First-principles investigation of Ce, V, and Bi dopant composition and concentration effects in Nb-O and Ti-Nb-O oxide anodes: Enhancing lithium-ion battery performance

Structural, optical and electrical properties of cerium and gadolinium doped CdO thin films

SnO2 nanoparticles accompanied by various concentrations of Ce as dopant material were prepared to extend the optical absorption spectrum near the visible spectrum. The Ce-doped SnO2 NPs at 0.5% (w/w) exhibit significantly higher photocatalytic ability compared to pure SnO2. This enhancement has potential applications in environmental remediation, energy storage, and optoelectronic devices. The microstructures and optical properties of the prepared samples were characterized by XRD, FTIR, EDS, SEM, and UV–vis DRS. The results showed that the nanoparticles are in the tetragonal rutile SnO2 phase. Increasing Ce concentration (over 0.5% (w/w)) shifted the absorption edge towards higher wavelengths and the band gap energy drops from 3.620 to 3.031 eV. The FTIR spectrum confirmed the O–Sn–O bond information in the synthesized samples. The SEM images showed the formation of nearly spherical nanoparticles. Ce-doped SnO2 NPs have smaller primary particles than SnO2 NPs. Reduction in the band gap due to an increase in defects by Ce doping is found and confirmed by the UV–Vis spectra. The existence of Sn and O elements was confirmed by the observed EDS spectra. A plausible photocatalytic mechanism was proposed for the degradation of Methylene blue under UV light to examine the photocatalytic activity of SnO2 and Ce-doped SnO2 NPs photocatalyst. The Ce-doped SnO2 NPs display improved photocatalytic activity compared to SnO2. The influence of Ce concentration doping on the electrical properties was observed at room temperature. Impedance decreases with the frequency and Ce concentration while ac conductivity is increases with the frequency and Ce concentration. The dielectric constant and the dielectric loss rise up with the Ce doping and decrease with the frequency. Among the synthesized samples, the Ce-doped SnO2 depict improved ability of photodegradation and the optimal ability of SnO2 nanoparticles was achieved at 0.5% Ce doping.

To understand the improved stability and reduced thermal conductivity of 20% CeO2 stabilized ZrO2 coatings compared to pure zirconia, different Ce doped ZrO2 systems are modeled. The Ce insertion in ZrO2 lattice elongates the lattice parameters and the elongation is proportional to the Ce doping concentration. Moreover, the cell volume linearly increases with the Ce doping level. X-ray diffraction analysis confirmed the Zr0.84Ce0.16O2 phase, describing the substitutional Ce doped at Zr sites. Ce doping modified the electronic band structure of ZrO2 without creating any isolated states in the band gap. The Ce4Zr12O32 modeled system with Ce doping concentration of 8.33% provided the stable phonon density of states curves compared to the pure and doped systems. Ce doping reduced the thermal conductivity of ZrO2. Increasing Ce doping level further reduced the thermal conductivity reaching the maximum reduction at 8.33% doping concentration. Further increase in the Ce level has no effective reduction in the thermal conductivity values. The reduced thermal conductivity is attributed to the enhanced phonon scattering due to the substitutional Ce4+ dopant and optimal doping concentration. The experimental observation could be satisfactorily explained by the calculations results.

White light-emitting diodes (LEDs) for green lighting are new solutions for energy saving and environmental protection. Ca3 SiO4 Cl2 :Ce,Eu is an efficient phosphor for white LEDs. Effective energy transfer from Ce(3+) to Eu(2+) occurs in Ca3 SiO4 Cl2 :Ce,Eu due to good spectrum overlap between the emission band of Ca3 SiO4 Cl2 :Ce and the excitation band of Ca3 SiO4 Cl2 :Eu, and hues vary systematically from blue to green at different Ce concentrations. A great improvement in the luminescent property of Ca3 SiO4 Cl2 :Eu has been observed on Ce(3+) doping, which is attributed to energy transfer from Ce(3+) to Eu(2+) and an increase in the number of luminescent centers (Eu(2+) ) on Ce doping. The optimal sample has a quantum efficiency of up to 75%, and can be an efficient green phosphor for white LEDs.

Effect of Ce-doping on microstructure and electrical properties of LaAlO3 ceramics

One-dimensional (1-D) nano-channeled structure has attracted attention as electrode design for the high performance electrochemical devices. This is mainly because its 1-D nano porous structure would allow for the fast ionic transport through it and rapid interfacial reactions. One of the conventional preparation methods of 1-D nano-channeled structure is anodic oxidation. Since the first introduction of anodic aluminum oxide (AAO), different anodic metal oxides with 1-D structure have been reported for the past few decades.Among the various 1-D metallic oxides reported in the literature, tin oxide might be utilized for various applications, such as catalysis, gas sensing, and electrochemical energy storage. In particular, when the nano-channeled tin oxide is used as the anode of the lithium battery, both of the lithia(Li2O) network and nano-channeled structure accommodate the volume change of the tin-lithium phase during the charging/discharging cycles. Although there are some attempts to use the anodic tin oxide thin film as the electrode material for lithium battery, the active material on the substrate was not pure tin oxide but tin - tin oxide bilayer. Since the tin layer underneath anodic tin oxide undergoes a significant reaction-induced volume change, 1-D structure of bilayer collapses during the cycling,In this work, pure anodic tin oxide with well-defined 1-D structure was prepared for the use as the anode for rechargeable lithium battery. Anodic tin oxides with different pore sizes and wall thicknesses were fabricated under various anodizing conditions and their electrochemical properties were characterized by cyclic voltammetry and charge-discharge experiment.In this presentation, cycling stability and rate capability of anodic tin oxides with different porous structures will be presented. Moreover, the feasibility of creating 1-D tin-based anodic oxide composite will be discussed for the further improvement of cycling stability.

Preparation and characterization of Ce doped ZnO nanomaterial for photocatalytic and biological applications

Cerium‐doped yttrium aluminum garnets (Y 3‐ x Ce x Al 5 O 12 , Ce:YAGs) are promising yellow light‐emitting components of solid‐state white light‐emitting diodes. Although there have been numerous studies examining the effects of Ce concentrations on the luminescent properties of Y 3‐ x Ce x Al 5 O 12, the impacts of Ce dopant on the elastic and thermodynamic properties are not well understood. In this work, we used resonant ultrasound spectroscopy (RUS) to determine the effects of Ce doping (0.025, 0.1, 1 at. %) on the elastic and thermodynamic properties of Y 3‐ x Ce x Al 5 O 12 . The elastic moduli calculated via the Voigt–Reuss–Hill (VRH) method demonstrated that low Ce dopant concentrations (≤0.1 at. %) induced negligible effects on the elasticity of the YAG host matrix, while a high Ce concentration (1 at. %) yielded significant softening. RUS spectral analysis and SEM images suggested that the elastic softening originated from microstructural differences induced at higher Ce dopant concentrations. In addition, we demonstrated an increase in elastic anisotropy at higher Ce concentrations, which further elucidated the correlations between structure and elasticity of Y 3‐ x Ce x Al 5 O 12 . Debye temperatures ( θ D ), heat capacities ( C p ), and thermal conductivities ( κ ) were calculated for Ce:YAGs through the relations of RUS‐derived parameters (sound velocities, elastic moduli) and previously determined thermal expansion coefficients. Ce:YAG was found to have a significant reduction in θ D , C p , and κ at Ce concentrations ≥1 at. %. Lastly, extrapolation of C p and κ to higher temperatures allowed the modeling of thermal stress experienced by Y 3‐ x Ce x Al 5 O 12 disks up to 1073.15 K.

Y2Zr2O7 (YZO) is widely used as a host material for luminescent centers because of its high stability and the ability to accommodate anion defects. In this work, the effects of Ce and Tb doping on the photoluminescence (PL) properties of YZO nanoparticles (NPs) are studied in detail to correlate the emission intensity with the dopant concentration. Herein, a two-step synthesis method of coprecipitation and molten salt was employed to prepare the YZO:Tb,Ce NPs. The single doped YZO:Tb (2 mol %) NPs shows a strong Tb3+ emission. However, after codoping with Ce ions, the Tb3+ emission is quenched instead of the expected sensitization. To identify the mechanism of quenching (oxidation state/local symmetry), X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) were performed. The Ce4+ ions were observed to drive further oxidation of Tb to a nonluminescent +4 oxidation state. Alternatively, Eu3+ was employed to probe local symmetry changes upon Ce doping. The asymmetry ratio of the magnetic and electronic transitions indicates that the Ce dopant also pushes the system into a higher symmetry, resulting in two separate quenching mechanisms.

Microwave irradiation method was adopted to synthesize Ce doped CdO nanoparticles. The n-CeCdO/p-Si junction diode was fabricated and it’s parameters have been studied at different doping concentrations (0, 5, 10, and 15 wt%) of Ce. The Ce doping effect was analyzed by various characterization techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray photo electron spectroscopy (XPS), ultra violet–visible spectroscopy (UV–Vis) and DC conductivity (I–V) studies. From XRD analysis, the Ce–CdO nanoparticles depicted a crystalline nature and showed the cubic phase. The crystallite size of the samples varied from 18.72 to 14.68 nm. TEM images reveal that the Ce–CdO nanoparticles have nail-like structure. The presence of the elements Ce, Cd and O were confirmed by EDX and XPS studies. The optical bandgap value decreases with the increasing doping concentration and the minimum band gap energy of 2.70 eV is obtained for 15 wt% Ce–CdO sample. I–V curve represents the semiconducting behavior of Ce–CdO nanoparticles. Variation of current in Ce doped CdO nanoparticles exhibits linear response to applied voltage. The diode behavior was studied under darkness and illumination environment. The major diode parameters, ideality factor and barrier height of n-CeCdO/p-Si junction diode were examined using J–V method.

Quantum chemistry study of SCR-NH3 nitric oxide reduction on Ce-doped γFe2O3 catalyst surface

Structural/compositional characteristics at the anode/electrolyte interface are of paramount importance for the practical performance of lithium ion batteries, including cyclic stability, rate capacity, and operational safety. The anode‐electrolyte interface with traditional separator technology is featured with inevitable phase discontinuity and fails to support the stable operation of lithium ion batteries based on large‐capacity anodes with structural change in charges/discharges, such as transition metal oxide anodes. In this work, an anode/electrolyte framework based on an oxide anode and an active‐oxide‐incorporated separator is proposed for the first time and investigated for lithium ion batteries. The architecture builds a robust anode‐separator interface in LIBs, shortens Li+ diffusion path, accelerates electron transport, and mitigates the volume change of the oxide anode in electrochemical reactions. Remarkably, 4 wt% CuO addition in the separator leads to a 17% enhancement in the overall capacity of a battery with a CuO anode. The battery delivers an unparalleled record reversible capacity of 637.2 mAh g−1 with a 99% capacity retention after 100 charge/discharge cycles at 0.5 C. The high performance are attributed to the robust anode‐separator interface, which gives rise to enhanced interaction between the oxide anode and the same‐oxide‐incorporated composite in the separator.

This paper includes the contribution of cerium (Ce) dopant in enhancing the UV-shielding capacity of nanostructured zinc oxide (ZnO) thin films. Nanoparticles synthesized through the sol–gel process were utilized to create thin films on glass substrates, employing the spin-coating technique for deposition and Ce concentration was adjusted within the range of 1 to 10 mol%. All nanostructures were identified through X-ray diffraction measurements as having a hexagonal wurtzite structure, predominantly oriented along the (002) plane. Scanning electron microscopy revealed uniformly distributed nano-grains and pores throughout the film surface, while energy-dispersive X-ray spectroscopy verified the zinc, cerium, and oxygen contents of the nanostructures and their stoichiometric composition. UV–Visible spectroscopy showed that Ce-doped ZnO (CZO) nanostructures had over 85% transmittance within the visible spectrum. The optical band gap exhibited a declining trend with increasing Ce concentration in ZnO, reaching a minimum value of 3.16 eV at 10-mol% Ce doping. Optical analysis revealed that ZnO doped with 5-mol% Ce (5.15%) in the UVA region and ZnO doped with 4-mol% Ce (19.79%) in the UVB region had higher shielding capacity than undoped ZnO. A comparative evaluation of UV-shielding ratios indicated that 4-mol% Ce doping was optimal in this study, offering superior shielding in both UVB and combined UVA/UVB regions. This study suggests that CZO nanostructures hold significant promise for applications requiring effective UV shielding and enhanced optical performance.

The switching characteristics of rare element Ce-doped HfOx films were investigated. The effect of Ce doping on oxygen defects was analyzed by X-ray photoelectron spectroscopy (XPS) and first-principle calculations. The variations of valence state of Ce and oxygen vacancies with the increase of Ce doping concentration were demonstrated. Although Ce doping increased dopants-induced oxygen vacancies in HfOx film, the density of oxygen vacancies decreased as the doping concentration increased. Besides, the introduction of Ce dopants enlarged the difference in electronegativity of Hf and O which made it harder for O to escape from HfOx film under voltage. Hence the switching behaviors of Ce-doped HfOx film were affected by multiple factors and can be effectively improved with an appropriate doping concentration (4.3%). A physical model based on the formation and rupture of conductive filaments was proposed to clarify the switching behavior of Ce-doped HfOx samples.

An 8-layer depth of interaction (DOI) detector was designed based on the technique we have developed for 4-layer DOI detectors. The new detector achieves 8-layer DOI encoding by pulse shape discrimination (2-layer DOI encoding) and an optimized reflector arrangement in a 3-dimensional crystal array (4-layer DOI encoding). Its capability was proved with an 8-layer 10times10 Gd <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> (GSO) crystal array coupled to a 256-channel flat panel position sensitive photomultiplier tube (256ch FP-PMT). The dimensions of each crystal element were 2.90 mmtimes2.90 mmtimes3.75 mm and the interval between 16times16 multi anodes in the 256ch FP-PMT was 3.04 mm. Two different dopant concentrations in GSO were chosen for pulse shape discrimination: GSO crystals of 0.5 mol% and 1.5 mol% Ce dopant that have 60 ns and 35 ns scintillation decay times, respectively. In the crystal array, Layer-1, the farthest from the 256ch FP-PMT, and Layers-3, -5 and -7 were composed of GSO crystals of 0.5 mol% Ce dopant. All other layers were composed of GSO crystals of 1.5 mol% Ce dopant. Performance of the 8-layer DOI detector was evaluated by irradiating with 662 keV uniform gamma-rays and the capability was judged to be good. To prove the validity of the layer encoding, a fan-beam of 662 keV gamma-rays was irradiated onto the side face of each layer. The obtained 2-dimensional position histograms showed the right structure in each corresponding layer clearly. Light output uniformity among DOI layers and energy resolutions were measured on the pulse height distributions of the central crystal in each layer. The crystals in Layer-2 and Layer-3 showed the smallest light output and their full energy peak channels were 62% to the largest peak channel of the Layer-8 crystal distribution. Energy resolutions were about 15% for all eight layers