Controlled synthesis of Mn3O4 nanoparticles in ionic liquids

Abstract

This work describes a simple one-step synthesis of Mn3O4 nanoparticles by thermal decomposition of [Mn(acac)2] (acac = acetylacetonate) using imidazolium ionic liquids (ILs) and a conventional solvent, oleylamine, for comparison. The Mn3O4 nanoparticles were characterized by XRD, ATR-FTIR, TEM, Raman, UV/VIS and magnetometry techniques. The addition of 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide IL (BMI·NTf2) yielded a smaller particle size (9.9 ± 1.8 nm) with better dispersion and more regular sizes than synthesis using oleylamine as the solvent (12.1 ± 3.0 nm). The complete conversion of the precursor to Mn3O4 nanoparticles occurred after 96 h at 180 °C for the reaction performed in BMI·NTf2. However, under these reaction conditions in oleylamine, no precursor was detected, but two different phases were observed: a major phase corresponding to Mn3O4 and a minor phase corresponding to MnO2. Magnetometry revealed that Mn3O4 nanoparticles synthesized in either oleylamine or BMI·NTf2 exhibited ferrimagnetic behavior at low temperatures, whereas they were paramagnetic at room temperature. As expected, the blocking temperature and the coercivity decreased with the size of nanoparticles. Our results demonstrate that reaction conditions such as time, and the nature of the ionic liquid play important roles in determining the size of Mn3O4 nanoparticles.

In Situ Synthesis of Mn3O4 Nanoparticles on Hollow Carbon Nanofiber as High‐Performance Lithium‐Ion Battery Anode

“…To further determine structural information, Raman spectroscopy was performed (Figure b). A very strong band at 644 cm −1 , along with a weak band at 348 cm −1 , are consistent with those reported in the literature for Mn 3 O 4 . The strong band at 640 cm −1 is assigned to the Mn−O breathing vibration of divalent manganese ions in tetrahedral coordination, which is found in the mineral hausmannite.…”

“…Av ery strong band at 644 cm À1 ,a long with aw eak band at 348 cm À1 ,a re consistentw ith those reported in the literature for Mn 3 O 4 . [29,30] The strong band at 640 cm À1 is assigned to the MnÀOb reathing vibration of divalent manganese ions in tetrahedral coordination,w hichi sf ound in the mineral hausmannite. In addition, aDband at 1348 cm À1 and aGband at 1598cm À1 is typical for carbon.…”

‘Green’ synthesis of metals and their oxide nanoparticles: applications for environmental remediation

“…Bussamara et al have performed a comparative study by controlling the synthesis of manganese oxide (Mn 3 O 4 ) nanoparticles using imidazolium ionic liquids and oleylamine (a conventional solvent). They found that smaller sized nanoparticles (9.9 ± 1.8 nm) were formed with better dispersity in ionic liquids than in the oleylamine solvent (12.1 ± 3.0 nm) [ 46 ]. Lazarus et al synthesized silver nanoparticles in an ionic liquid (BmimBF4).…”

Synthesis, phase transformation, and morphology of hausmannite Mn3O4 nanoparticles: photocatalytic and antibacterial investigations

“…In thermal decomposition method, Ahmad Morsali and co-workers [66] used a coordination compound, Mn (pyterpy) (H 2 O) (N 3 ) (NO 3 )) as a precursor dissolved in oleic acid, subjected to thermal decomposition at 320 C for 2h under nitrogen atmosphere to fabricate Mn 3 O 4 nano particles. Additionally, Robert Bussamara and his group [67] have prepared similar tetragonal Mn 3 O 4 in controlled manner using manganese precursor and one of the ionic liquids such as 1-n-butyl-3-methylimidazoliumhexa fluoro phosphate (BMI PF6), 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMI⋅BF4), and 1-n-butyl-3-methylimidazoliumbis(trifluoromethanesulfonyl)imide (BMI⋅NTF2) dissolved in oleylamine solvent. It was noticed that Mn 3 O 4 was formed only in the combination of oleylamine and BMI NTF2 solution but failed to get Mn 3 O 4 nano in other two ionic solutions due to the decomposition of ionic liquid (IL).…”