Advanced Materials Research Vol. 938

Abstract: The 1:1 condensation reaction between benzil and tris (hydroxymethyl) aminomethane in methanol yields a hetero bicyclic compound 5-(hydroxymethyl)-1,2-diphenyl-3,7-dioxa-8-aza-bicyclo [3.2.octan-2-ol. It was characterized by FT-IR, NMR (¹H and ¹³C) spectroscopy and ESI mass spectrometry. The structure was conclusively determined by X-ray diffractrometric analysis. The structure shows a hetero bicyclic ring system. It consists of six membered morpholine and five membered oxazolidine rings with free hydroxyl groups. This bicyclic compound was used as a reducing and stabilizing agent to prepare zinc nanoparticles. The morphology and structure were characterized by field emission scanning electron microscope (FE-SEM), powder X-ray diffraction (XRD), and energy dispersive spectrum analysis (EDS).

Abstract: Highly uniform and self-assembled spheroid-like microstructures of Na_0.5La_0.5MoO₄:Eu³⁺ were successfully synthesized by hexamine assisted hydrothermal route at 180 °C for 24 hours with neutral pH (7~8). Scanning electron microscope, X-ray diffraction pattern and energy dispersive X-ray analysis were used to characterize the morphology, crystal structure, size, and elements of the particles. It is found that, the particle size was well-controlled by increasing the molar concentration of the chelating agent hexamine. While, irradiating at 395 nm UV light, the emission spectra of micro-spheres shows remarkable characteristic dominance of red emission which is attributed to the transition ⁵D₀⁷F₂. Furthermore, the synthesized homogeneous and well-crystallized Na_0.5La_0.5MoO₄:Eu³⁺ microstructures will serve as an excellent phosphor candidate to produce high-quality luminescence for display devices in future.Keywords: Hydrothermal route, hexamine, self-assembly, photoluminescence

Abstract: Cobalt ferrite (Cofe₂o₄) particles were synthesized with and without presence of surfactants using a co-precipitation method. Three surfactants Cetyl Tri methyl Ammonium Bromide (CTAB-cationic), Sodium dodecylbenzenesulphonate (anionic), Triton X-100 (nonionic), were used and investigate their effects on the structural and dielectric properties of CoFe₂O₄ particles. The ferrite precursors were first pre calcined in a muffle furnace at 500°C and then calcined at 950^°C. Structural, dielectric and magnetic properties of prepared particles were investigated using X-ray powder diffraction, Dielectric and Low field ac magnetic susceptibility measurement. Phase purity of prepared samples was confirmed by X-ray diffraction. The sample with surfactant Triton X-100 shows the highest values of dielectric constant at low frequency.

Abstract: The production of high purity samarium doped ceria (SDC20, Sm_0.2Ce_0.8O_2-δ) nanopowders by modified sol-gel process using maltose and pectin as organic precursors. Around, 6 nm particle size can be obtained after calcination of the as synthesized (pre dried) gel at 500 °C for 2 h. Rietveld refinement of Powder X-ray diffraction (XRD) patterns confirms the cubic structure with single phase. Chemical composition of SDC20 is in good agreement with EDX measurements. TEM and XRD analysis indicate the influence of sintering temperature on particle size, which increases with increasing temperature. This modified sol-gel process is a non-toxic and environmentally friendly for large-scale production of high purity nanopowders.

Abstract: Z-type hexaferrite with composition Ba₃Co₂Fe₂₄O₄₁ has been synthesized using a sol-gel auto combustion technique. The obtain combusted powder was sintered at 500 OC and followed by 950 OC for 4 hrs in a muffle furnace. The effect of different sintering temperature on crystal structure, crystallite size, microstructure and dielectric properties were systematically investigated. The prepared barium cobalt hexaferrite powder samples were characterized using different experimental techniques like FTIR, XRD, AC conductivity and specific magnetization measurements. It was observed from XRD results that heat treatment conditions play significant role in the formation of hexaferrite phase. AC conductivity measurements were carried out at room temperature in frequency range of 20Hz to 2MHz. All the samples show the frequency dependent phenomena, i.e. the AC conductivity increases with increasing frequency.

Abstract: Silver nanoparticles are synthesized using N,N dimethyl formamide (DMF) both as reductant as well as solvent. The reaction is performed in the presence and absence of surfactants at room temperature to know the effect of the same on the size and shape of the silver nanoparticles. In this regard, two different surfactants viz. polyvinylpyrolidone (PVP) and cetyl trimethyl ammonium bromide (CTAB) are used. The rate of the reaction and the formation kinetics is continuously monitored by UV-vis spectroscopy at regular time intervals. The corresponding change in plasmonic peaks and full width half maxima (FWHM) is studied in detail. The particle size is determined using Mie plot.

Abstract: Carbon based materials have attracted much for its unique surface microstructure and nanomechanical properties among researchers. In this study, the influence of microstructure on the nanomechanical properties of thin carbon based films was studied in detail. For which amorphous Carbon nitride (a-CN) and Titanium incorporated amorphous Carbon nitride (Ti/a-CN) thin films were prepared with a thickness of less than 100 nm using hybrid ion beam deposition technique. The incorporation of Ti into the a-CN matrix greatly modified the sp³/sp² hybridized bonding ratio and it is reflected in the mechanical hardness of Ti/a-CN thin film. Most of the incorporated Ti reacts with carbon and nitrogen to form TiN and TiCN phases respectively. On the other hand, owing to the usage of energetic ion bombardment and the presence of TiN/TiCN phases in the carbon nitride matrix, the Ti/a-CN nanocomposite film shows improved adhesion strength compared to that of pure a-CN film. Overall the presence of hard metallic phase in the amorphous carbon network alters the microstructure and improves the adhesion strength of a-CN films suitable for protective coating applications.

Abstract: We have synthesized metal phthalocyanine modified multiwalled carbon nanotube by a solid-phase synthesis method by heating a reaction mixture of phthalic anhydride, ammonium molybdate and MWCNT in a required molar ratio using muffle furnace. The metal phthalocyanine modified MWCNT samples collected and then washed extensively with various solvents to removal all impurities and unreacted starting materials. The resulting nanocomposite was characterized by IR, UV-Visible spectroscopy, Scanning Electron Microscopy, X-ray diffraction and Raman spectroscopy. The nanostructure of the CuPc/MWCNT assembly exhibits a homogeneous nanocomposite. The electrocatalytic study of the CuPc/MWCNT assembly towards the oxidation of nitrite was investigated. An enhanced oxidation peak current was noted with lowering oxidation over potential ranges. The proposed method can be applied for the amperometry detection of nitrite present in food samples.

Abstract: A series of Ce_xZr_(1-x)O₂ mixed oxides with different ratio (0 x 1) have been synthesized using microemulsion method. The structure and morphology of the mixed oxides have been investigated via X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). The results showed that the synthesized mixed oxides were of nanoscale size and the cubic phase was obtained with the application of a ratio of x > 0.5. Additionally, it was found that the tetragonal phase existed with lower ceria content. The average crystallite size of the Ce_xZr_(1-x)O₂ series were found to be in the 5 - 10 nm range. Moreover, the roughness of these mixed oxides had also decreased with increasing ceria content.