Lanthanum molybdate nanoparticles from the Bradley reaction: factors influencing their composition, structure, and functional characteristics as potential matrixes for luminescent phosphors

Synthesis and characterization of Lanthanum Oxide nanoparticles using Citrus aurantium and their effects on Citrus limon Germination and Callogenesis

The plant extract-mediated method is eco-friendly, simple, safe, and low-cost, using biomolecules as a reducing agent to separate nanoparticles. Lanthanum (La) is a rare earth metal that positively affects plant growth and agriculture. Citrus limon is a leading citrus fruit with many varieties. Conventional vegetative propagation methods depend on season, availability of plant material and are time-consuming. It is the main reason for limiting the acceptance of new varieties. So, In-vitro propagation of the lemon method is practiced overcoming all these problems. Lanthanum oxide nanoparticles (La2O3-NPs) were synthesized using plant extract of C. aurantium. Ultraviolet (UV)-Visible Spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR) spectroscopy, and Thermal Gravimetric Analysis (TGA) were used to characterize the synthesized La2O3-NPs. Fabricated La2O3-NPs were oval and spherical, with an average size of 51.1 nm. UV-visible absorption spectra of La2O3-NPs were shown at a sharp single peak at 342 nm and FTIR showed stretching frequency at 455 cm-1-516 cm-1. In the TGA outcome, mass loss was 9.1%. In vitro experiments demonstrated that La2O3-NPs significantly enhanced the germination and growth of C. limon seeds, achieving an 83% germination rate at 5 mg/L concentration, with uncoated seeds showing root initiation at 10 days and shoot formation at 15 days. Furthermore, La2O3-NPs effectively stimulated callus induction and maturation, with optimal responses observed in media containing MS and 2 mg/L 2,4-D, resulting in a maximum callus frequency of 100% from leaves and 87.5% from shoots at 5 mg/L concentration. These findings underscore the potential of La2O3-NPs to improve seed germination rates, seedling vigor, and callogenesis efficiency, suggesting their promising integration into agricultural practices for sustainable crop production, especially in suboptimal growing conditions. Future research is recommended to explore the mechanisms and broader applications of La2O3-NPs across various plant species and environments.

Comparative and Efficient Ammonia Gas Sensing Study with Self-assembly-Synthesized Metal Oxide-SiC Fiber-Based Mesoporous SiO2 Composites

Self-assembled-assisted ternary nanocomposite In₂O₃-SiC, CuO₂-SiC, and MnO₂-SiC semiconductors were mixed with SiO₂ to enable gas sensing using cyclic voltammetry. The results of TEM (transm In₂O₃-SiC-SiO₂ ion electron microscopy), X-ray diffraction spectroscopy, and Raman spectra analysis affirm the closeness of few layers between SiO₂ and SiC in In₂O₃-SiC, MnO₂-SiC, and CuO₂-SiC. Among the electrochemical impedance spectra curves of the nanocomposites, none of the samples had a semicircle profile, which indicates the existence of a higher charge-transfer resistivity behavior between the electrolyte and the sample electrode with charge carrier and transport effects, which is related to the well-developed porous structure of synthesized composites. CuO₂-SiC-SiO₂ and MnO₂-SiC-SiO₂ showed high resistivity and a quite significant response for NH₃ gas at room temperature. While there was a response for NH₃ gas for In₂O₃-SiC-SiO₂, the sensor showed a low response for the gas. From the sensing test, correspondences between the chemical structure of the sensor and the molecular structure of the gases have been found. The surface reactions between the sensor surface and the gas with a pore structure, along with the electron receiver/donor phase are observed from the results of gas sensor tests, and all factors are determining the precise state. Finally, the adsorption of NH₃ molecules and the alteration of the electronic resistance of In₂O₃-SiC-SiO₂, MnO₂-SiC-SiO₂, and CuO₂-SiC-SiO₂ were presented that include various thicknesses of charge to represent which are achieved by the connection with the substrates and the particles.

Exploring color tunable emission characteristics of Eu3+-doped La2(MoO4)3 phosphors in the glass-ceramic form

The glass–ceramic form of phosphor materials can overcome the many serious issues of phosphor/silicone composite in commercial phosphor-converted LEDs and are considered as new-generation color converters. In this report, we have shown a novel approach of developing inorganic red phosphor [Eu³⁺:La₂(MoO₄)₃] in the glass–ceramic form based on lanthanum molybdate system. The ceramic form of the compound was found to have a glass transition temperature of 1002 °C, as confirmed by TGA and DSC studies. Further, XRD, FTIR and Raman studies also confirmed that the compounds prepared at 1050 °C are in glass–ceramic form, while those prepared at 750 °C are in ceramic form. Photoluminescence studies showed that both the ceramic and glass–ceramic forms of the phosphor are red color-emitting materials. However, the glass–ceramic forms have better color purity and more radiation transition probabilities. Further, the decay kinetics of both ceramic and glass–ceramic forms confirmed that only those Eu³⁺ ions which exist in the grain boundaries of the ceramics go inside the glass network structure upon heating the compound at or above the glass transition temperature. On the other hand, Eu³⁺ ions which exist at the La-site in the bulk of the particles are retained in the ceramic form in the glass–ceramic mixture.

The glass–ceramic Eu-LMO-1050 is more suitable as a red-color-emitting phosphor material than the ceramic Eu-LMO-750. Further, Eu-LMO-1050 can overcome the problems related to the phosphor/silicone composite in commercial LEDs.

Single-Source Alkoxide Precursor Approach to Titanium Molybdate, TiMoO5, and Its Structure, Electrochemical Properties, and Potential as an Anode Material for Alkali Metal Ion Batteries

Transition-metal oxide nanostructured materials are potentially attractive alternatives as anodes for Li ion batteries and as photocatalysts. Combining the structural and thermal stability of titanium oxides with the relatively high oxidation potential and charge capacity of molybdenum(VI) oxides was the motivation for a search for approaches to mixed oxides of these two metals. Challenges in traditional synthetic methods for such materials made development of a soft chemistry single-source precursor pathway our priority. A series of bimetallic Ti-Mo alkoxides were produced by reactions of homometallic species in a 1:1 ratio. Thermal solution reduction with subsequent reoxidation by dry air offered in minor yields Ti₂Mo₂O₄(OMe)₆(OⁱPr)₆ (1) by the interaction of Ti(OⁱPr)₄ with MoO(OMe)₄ and Ti₆Mo₆O₂₂(OⁱPr)₁₆(iPrOH)₂ (2) by the reaction of Ti(OⁱPr)₄ with MoO(OⁱPr)₄. An attempt to improve the yield of 2 by microhydrolysis, using the addition of stoichiometric amounts of water, resulted in the formation with high yield of a different complex, Mo₇Ti_7+xO_31+x(OⁱPr)_8+2x (3). Controlled thermal decomposition of 1–3 in air resulted in their transformation into the phase TiMoO₅ (4) with an orthorhombic structure in space group Pnma, as determined by a Rietveld refinement. The electrochemical characteristics of 4 and its chemical transformation on Li insertion were investigated, showing its potential as a promising anode material for Li ion batteries for the first time. A lower charge capacity and lower stability were observed for its application as an anode for a Na ion battery.

Controlled decomposition of a structurally characterized Ti-Mo oxo-alkoxide precursor offered an approach to the new ternary oxide TiMoO₅, showing promising characteristics as an anode material for Li ion batteries.

Scandium Molybdate Microstructures with Tunable Phase and Morphology: Microwave Synthesis, Theoretical Calculations, and Photoluminescence Properties

In this paper, scandium molybdate microstructures have been prepared from solution via a microwave heating method. By controlling the experimental parameters such as molar ratio of reagent and reaction time, scandium molybdates with tunable phase and diverse morphologies including snowflakes, microflowers, microsheets, and branched spindles were obtained. The density of states and surface energies of Sc₂Mo₃O₁₂ were primarily studied from first-principles calculations. An indirect band gap of 3.56 eV was observed for crystalline Sc₂Mo₃O₁₂, and the surface energies of various facets were determined to be 0.27-0.91 J/m². The influence of n(Sc³⁺): n(Mo₇O₂₄^6-) (short for Sc/Mo) molar ratio was systematically investigated and well-characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and UV-vis absorption spectroscopy (UV-vis). Results indicate that the Sc/Mo molar ratio has a great effect on the phase and morphology. Diffuse reflection spectra (DRS) revealed the E_gap can be readily tuned from 3.69 to 4.16 eV, which is in accordance with the theoretical result. The photoluminescence (PL) properties of Eu³⁺-doped Sc₂Mo₃O₁₂ were discussed. This facile synthesis strategy could be extended to the synthesis of other molybdates.

Non-contact Mn1−xNixFe2O4 ferrite nano-heaters for biological applications – heat energy generated by NIR irradiation

Effective heat generation achieved on Mn_1−xNi_xFe₂O₄ferrite nano-heaters using NIR light irradiation instead of AC magnetic field.

Multifunctional lanthanide and silver ion co-doped nano-chlorapatites with combined spectroscopic and antimicrobial properties

Nanocrystalline chlorapatites (Ca10(PO4)6Cl2) doped with lanthanide ions (Eu(3+), Er(3+) and Yb(3+)) and co-doped with silver ions (Ag(+)) were synthesized by a hydrothermal synthesis route. XRD, TEM, and SAED measurements indicated that the powders are single phased and crystallize with a hexagonal structure with good dispersion. The results showed well crystallized chlorapatite grains with a diameter of about 45 nm. The antimicrobial activity of the nanoparticles against Escherichia coli ATCC 11229 and ATCC 25922, Klebsiella pneumoniae ATCC 700603, and Pseudomonas aeruginosa PAO1 and ATCC 27853 was studied. The best activity was observed for the Eu(3+),Ag(+):Ca10(PO4)6Cl2 and Eu(3+),Ag(+),Yb(3+):Ca10(PO4)6Cl2 compositions. These multifunctional nanocrystalline powders could be used as a promising antimicrobial agent and material for bio-detection.

Sodium citrate (Na3Cit)-assisted hydrothermal synthesis and characterization of twinned hemisphere shaped La2(MoO4)3:Eu3+ phosphors

Sodium citrate (Na₃Cit) mediated hydrothermal synthesis and characterization of twinned hemisphere shaped La₂(MoO₄)₃:Eu³⁺ phosphors.

New insight into rare-earth doped gadolinium molybdate nanophosphor assisted broad spectral converters from UV to NIR for silicon solar cells

Demonstration of novel rare-earth doped gadolinium molybdate nanophosphor assisted broad spectral converters from UV to NIR for Si-solar cell application.