One-pot and green synthesis of Mn3O4 nanoparticles using an all-in-one system (solvent, reactant and template) based on ethaline deep eutectic solvent

Abstract

Mn3O4 nanoparticles have been synthesized using a facile and sustainable method using ethaline (ethylene glycol–choline chloride) deep eutectic solvent (DES). The as-synthesized nanoparticles have been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, UV/vis absorption spectroscopy, and vibrating sample magnetometry (VSM). The XRD results point to crystallization of hausmannite Mn3O4 in tetragonal crystal structure with average crystallite size of 18 nm. The microscopy-elemental investigations suggest the synthesis of spherical nanoparticles with average particle size of 25 nm and high elemental purity. The obtained band gap of 3.4 eV for the as–synthesized Mn3O4 nanoparticles indicates the semiconductor nature of nanoparticles. FTIR absorption bands further confirm the formation of pure Mn3O4 nanoparticles. The magnetic characterization of as-synthesized Mn3O4 nanoparticles clearly reveals their paramagnetic behavior at room temperature. Based on our proposed mechanism the ethaline plays a triple role (solvent, reactant, and template) during the synthesis thereby it provides a green all-in-one system for synthesis, stabilization and better control over growth of Mn3O4 nanoparticles.