Facile Synthesis and Characterization of Pyrolusite, β-MnO2, Nano Crystal with Magnetic Studies

Abstract

MnO2 nanoparticles have been synthesized by a simple combustion method using MnSO4.4H2O. The crystalline phase, morphology, optical property and magnetic property of the as prepared nanoparticle were characterized using XRD, FT-IR, FTRaman, SEM, UV-Vis, PL and VSM respectively. Structural studies by XRD indicate that the synthesized material as tetragonal rutile crystal structure. FT-IR and FT-Raman analysis revealed the stretching vibrations of metal ions in tetrahedral co-ordination confirming the crystal structure. The PL and UV analysis having an emission band at 390 nm, showed a prominent blue peak at 453 nm as well as a green emission lines at 553 nm with band gap energy of 3.2eV. Magnetic measurements indicate that the Néel temperature of the β-MnO2 structures is 92.5K for Hc = 100 Oe which showed antiferromagnetic behaviour.

A Comparative Study of Optical and Magnetic Properties of Undoped and Cobalt Doped Manganese Oxide Nano Particles

“…A close interpretation of the FTIR spectra reveals metal oxides generally give absorption bands below 1000 cm - and a weak asymmetric band at 1566.20 cm -1 support the presence of hydroxyl (-OH) group due to the absorption of water by nanoparticle during the sample preparation [10]. The wavenumber 2299.15 cm -1 and 2376.30 cm -1 assigned to the CO 2 mode.The CO 2 modes are present in the FTIR spectra not owing to the serious contamination in Co doped MnO 2 but these modes due to atmospheric CO 2 in the samples.…”

Spectroscopic and Superparamagnetic Behaviour of Hausmannite Manganese Oxide Nanoparticles

“…4. In this spectrum, the absorption bands in the range of 400-700 cm -1 denotes the stretching and bending vibrations of [MnO]n [10]. FTIR absorption bands of Mn3O4 nanoparticles were exhibited in the spectrum with the bands 667, 615, 527 and 412 cm -1 .…”

“…The magnetic measurement represents the antiferromagnetic behaviour of manganese oxide nanowires [9]. Sherin and Thomas [10] reported the synthesis of MnO2, crystallite size 23 nm determined by using powder XRD and magnetic measurements. Shokoohi et al [11] investigated optical characteristics of manganese tetraoxide nanoparticles.…”

“…A large band at 3265 cm -1 due to stretching vibrations of the -OH bond and the other bands at 1641, 1416 and 1028 cm -1 attributed to -OH bending modes. The FTIR spectrum indicates that water molecule present in the sample, which is very essential for function of battery [10].…”

“…The particle sizes are not exactly same size, thus the average size of the particles are in the range 30 to 40 nm which is very agreed with the XRD results. The different sizes of nanoparticles are uniformly distributed and indicate the cluster of nanoparticles [10]. Optical studies by UV-visible spectrum: UV-visible spectrum illustrates that pure Mn 3 O 4 nanoparticles exhibits maximum absorption at 396 nm, which is the effect of quantum confinement [22].…”