Zero-Dimensional Graphene and Its Behavior under Mechanochemical Activation with Zinc Ferrite Nanoparticles
- PDF / 1,568,036 Bytes
- 7 Pages / 432 x 648 pts Page_size
- 38 Downloads / 149 Views
MRS Advances © 2019 Materials Research Society DOI: 10.1557/adv.2019.400
Zero-Dimensional Graphene and Its Behavior under Mechanochemical Activation with Zinc Ferrite Nanoparticles Monica Sorescu1, Matthew Knauss1, Alice Perrin2 and Michael McHenry2 1
Duquesne University, Department of Physics, Fisher Hall, Pittsburgh, PA 15282
2 Carnegie Mellon University, Department of Materials Science and Engineering, Roberts Hall, Pittsburgh, PA 15213
ABSTRACT
Equimolar mixtures of zero-dimensional graphene (SkySpring Nanomaterials, 1-5 nm particle size) and zinc ferrite nanoparticles (Alfa Aesar, 50 nm particle size) were exposed to mechanochemical activation by high-energy ball milling for time intervals of 0-12 hours. Their structural and magnetic properties were analyzed by Mӧssbauer spectroscopy and magnetic measurements. The spectra of zinc ferrite milled without graphene were fitted with one quadrupole-split doublet (quadrupole splitting 0.5 mm/s, isomer shift 0.23 mm/s) and indicated that zinc ferrite was superparamagnetic. The line width of the doublet increased from 0.41 to 0.64 mm/s, which correlates with a reduction in particle size as effect of the ball milling processing performed. When graphene was added to the milling powders, the Mӧssbauer spectra showed the appearance of another quadrupole doublet, with a quadrupole splitting of 0.84 mm/s and an isomer shift of -0.38 mm/s. Its abundance to the spectrum remained constant to 4.48% while the milling time was increased. This second doublet could be related to carbon atoms occupying neighborhoods in the proximity of iron atoms. Hysteresis loops were recorded in an applied magnetic field of 5 T at a temperature of 5 K. A change in the approach to saturation of the loop was observed, with saturation being achieved for the sample milled for 12 hours with graphene. Zero-field-cooling-field-cooling (ZFC-FC) was performed on all samples between 5-300 K with an applied magnetic field of 200 Oe. Graphene was found to stabilize the magnetic properties of the milled system of powders to a blocking temperature of about 90 K.
Downloaded from https://www.cambridge.org/core. IP address: 95.85.80.111, on 10 Dec 2019 at 23:37:43, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/adv.2019.400
INTRODUCTION Graphene (also encountered as reduced graphene oxide, rGO) is a twodimensional one-atom-thick carbon material composed of sp2 hybridized carbon atoms, exhibiting excellent electrical, mechanical and thermal properties, which have been widely used in many fields, such as electronics, sensors, batteries and supercapacitors [18]. Both theoretical and experimental studies have demonstrated that the intentional incorporation of heteroatoms into the graphene structure could effectively modify its electronic and chemical properties. On the other hand, the competing incorporation of carbon atoms into the ferrites structure during milling represents the central hypothesis of the present study. If two-dimensional
Data Loading...
