pH- and Dopant-Dependent CdMoO4:Mn Nanocrystals: Luminescence and Magnetic Properties

Synthesis, Optical Properties and Applications of Ternary Oxide Nanoparticles by a Microwave Technique

Nanocrystal preparation is in high demand due to the development of nanodevices. Nanostructures or microstructures of binary oxides such as TiO₂, ZnO, and Al₂O₃ have been extensively prepared and studied. Synthesis of ternary oxide nanomaterials with controlled structures, morphologies, and sizes are of interest due to their potential applications in nanodevices caused by tunable energy level, bandgap, and structure. In this work, a solution-based method is used to prepare CaWO₄ and LaPO₄ ternary oxide nanomaterials by microwave technique. Controlled sizes and morphologies including nanorods and microspheres are synthesized by the microwave method, which is believed to be a facile and low-cost technique for the synthesis of ternary oxide nanomaterials. Furthermore, the (relatively) quick process enables high efficiency of the production. The structural and optical properties of the prepared nanomaterials are also investigated in this work. This work benefits nanomaterial synthesis for nanomanufacturing and applications in lighting and photodynamic activations as well as optical storage.

Plasmonic Ag decorated CdMoO4 as an efficient photocatalyst for solar hydrogen production

The synthesis of Ag-nanoparticle-decorated CdMoO4 and its photocatalytic activity towards hydrogen generation under sunlight has been demonstrated. The CdMoO4 samples were synthesized by a simple hydrothermal approach in which Ag nanoparticles were in situ decorated on the surface of CdMoO4. A morphological study showed that 5 nm spherical Ag nanoparticles were homogeneously distributed on the surface of CdMoO4 particles. The UV/DRS spectra show that the band gap of CdMoO4 was narrowed by the incorporation of a small amount of Ag nanoparticles. The surface plasmonic effect of Ag shows broad absorption in the visible region. The enhanced photocatalytic hydrogen production activities of all the samples were evaluated by using methanol as a sacrificial reagent in water under natural sunlight conditions. The results suggest that the rate of photocatalytic hydrogen production using CdMoO4 can be significantly improved by loading 2% Ag nanoparticles: i.e. 2465 μmol h-1 g-1 for a 15 mg catalyst. The strong excitation of surface plasmon resonance (SPR) absorption by the Ag nanoparticles was found in the Ag-loaded samples. In this system, the role of Ag nanoparticles on the surface of CdMoO4 has been discussed. In particular, the SPR effect is responsible for higher hydrogen evolution under natural sunlight because of broad absorption in the visible region. The current study could provide new insights for designing metal/semiconductor interface systems to harvest solar light for solar fuel generation.

Dielectric and magnetic characteristics of Ca1-x Mn x MoO4 (0 ≤ x ≤ 0.15) nanomaterials

Scheelite-type Ca_1-x Mn _x MoO₄ (x = 0.0, 0.01, 0.05, 0.10 and 0.15) nanomaterials were successfully synthesized via a combustion route. Dielectric studies showed a weak n-type electrical conductivity characteristic for insulators and low relative permittivity (ε _r < 15) decreasing with increasing Mn²⁺ content. CaMoO₄ and Mn²⁺-doped nanomaterials are chemically compatible with Al and Ag electrodes and promising for low-temperature co-fired ceramic applications. Magnetic studies showed, at room-temperature diamagnetism for pure CaMoO₄, the balance between diamagnetism and paramagnetism for Ca_1-x Mn _x MoO₄ (x = 0.01) and paramagnetic behaviour when 0.05 ≤ x ≤ 0.15 as well as the short-range antiferromagnetic interactions growing in strength as Mn²⁺ content increases. The Landé factor fitting procedure showed a spin-only contribution to the magnetic moment. CaMoO₄ matrix unexpectedly revealed the residual paramagnetism at low temperatures derived probably from the molybdenum ions having unpaired 4d electrons as well as a paramagnetic-diamagnetic transition at 70 K.

Synthesis, properties, and formation mechanism of Mn-doped Zn2SiO4 nanowires and associated heterostructures

Charge transfer and energy transfer phenomena were observed and analyzed in heterostructure systems composed of CdSe QDs immobilized onto Mn-doped Zn₂SiO₄ nanowire host materials.

NiMoO4-modified MnO2 hybrid nanostructures on nickel foam: electrochemical performance and supercapacitor applications

A novel electrode of NiMoO₄-modified MnO₂ not only keeps MnO₂ from dissolving in an alkaline electrolyte, but also improves the capacitance.