simultaneously with increasing air annealing temperature. With respect to the adsorption performance, the highest fluoride adsorption capacity of 111.1 mg g−1 was observed in un-CeO2, representing the nanomaterials with the highest oxygen vacancies. This capacity gradually decreased to 29.1 mg g−1 in 800-CeO2. Following fluoride adsorption, the oxygen vacancy density, Ce(III) content, and surface –OH content of all CeO2 materials decreased. When CeO2 materials were annealed in H2 for 1 h, the F− adsorption density increased due to the formation of more oxygen vacancies and surface –OH. Based on our findings, we conclude that oxygen vacancies play a critical role in determining whether fluoride ions can successfully exchange with surface –OH groups and enter the crystal lattice of CeO2, which significantly affects the adsorption performance. The pivotal role of oxygen vacancies, as proposed in this study, provides a valuable direction for future research aimed at enhancing the fluoride adsorption performance of CeO2.

Mn-modified near-surface atomic structure of CeO2 nanorods for promoting catalytic oxidation of auto-exhaust carbon particles

Herein, we synthesized the well-defined catalysts of Mn-decorated single-crystal CeO2 nanorod (Mn/CeO2) with dominantly exposed {110} facets by incipient wetness impregnation method. Surface-modified Mn atoms can diffuse into the crystal lattice of CeO2-{110} facet to form Mn-O-Ce bond chains. The heteroatomic interfacial oxygen atoms in Mn-O-Ce bond chains as active oxygen species have a high-efficient performance, and resulting oxygen vacancy (Ov) sites can promote the adsorption and activation properties for O2. Mn/CeO2-10 catalyst exhibits superior catalytic activities and high stability. The related characterizations and DFT calculations results reveal that the Mn2+-Ov-Ce3+ active sites can decrease activation energy of O2 and desorption energy of NO2 in processes of NO oxidation to NO2, which is the crucial steps of NO2-assisted mechanism for soot oxidation. This work provides a new inspiration for rational modification of the near-surface atomic structure to obtain efficient catalysts for removal of soot or other pollutions.

The Mn/Yb/Er triple-doped CeO2 nanozyme with enhanced oxidase-like activity for highly sensitive ratiometric detection of nitrite

Long-term excessive intake of nitrite (NO2−) poses a great threat to human health, needing a simple and fast method to detect NO2− in food. Herein, via a simple and feasible strategy, Mn/Yb/Er triple-doped CeO2 nanozyme (Mn/Yb/Er/CeO2) was synthesized for highly sensitive ratiometric detection of nitrite. By doping Mn, Yb, Er into CeO2 lattice structure, Mn/Yb/Er/CeO2 nanozyme showed enhanced oxidase-like activity, obtaining a higher density of oxygen vacancy and a higher ratio of Ce3+ to Ce4+ than that of CeO2. The 3,3′,5,5′-tetramethylbenzidine (TMB) can be effectively oxidized by Mn/Yb/Er/CeO2 to produce the oxidized TMB (oxTMB), showing a significant absorption signal at 652 nm. Additionally, nitrite can react with oxTMB to produce yellow diazotized oxTMB, which is accompanied by an elevated absorption signal at 445 nm and a decreased absorption signal at 652 nm. Thus, based on the oxidase-mimetic activity of Mn/Yb/Er/CeO2 and the diazotization reaction between NO2− and oxTMB, a ratiometric colorimetric assay was established for NO2− detection in food. Furthermore, by integrating Mn/Yb/Er/CeO2 with a smartphone, a colorimetric smartphone-sensing platform was successfully fabricated for visualization and quantitative detection of NO2−. Notably, this two-detection mode showed excellent sensitivity, selectivity, reliability and practicability in monitoring the NO2− in real samples, impling its great potential for food safety.

Low-Temperature Plasma-Assisted Catalytic Dry Reforming of Methane over CeO2 Nanorod-Supported NiO Catalysts in a Dielectric Barrier Discharge Reactor.

Nonthermal plasma (NTP)-assisted catalytic dry reforming of methane (DRM) is considered a powerful single-stage reaction mechanism because of its ability to activate normally stable CO2 and CH4 at a low temperature under ambient conditions. The thermodynamic barrier of DRM requires a high operating temperature (>700 °C), which can be reduced by nonequilibrium plasma. Herein, we present a method for the wet-impregnation synthesis of CeO2 nanorod (NR)-supported 5 and 15 wt % NiO catalysts for efficient NTP-promoted DRM with an applied power in the range of 24.9-25.8 W (frequency: 20 kHz), a CH4:CO2 feed gas ratio of 100:250 sccm, and a total flow rate of 350 sccm. The presence of NTP dramatically increased the reaction activity, even at 150 °C, which is usually inaccessible for thermally catalyzed DRM. The CH4 and CO2 conversion reaches a maximum of 66 and 48%, respectively, at 500 °C with the 15 wt % NiO/CeO2 NR catalyst, which are much higher than the values obtained for the 5 wt % NiO/CeO2 NR catalyst under the same conditions. According to the X-ray photoelectron spectroscopy profile for 15 wt % NiO/CeO2 NR, a higher concentration of NiO on CeO2 increases the proportion of Ce3+ in the catalyst, suggesting enhanced oxygen vacancy concentration with an increased amount of NiO loading. Additionally, a higher NiO loading promotes a higher rate of replacement of Ce4+ with Ni2+, which generates more oxygen vacancies due to the induced charge imbalance and lattice distortion within the CeO2 lattice. As a result, it can be inferred that the incorporation of Ni ions into the CeO2 structure resulted in inhibited growth of CeO2 crystals due to the creation of a NixCe1-xO2-α solid solution and the production of oxygen vacancies.

Cu docking-activated Nb incorporation in multivariate CuO-Nb2O5/CeO2 catalysts for selective reduction of NOx with NH3

Improving the low-temperature selective catalytic reduction of NOx with NH3 (NH3-SCR) meanwhile maintaining N2 selectivity are challenging in the field of catalysis. Herein, we showcase the fabrication of the synergistic catalytic sites in the CuO-Nb2O5/CeO2 catalysts. Impressively, the CuO-Nb2O5/CeO2 is characteristic with abundant oxygen vacancies at the interfacial regions, which facilitate the redox reaction between Ce3+, Nb5+ and Cu2+ with the assistance of surface oxygen, exhibiting high NH3-SCR activity, N2 selectivity and wide temperature window at a gas hourly space velocity of 150,000 h−1. Contrast experiments, EXAFS analysis, in situ infrared and Raman spectroscopy, and theoretical calculations indicate that the introduction of proper copper ions in the CeO2 lattice induces the structure distortion of surface CeO2, improving more niobium ions incorporation into the CeO2. The embedded Nb synergizes Cu and Ce to evoke the generation of newly adsorptive sites for NOx and NH3, thus contributing to the NH3-SCR reaction.

Photoelectron spectroscopy of ceria: Reduction, quantification and the myth of the vacancy peak in XPS analysis

Primarily due to its inherent redox chemistry, ceria (CeO2) is of use in many diverse areas of research. However, there is a wealth of misinterpretation of the oxygen spectra when discussing the result of damage or reduction to the CeO2 lattice, especially with regard to a signal in this region attributed to oxygen vacancies. In this paper, it is shown that this peak cannot be due to vacancies and that a better understanding of the changes in stoichiometry of CeO2 is best viewed from that of the Ce(III) component when considered in tandem with the O 1s signal.

Crack formation and optical properties in 175 MeV Au13+ ion beam irradiated CeO2 thin films

CeO2 thin films have been deposited on fused silica substrates using RF-sputtering technique. 175 MeV Au13+ ions beam with two different fluences, 1 × 1012 ions/cm2 and 5 × 1012 ions/cm2, have been applied to modify the structural, surface and optical properties of CeO2 thin films. X-ray diffraction (XRD), atomic force microscopy (AFM), UV–visible absorption and photoluminescence (PL) measurements have been performed to investigate the 175 MeV Au13+ ion-irradiation induced changes in CeO2 thin films. The irradiated films show the formation of nanocrystalline granulizes on the film surface. The mud like cracks have been evolved at the ion-fluence of 5 × 1012 ion/cm2. The modifications in the optical and structural properties and the formation of cracks have been studied under the light of 175 MeV Au13+ ion irradiation and energy loss process into CeO2 lattice.

Novel Mesoporous and Multilayered Yb/N-Co-Doped CeO2 with Enhanced Oxygen Storage Capacity.

A cubic fluorite-type CeO2 with mesoporous multilayered morphology was synthesized by the solvothermal method followed by calcination in air, and its oxygen storage capacity (OSC) was quantified by the amount of O2 consumption per gram of CeO2 based on hydrogen temperature programmed reduction (H2-TPR) measurements. Doping CeO2 with ytterbium (Yb) and nitrogen (N) ions proved to be an effective route to improving its OSC in this work. The OSC of undoped CeO2 was 0.115 mmol O2/g and reached as high as 0.222 mmol O2/g upon the addition of 5 mol.% Yb(NO3)3∙5H2O, further enhanced to 0.274 mmol O2/g with the introduction of 20 mol.% triethanolamine. Both the introductions of Yb cations and N anions into the CeO2 lattice were conducive to the formation of more non-stoichiometric oxygen vacancy (VO) defects and reducible-reoxidizable Cen+ ions. To determine the structure performance relationships, the partial least squares method was employed to construct two linear functions for the doping level vs. lattice parameter and [VO] vs. OSC/SBET.

Hydrogen production by the catalytic decomposition of ammonia over a Ru/SiCeOx catalyst: The synergistic effect of Si addition

Controlling active metal–support interaction is critical in the catalytic decomposition of ammonia (NH3). In this study, we investigated the generation of oxygen vacancies in the SiCeOx support by Si addition and the increase in catalytic performance for the decomposition of NH3 by their interaction with Ru. The Si content in the Ru/SiCeOx catalysts was controlled by glassware elution during the precipitation of Ce(NO3)3 at a high pH level (10.5) by applying different aging temperatures and times. The formation of oxygen vacancies by the insertion of Si4+ into the CeO2 lattice was characterized by O2-pulse experiments as well as Raman and X-ray photoelectron spectroscopy analyses. The effect of oxygen vacancies on the adsorption strengths of hydrogen and nitrogen on Ru was characterized by H2-temperature-programmed reduction and NH3-temperature-programmed desorption. The correlation between NH3 conversion, oxygen vacancy content, and nitrogen desorption temperature was experimentally proven.

Antimicrobial activity of Cobalt doped Cerium Oxide (Co-CeO2) nanoparticles against selected food pathogens

This present work is to investigate the antibacterial activity of CeO2 nanoparticles on five foodborne pathogens. Low-temperature solid-state reactions were used to create co-doped CeO2 nanoparticles (Co-CeO2 NPs). In the current work, the impact of Co-doping on polycrystalline CeO2 samples synthesized using the co-precipitation method at room temperature for Co-doping concentrations of 0.5%, 1%, 3%, and 5% is discussed. Rietveld refinement of the X-ray diffraction patterns confirms that the Co-doped CeO2 samples have a face-centred cubic structure. This shows that the Co ions have been successfully integrated into the CeO2 lattice. Also, the UV-Vis-NIR absorption spectra confirm that redshifts do happen in the Co-doped CeO2 samples, which shows that the band gap energy decreases as the number of Co ions grows. In an antibacterial test against five pathogenic microbes, S. aureus, M. luteus, Enterobacter aerogenes, S. typhi, and Pseudomonas aeruginosa, Co-doped cerium oxide nanoparticles significantly slowed the growth of all five pathogens, both in liquid and solid growth conditions. These results show that Co-doped CeO2 nanoparticles have strong antibacterial properties against foodborne pathogens. This suggests that they could be used as promising bionanomaterials for in vivo therapeutic uses.

The enhancement of benzene total oxidation over RuxCeO2 catalysts at low temperature: The significance of Ru incorporation

Catalytic oxidation is considered to be the most efficient technology for eliminating benzene from waste gas. The challenge is the reduction of the catalytic reaction temperature for the deep oxidation of benzene. Here, highly efficient RuxCeO2 catalysts were utilized to turn the number of surface oxygen vacancies and Ce–O–Ru bonds via a one-step hydrothermal method, resulting in a preferable low-temperature reducibility for the total oxidation of benzene. The T50 of the Ru0.2CeO2 catalyst for benzene oxidation was 135 °C, which was better than that of pristine CeO2 (239 °C) and 0.2Ru/CeO2 (190 °C). The superior performance of Ru0.2CeO2 was attributed to its large surface area (approximately 114.23 m2·g−1), abundant surface oxygen vacancies, and Ce–O–Ru bonds. The incorporation of Ru into the CeO2 lattice could effectively facilitate the destruction of the CeO bond and the facile release of lattice oxygen, inducing the generation of surface oxygen vacancies. Meanwhile, the bridging action of Ce–O–Ru bonds accelerated electron transfer and lattice oxygen transportation, which had a synergistic effect with surface oxygen vacancies to reduce the reaction temperature. The Ru0.2CeO2 catalyst also exhibited high catalytic stability, water tolerance, and impact resistance in terms of benzene abatement. Using in situ infrared spectroscopy, it was demonstrated that the Ru0.2CeO2 catalyst can effectively enhance the accumulation of maleate species, which are key intermediates for benzene ring opening, thereby enhancing the deep oxidation of benzene.

Correlation of oxygen defects, oxide-ion conductivity and dielectric relaxation to electronic structure and room temperature ferromagnetic properties of Yb3+ doped CeO2 nanoparticles

Ce1-xYbxO2 nanoparticles synthesized using co-precipitation route were studied for properties like structural, optical, impedance and X-ray Photoelectron Spectroscopy. Existence of cubic fluorite structure found intact with heterogeneous aggregation and spherical surface morphology. Red-shifted energy gap along with formation of defects and oxygen vacancies was confirmed with UV–Vis and Photoluminescence analyses. XPS analyses were undertaken to observe the chemical states 2+ and 3+ of Yb and 3+ and 4+ of Ce cations. The magnetization results demonstrated improved ferromagnetic ordering for varying Yb doping, explained with Bound Magnetic Polarons model and F-Centre Mechanism for creation of distinct complexes, Ce4+-Vo-Ce3+ or Yb3+-Vo-Ce3+ in the CeO2 lattice. All samples' dielectric permittivity and modulus were measured in the 120 Hz–100 kHz frequency range. The ∈′ (f) and ∈″(f) plots show two distinct regions: a plateau zone at high frequency and low frequency dielectric dispersion region. These nanoparticles could be employed for photolytic, optoelectronics and energy storage applications.