Journal of NanoScience in Advanced Materials

Comparative Study of Photocatalytic Performance of Nanocrystalline Bismuth Ferrite Synthesized by Sol-gel and Hydrothermal Methods

Nurvet Kirkgecit — 2024-06-30

Nanocrystalline Bismuth Ferrite (BiFeO3, BFO) catalyst materials were synthesized using hydrothermal and sol-gel methods in order to examine the impact of crystallite size on photocatalysis. Crystal structures and optical properties were studied to explore photocatalytic performance. X-ray Diffraction analysis (XRD) showed that both synthesized samples were formed in pure BiFeO₃ without any secondary and impurity phases. The average crystallite size values calculated using the Debye-Scherrer formula were calculated as 39 nm and 46 nm for samples prepared by sol gel and hydrothermal methods, respectively. Photocatalytic activities of BFO nanocrstallite materials were studied by using methylene blue dyestuff water solution under a solar simulator. It was noted that the photocatalytic efficiency of BFO nanocrstallite synthesized by the sol gel method was higher compare to that of the synthesized by hydrothermal one. It was indicated that such an increase for the efficiency could be related with the dual effect of decreasing crystallite size and bandgap.

Effect of Nano-Sized Europium Substitution on Strontium Sites on Diamagnetic Properties in BiPb-2223 Superconductor System

Mehmet Ersin AYTEKİN — 2024-06-30

In the current study, different amounts of nano-sized Eu (80 nm) (x = 0.0, 0.20 and 0.25) were substituted to strontium sites in the Bi_1.7Pb_0.3Sr₂Ca₂Cu_2.75Na_0.25O_y system. Ceramic samples produced by the solid state reaction method were analyzed by performing X-ray diffraction measurements (XRD), scanning electron microscope measurements (SEM) and M-H measurements. In the results of X-ray diffraction measurement, it was determined that the main phase structure was Bi-2223 superconductivity phase, although some impurity phases were formed in all samples. In the findings obtained from scanning electron microscopy measurements, it was observed that all samples consisted of flaky plate-like grain structures containing the presence of Bi-2223 phase structure. With the formation of minor impurity phases in the morphological structure, differences in grain behavior have occurred in some regions. M-H measurements were performed to characterize the magnetic properties of the samples. In M-H measurements, diamagnetic behavior, which is characteristic of the Bi-2223 superconductor phase, was observed in sample, nano sized Eu-free.

Structural, Magnetic, Electrical and Dielectric Characterizations of Co0.5Ni0.5FeCuO4 Ferrite

Ahlem Cherif — 2024-06-30

The Co_0.5Ni_0.5FeCuO₄compound was elaborated using sol-gel reaction route. X-ray diffraction patterns indicated that the sample crystallize in the cubic spinel structure (Fd-3m space group). Magnetic measurements revealed that the prepared sample showed a paramagnetic-ferromagnetic transition at T_C= 785K. Then, dielectric data has been carried out by means of impedance spectroscopy in a wide frequency and temperature ranges. For the sample, the activation energy E_a estimated from the slope of the linear fit plot is equal to 0.42 eV at temperature range 200-420 K. The electrical modulus and impedance studies reveal the presence of a relaxation phenomenon with non-Debye type in the prepared sample. Nyquist representation (Z″ vs. Zʹ) was plotted and their characteristic behavior was analyzed in terms of electrical equivalent circuit.

Inkjet Printing of Palladium Decorated-Carbon Nano Onion-based Aqueous Inks

Merve Dilşen — 2024-06-30

Herein, we designed a novel ink formulation with high stability and printability using onion-like carbon nanoparticles (CNO) decorated with sulfonate (-SO₃H) groups and Palladium (Pd) nanoparticles. The modification of hydrophilic -SO₃H groups enabled us to achieve high print quality. We also demonstrated that Pd nanoparticle decoration did not yield a detrimental effect on the printability of the CNOs. The surface tension of Pd-decorated SO₃H/CNO was measured to be 70.3 mN/m and using sodium dodecyl sulfate (SDS) surfactant with 0.5 mg/ml concentration, the printability of the ink enhanced. The stability of the inks was experimentally studied by zeta potential measurements. The printed layers were characterized using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) methods and the results indicated highly homogeneous printed layers. The effect of the printing pass number was evaluated by measuring the print resistance and the lowest resistance was achieved at 65 printing passes.

The Effect of Cr-doped on Structural, Magnetic and Magnetocaloric Properties of La0.8Sr0.15Na0.05Mn(1-x)CrxO3 (x=0.00, 0.15 and x=0.20) Compounds

Nadia Zaidi — 2024-06-30

The physics properties of manganite oxides La_0.8Sr_0.15Na_0.05Mn _(1-x)Cr_xO3 synthesized by solid-solid method were studied in details. X-ray diffraction analyses showed a single rhombohedral phase with R3-c space group. The inhomogeneous magnetic comportment coupled was used to explain the magnetic properties and the evolution of the paramagnetic-ferromagnetic transition of the materials. The maximum values of magnetic entropy change (ΔS_Max) decreased from 5.77 Jkg-1K for La_0.8Sr_0.15Na_0.05MnO₃ to La_0.8Sr_0.15Na_0.05Mn_0.8Cr_0.2O₃ 5.12 Jkg-1K for upon an applied magnetic field of µ_0H=5 T, indicating an excellent quality of our samples as compared to many manganite oxides. The high quality of our samples was also checked by the large relative cooling power (RCP) which provides a good performance for industrial technologies in refrigeration device.