Abstract
Herein, we report the synthesis of spinel cobalt oxide nanorods (Co
3
O
4
NRs) by a modified co-precipitation approach and examine their larvicidal activity against
Culex pipiens.
The structure and morphology of the as-prepared Co
3
O
4
NRs were emphasized using X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDAX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It was found that Co
3
O
4
nanostructures have a face-centered spinel cubic crystal structure with a mean crystallite size of 38 nm. These nanostructures have a rod like shape with a mean diameter of 30 nm and an average length of 60 nm. The TGA measurements revealed the high stability of the formed spinel cubic structure at 400 °C. The optical behavior indicates the direct transition of electrons through an optical band gap in the range of 2.92–3.08 eV. These unique chemical and physical properties of Co
3
O
4
NRs enabled them to be employed as a strong agent for killing the
C. pipiens
. A comparison study was employed between the as-prepared Co
3
O
4
and the entomopathogenic fungus
Metarhizium brunneum
as a control agent of
C. pipiens
larvae. The results revealed that the as-prepared nanorods have higher mortality against
C. pipiens
larvae compared with the well-known
M. brunneum
.