- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Preparation of Cerium Oxide Nanoparticles in Salvia Macrosiphon Boiss seeds Extract and Investigation of Their Photo-catalytic Activities
摘要： Cerium oxide nanoparticles (CNPs) with desired particle size and spherical morphology were prepared from cerium nitrate in bio media of Salvia macrosiphon Boiss seeds extract, as a green synthesis route. Then they were characterized by XRD, UV-Vis and FTIR spectroscopies, FESEM and TGA. Band gap energy of the prepared powders was also determined which was found in the range of 2.5 to 3.5 eV. Determination of DLS and zeta potential were showed that CNPs had small size and unique colloidal stability, respectively. Then the photo-catalytic activity of them was investigated by degradation of Rhodamine B (RhB) dye as a model of waste water pollutants, under UV-irradiation and optimum conditions were evaluated. Results showed that decreasing the particle size increased the rate of photo-catalytic reaction remarkably but ascending the band gap energy, in contrast. The photo-catalytic mechanism was also studied by using different scavengers.
关键词： Rhodamine B,Cerium Oxide nanoparticles,Dye,Green synthesis,Photo-degradation,Salvia seeds extract
更新于2025-09-10 09:29:36
-
Surface engineering of polystyrene–cerium oxide nanocomposite thin films for refractive index enhancement
摘要： Polymer nanocomposites have gained much importance in the field of optoelectronics due to their unique optical properties. Refractive index engineering using nanoparticles is an effective strategy that could be applied for the fabrication of optical devices. Herein, we report three different strategies which are employed to enhance the refractive index of polymer thin films. These include incorporating cerium oxide nanoparticles onto the polystyrene matrix, secondly adding cerium oxide nanoparticles onto the cross-linkable polystyrene and thirdly by embedding functionalized cerium oxide nanoparticles onto the cross-linkable polystyrene. Refractive index of the polystyrene thin films was enhanced by dispersing neat CeO2 nanoparticles and functionalized CeO2 nanoparticles into the polystyrene matrix. 1.38% enhancement in the refractive index of the polymer nanocomposite thin films could be achieved using our technique. The blending of polystyrene with cerium oxide nanoparticle presents a prospective way to engineer the refractive index of polymer thin films. We firmly believe that the study will be an effective guide towards future research in the area of surface engineering of polymer thin films for refractive index enhancement.
关键词： Refractive index,Polystyrene,Polymer nanocomposites,Thin films,Cerium oxide,Surface engineering
更新于2025-09-09 09:28:46
-
N-S Codoped Cerium-Cobalt Oxide Bimetal Nanoparticles Catalyzed Photodegradation of Brilliant Green and Fast Green
摘要： Cerium-cobalt oxide bimetal nanoparticles were synthesized using wet precipitation method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photocatalyzed degradation of brilliant green and fast green dyes were studied using CeCoO3 bimetallic nanoparticles spectrophotometrically. Photocatalytic activity has been tested in the reaction of these dyes under visible irradiation. It was revealed that doping enhanced the photocatalytic activity at low doping levels but reduced the activity at high doping levels. Various parameters like amount of semiconductor, pH, light intensity, dye concentration, % of dopant were also studied. The rate of reaction followed pseudo-first order kinetics.
关键词： Nanoparticles,Fast green,Brilliant green,Cerium-Cobalt oxide,Photodegradation
更新于2025-09-09 09:28:46
-
Luminescence and energy transfer studies of Ce3+/Dy3+ doped fluorophosphate glasses
摘要： The fluorophosphate (PKABfNf:P2O5+K2O+Al2O3+BaF2+NaF2) glasses doped with single and co-doped (Ce and/or Dy) were prepared by conventional melt quenching technique and characterized their luminescence properties. The emission spectra of co-doped glass (PKABfNfCeDy) showed a broad blue band of Ce3+ ions combined with the sharp peaks of Dy3+ ions. Judd-Ofelt (JO) intensity parameters have been obtained from the optical absorption spectra of 1.0 mol % of Dy3+ (PKABfNfDy1.0) glass. JO theory has been used to find the radiative properties of PKABfNfDy1.0 glass by using Futchbauer-Ladenbergh formula. The (Ce3+/Dy3+) co-doped glass exhibit radiative energy transfer (ET) from Ce3+ to Dy3+ upon UV excitation and then intensity is increased with increase in Dy3+ ion concentration. The ET mechanism from Ce3+ to Dy3+ ion has been analyzed. The theoretical ET efficiency and quantum yield values were calculated from the emission spectrum of the Ce3+ and (Ce3+/Dy3+) co-doped glasses. These results suggest that the co-doped PKABfNfCeDy glasses are promising candidate for commercial white light applications.
关键词： W-LEDs,Dysprosium,Fluorophosphate glasses,Energy transfer,Judd-Ofelt analysis,Quantum yield,Cerium
更新于2025-09-09 09:28:46
-
Ionic Radii and Concentration Dependency of RE <sup>3+</sup> (Eu <sup>3+</sup> , Nd <sup>3+</sup> , Pr <sup>3+</sup> and La <sup>3+</sup> ) Doped Cerium Oxide Nanoparticles for Enhanced Multi-Enzyme Mimetic and Hydroxyl Radical Scavenging Activity
摘要： The anti-oxidant activity of cerium oxide nanoparticles (CNPs) depends on the concentration of oxygen vacancies and Ce3+ active sites. In the present work, we report the impact of 5 mol% tri-valent rare earth doped (RE3+ = Eu3+, Nd3+, Pr3+ and La3+) CNPs on the oxidation state modulation and anti-oxidant property with respect to ionic radii. An increase in lattice parameter, strain and oxygen vacancy concentration was observed as a function of ionic radii. Among the various dopants in CNP, La3+ with higher ionic radii having smaller crystallite size (7.9 nm) and higher vacancy displayed better peroxidase, oxidase and hydroxyl radical (HO?) scavenging activity. The kinetic parameters for the peroxidase and oxidase activity was found to be superior with Km = 0.217 mM and 0.261 mM, respectively, for 5 mol% La3+ doped CNPs. In order to divulge the role of dopants concentration on structural properties, we also explored using 10 and 20 mol% La3+ doping in CNP. Due to smaller crystallite size (6.7 nm) and higher defect level (3.12 x 1021 cm-3), 20% La3+ doping showed superior peroxidase and oxidase activity as shown by the low Km values. CNPs exhibit both peroxidase and oxidase activity in a concentration dependent manner. Moreover, CNPs exhibit a concentration dependent peroxidase and oxidase activity that can be selectively activated for various theranostic applications. Thus, our results demonstrate the crucial role of ionic radii and concentration of RE3+ dopants on the defect formation in cerium oxide nanoparticles for improved anti-oxidant properties of ceria.
关键词： ionic radii,RE3+ doping,oxygen vacancies,peroxidase activity,oxidase activity,hydroxyl radical scavenging,cerium oxide nanoparticles,anti-oxidant properties
更新于2025-09-04 15:30:14
-
Structural and optoelectronic properties of Ce-Al2O3 nanoparticles prepared by sol-gel precursors
摘要： Pure and Ce-doped Al2O3 nanoparticles (NPs) were synthesized in different cerium percentages of 1%, 2%, and 3% by cerium chloride and aluminum nitrate precursors in the presence of powerful reducing agent-NaBH4 and CTAB stabilizers using sol-gel method. To examine the crystal, morphological, optical, and electronic properties, the XRD, FESEM, TEM, FTIR, UV-DRS, and PL analyses were used for the heated samples in 1000 °C for 4 hours. The XRD analysis indicated that the pure sample has γ, δ and θ phases, and the structure remained unchanged when Ce impurity was increased. The EDS analysis showed that the percentage of Al element was 47.40 wt% in the pure sample and that it increased to 53.83 wt% for 1% doped sample increasing Al ions in tetrahedral and octahedral sites of alumina through increasing Ce impurities. The TEM results revealed the sphere-like particles with mean particle size of 26 nm in diameter at a 3% level of impurity. The FTIR result showed that an increase in AlO4 adsorption peak in 821 cm-1 compared to AlO6 adsorption peak in 619 cm-1 was due to the dominance of vibrating bonds of tetrahedral sites rather than octahedral sites in alumina. The optical UV-DRS analysis also demonstrated the redshift configuration in a sample by increasing Ce dopant and reducing energy bandgap from 4.10 to 3.26 eV for pure and 3% Ce-doped Al2O3 NPs, respectively. Finally, the photoluminescence (PL) results indicated that increasing Ce dopant reduced electron-hole recombination leading to an increase in photocatalytic activity.
关键词： Chemical Synthesis,Cerium dopant,Sol-gel,Ceramics,Al2O3 NPs
更新于2025-09-04 15:30:14
-
Oxygen and cerium defects mediated changes in structural, optical and photoluminescence properties of Ni substituted CeO2
摘要： Local and long-range structural properties, of sol-gel synthesized, Ce1-xNixO2 (0 ≤ x ≤ 0.1) nanopowders have been investigated. Substitution of Ce4+ by comparably smaller Ni2+/Ni3+ ions leads to decrement in lattice parameters. UV-visible spectra reveal decrease of bandgap with increase of disorder upon increasing Ni substitution. The photoluminescence (PL) spectra reveal five major peaks attributed to various defect states. Ni substitution results in the creation of oxygen vacancies (VO) which further leads to conversion of considerable amount of Ce4+ ions to larger size Ce3+. These changes notably, modify the structure of the host lattice. The defects created along with the structural modifications bring, changes in the PL emission. The disorder in the lattice results in increase of non-radiative decay which reduces the PL emission. An increasing VO and Ce3+ concentration at the surface acts as emission quenching centers. Lattice disorder and VO quantities were estimated using X-ray absorption (XAS), UV-vis and Raman spectroscopy.
关键词： Nanoparticles,Urbach energy,Cerium oxide,Strain,Bandgap
更新于2025-09-04 15:30:14
-
Effect of Ce and Mn co-doping on photocatalytic performance of sol-gel TiO2
摘要： Co-doped titanium dioxide was synthesized by doping with manganese (Mn) and cerium (Ce) through a sol-gel method for the degradation of diclofenac (DCF). The synthesized products were successfully characterized by X-ray diffraction (XRD), Raman spectroscopy, Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Nitrogen physisorption at 77 K, X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance (UV-DRS), photoluminescence spectroscopy (PL) and total organic carbon (TOC). It was shown that co-doping increased the specific surface area, improved the visible light absorption and extended the lifetime of photogenerated charge carriers. Furthermore, the results of the photocatalytic experiments show that the photodegradation rate of diclofenac can be approached by pseudo first-order kinetics and it followed the Langmuir-Hinshelwood model very well. The co-doped catalyst with 0.6 % Mn and 1 % Ce molar ratios appeared to be the most photoactive catalyst with 94 % of DCF removal and an apparent rate constant of 0.012 min-1.
关键词： Photocatalysis,co-doping,manganese and cerium,titanium dioxide,diclofenac
更新于2025-09-04 15:30:14