Free and partially encapsulated manganese ferrite nanoparticles in multiwall carbon nanotubes.

Saja Al-Khabouri,Abbsher M Gismelseed,Ahmed D Al-Rawas,Myo Tay Zar Myint,Ashraf Al-Hinai,Salim Al-Harthi,Toru Maekawa,Ali A Yousif,Mohamed E Elzain

doi:10.3762/bjnano.11.170

Abstract

Free and partially encapsulated manganese ferrite (MnFe2O4) nanoparticles are synthesized and characterized regarding structure, surface, and electronic and magnetic properties. The preparation method of partially encapsulated manganese ferrite enables the formation of a hybrid nanoparticle/tube system, which exhibits properties of manganese ferrite nanoparticles inside and attached to the external surface of the tubes. The effect of having manganese ferrite nanoparticles inside the tubes is observed as a shift in the X-ray diffraction peaks and as an increase in stress, hyperfine field, and coercivity when compared to free manganese ferrite nanoparticles. On the other hand, a strong charge transfer from the multiwall carbon nanotubes is attributed to the attachment of manganese ferrite nanoparticles outside the tubes, which is detected by a significant decrease in the σ band emission of the ultraviolet photoemission spectroscopy signal. This is followed by an increase in the density of states at the Fermi level of the attached manganese ferrite nanoparticles in comparison to free manganese ferrite nanoparticles, which leads to an enhancement of the metallic properties.

Highlights

Since the discovery of carbon nanotubes (CNTs), researchers have been interested in functionalizing, inserting, and encapsulating materials inside their inner cavities
It has been suggested that encapsulating materials into the hollow regions of carbon nanotubes can result in a significant change of the properties of the inserted materials [1,2,3]
Carbon nanostructures decorated with titania and silica are used for the removal of harmful pollutants [8], carbon nanotubes decorated with molybdenum disulfide are used in microbial fuel cells [9] and photoelectric detectors [10], supercapacitor electrodes use binary metal oxide/multiwall carbon nanotubes (MWCNTs) [11], among other numerous recently developed applications [12]

Summary

Introduction

Since the discovery of carbon nanotubes (CNTs), researchers have been interested in functionalizing, inserting, and encapsulating materials inside their inner cavities. To fit the measured Mössbauer spectra of free MnFe2O4 nanoparticles, two different subspectra associated with tetrahedral (A) and octahedral (B) sublattices, with close but different hyperfine fields, were used in addition to a superparamagnetic doublet (Figure 1f).

Results

Conclusion