Optical and electrochemical properties of iron oxide and hydroxide nanofibers synthesized using new template-free hydrothermal method
Date
2020
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Nanostructure in Chemistry
Abstract
We report the effect of hydrothermal synthesis conditions on the morphological, optical and electrochemical properties of
as-prepared iron oxide (γ-Fe2O3) and hydroxide (α-FeOOH) nanostructures. The physico-chemical identification of these Febased
nanostructures using X-ray diffraction, scanning/transmission electron microscopy, porosity and Raman spectroscopy
analyses revealed a temperature-depended phase transformation. A maghemite and goethite iron-based nanostructured formation
was observed in nanorod and trigonal nanofiber shape-like morphology with mean diameters ranging from 32 to 50 nm.
The textural analysis of the nanofibers confirmed mesoporosity with a specific surface area of ~ 129 m2
g−1 (in γ-Fe2O3) and
23 m2
g−1 (in α-FeOOH). The electrochemical performance of the iron oxide and hydroxide nanofiber electrodes with and
without the addition of activated carbon (AC) was also investigated. The sample electrodes composed of γ-Fe2O3, γ-Fe2O3/
AC, α-FeOOH and α-FeOOH/AC showed remarkable specific capacities of 164 mAh g−1, 330 mAh g−1, 51 mAh g−1 and
69 mAh g−1 at 1 A g−1 gravimetric current. The influence of the phase transformation linked to the synthesis temperature,
and the inclusion of an electric double-layer AC material into the nanofibers clearly demonstrates an enhancement in their
energy-storage capability. Furthermore, the Fe-based nanofibers exhibited excellent cycling stability with good capacity
retention of 73% and 99.8%, respectively, after 2000 cycles at a high 30 A g−1 gravimetric current as well as low resistance
obtained by impedance spectroscopy analysis. The implication of the results depicts the potential of adopting these γ-Fe2O3
nanorods as suitable material electrodes in electrochemical energy-storage devices.
Description
Keywords
Citation
DOI : 10.1007/s40097-020-00348-8