A Friendly Environmental Route for the Fabrication of Spinel Co3O4 Nanorods, Using Inorganic Precursor Salt and Aqueous Extracts of Moringa oleifera Leaves

Abstract

Nowadays many researchers are focused on the sytnhesis of nanoscale tricobalt tetraoxide (Co3O4) particles, owing to their unique properties. These particles have indeed many potential technological applications. The present investigation deals with the fabrication of this spinel oxide: it was successfully synthesized through a friendly environmental method, using cobalt (II) chloride as cobalt precursor and aqueous extract of Moringa oleifera leaves. The latter contains alkaloids as a base source while flavonoids present in the leaves acted as capping agent to prevent the particles agglomeration. Alkaloids present in the leaves were hydrolyzed in water and consequently, hydroxilated Co2+ leads to the formation of Co3O4 powder via calcination. The electronic transmission microscopy has revealed the single crystalline nanorods morphology of the synthetised materials. These nanorods are about several hundred nanometers long and several tens of nanometers in diameter. The bulk Co3O4 is known to be antiferromagnetic, the vibrating sample magnetometer data (at room temperature) of the prepared powder exhibited the lower coercivity and remanence, signaling that the produced spinel was pure and was constituted of superparamagnetic particles made of Co3O4. The UV–visible spectrum exhibited a photoluminescence peak in the visible light range positioned at about 538nm, suggesting this spinel as a visible light emitting material and as photocatalyst under visible light.