Synthesis, characterization and effect of dopant on magnetic hyperthermic efficacy of Gd2O3 nanoparticles

Rare-earth oxides are paramagnetic materials and their high magnetic susceptibility in the bulk makes them potentially promising materials, but the magnetic properties of their nanoparticles remain incompletely characterized. We explore the effect of dopant (Tb3+ and Eu3+) in Gd2O3 host lattice as a heating agent for magnetic hyperthermia application. The structural, optical, and magnetic properties of the pristine, Gd2O3:Tb3+ and Gd2O3:Eu3+ nanocrystals were studied by XRD, HR-TEM, FTIR, and VSM. XRD analysis revealed the presence of mixed phase (cubic and monoclinic) in pristine, and doped Gd2O3 nanoparticles. The morphological information has been observed with the help of HRTEM and the calculated inter-planar spacing is in well agreement with JCPDS data. Particles are nearly spherical and diameter ~15nm, estimated from HRTEM image. FTIR spectroscopic analysis confirms the presence of Gd-O-Gd stretching at 583cm-1 . We confirmed the paramagnetic nature for all samples using VSM analysis. The self-heating capability of prepared samples are investigated by performing the induction heating experiment and it is assessed through calculated SAR and ILP values with help of Box-Lucas fitting model where 10% Tb3+ doped Gd2O3 has maximum values.

Synthesis of Gd2O3 Nanoparticles and Their Photocatalytic Activity for Degradation of Azo Dyes

Gadolinium oxide (Gd2O3) nanoparticles were prepared via the reaction of gadolinium nitrate hexahydrate (Gd (NO3)3·6H2O) and ethylamine (C2H5NH2), and their surface morphology, particle size, and properties were examined by using scanning electron microscopy, X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and ultraviolet visible (UV-vis) spectroscopy. The Gd2O3 nanoparticles were used as the photocatalyst for the degradation of various azo dyes, such as methyl orange (MO), acid orange 7 (AO7), and acid yellow 23 (AY23) under irradiation with UV light. The effect of the experimental parameters (initial concentration of azo dyes, dosage of catalyst, and wavelength of UV light) on the photocatalytic properties of the Gd2O3 nanoparticles were investigated. At a constant H2O2 concentration, the photocatalytic degradation efficiency of the Gd2O3 nanoparticles for various azo dyes was in the order: methyl orange > acid orange 7 > acid yellow 23. The kinetics study showed that the photocatalytic degradation of azo dyes was followed by a pseudo first-order reaction rate law.