Hydrothermal Synthesis of Structure‐ and Shape‐Controlled Manganese Oxide Octahedral Molecular Sieve Nanomaterials

Li, W.-N.; Yuan, Jinjiang; Shen, Xiongfei; Gomez-Mower, Sinue; Xu, Linping; Sithambaram, Shanthakumar; Aindow, Mark; Suib, Steven L.

doi:10.1002/adfm.200500504

Cited by 219 publications

(134 citation statements)

References 35 publications

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“…The Raman spectrum of β-MnO2 nanopowder in figure 1c has three bands at 629, 538 and 498 cm −1 which agrees well with the previous reports on the β-MnO2 phase [15]. The Raman band at 629 cm −1 is attributed to the B2g mode and involves antisymmetric Mn-O vibrations.…”

Section: Resultssupporting

confidence: 80%

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

Sherin¹,

Thomas²,

Manoj³

2015

IJSEA

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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.

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Section: Resultssupporting

confidence: 80%

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

Sherin¹,

Thomas²,

Manoj³

2015

IJSEA

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“…For example, partial exchange of K + ions in the K-OMS-2 tunnels with H + ions (protons) has yielded excellent acid catalysts for selective oxidation reactions, [ 18 ] whereas doping of single-type, low-, or high-valent metal cations, such as Co 2 + , Zr 2 + , Cu 2 + , Cr 3 + , Fe 3 + , In + 3 , V 5 + , W 6 + , and Mo 6 + into the framework, [19][20][21][22][23][24][25] via a subtle balance of the redox properties and depending on the extent of substitution, has produced cryptomelane with novel morphologies [ 26 ] and catalytic properties. [ 27 ] In terms of morphology, doping Cr 3 + into the K-OMS-2 structure produced well-ordered dendritic structures, which are unusual compared to the regular K-OMS-2 morphology.…”

Section: Introductionmentioning

confidence: 99%

Manganese Oxide Octahedral Molecular Sieves (OMS-2) Multiple Framework Substitutions: A New Route to OMS-2 Particle Size and Morphology Control

et al. 2010

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Self-assembled multidoped cryptomelane hollow microspheres with ultrafi ne particles in the size range of 4-6 nm, and with a very high surface area of 380 m 2 g − 1 have been synthesized. The particle size, morphology, and the surface area of these materials are readily controlled via multiple framework substitutions. The X-ray diffraction and transmission electron microscopy (TEM) results indicate that the as-synthesized multidoped OMS-2 materials are pristine and crystalline, with no segregated metal oxide impurities. These results are corroborated by infrared (IR) and Raman spectroscopy data, which show no segregated amorphous and/or crystalline metal impurities. The fi eld-emission scanning electron microscopy (FESEM) studies confi rm the homogeneous morphology consisting of microspheres that are hollow and constructed by the self-assembly of pseudo-fl akes, whereas energy-dispersive X-ray (EDX) analyses imply that all four metal cations are incorporated into the OMS-2 structure. On the other hand, thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC) demonstrate that the as-synthesized multidoped OMS-2 hollow microspheres are more thermally unstable than their single-doped and undoped counterparts. However, the in-situ XRD studies show that the cryptomelane phase of the multidoped OMS-2 hollow microspheres is stable up to about 450 ° C in air. The catalytic activity of these microspheres towards the oxidation of diphenylmethanol is excellent compared to that of undoped OMS-2 materials.

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“…Detailed experimental parameters are summarized in [11]. The black wool-like products were collected by centrifugation, washed several times with deionized water and ethanol, and vacuum dried at 80 o C for 8 h. The treatment of the MnO 2 was similar to the method reported previously [14].…”

Section: Sample Preparationmentioning

confidence: 99%

Magnesium microspheres and nanospheres: Morphology-controlled synthesis and application in Mg/MnO2 batteries

Cheng

et al. 2009

Nano Res.

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In this paper, we report on the morphology-controlled synthesis of magnesium micro/nanospheres and their electrochemical performance as the anode of primary Mg/MnO 2 batteries. Mg micro/nanoscale materials with controllable shapes have been prepared via a conventional vapor-transport method under an inert atmosphere by adjusting the deposition temperatures. Extensive analysis techniques including SEM, XRD, TEM/HRTEM, and Brunauer Emmett Teller (BET) were carried out to characterize the as-obtained samples. The results show that the Mg samples are microspheres or micro/nanospheres with specific surface areas of 0.61 1.92 m 2 /g. The electrochemical properties of the as-prepared Mg and commercial Mg powders were further studied in terms of their linear sweep voltammograms, impedance spectra, and discharge capability. By comparing the performance of different inhibitors in electrolytes, it was found that NaNO 2 (2.6 mol/L) as an inhibitor in the Mg(NO 3 ) 2 (2.6 mol/L) electrolyte affords a Mg electrode with high current density and low corrosion rate. In particular, the Mg sample consisting of microspheres with a diameter of 1.5 3.0 μm and nanospheres with a diameter of 50 150 nm exhibited superior electrode properties including negative initial potential ( 1.08 V), high current density (163 mA/cm 2 ), low apparent activation energy (5.1 kJ/mol), and high discharge specifi c capacity (784 mAh/g). The mixture of Mg nanospheres and microspheres is promising for application in primary Mg/MnO 2 batteries because of the suffi cient contact with the electrolyte and greatly reduced charge transfer impedance and polarization.

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Hydrothermal Synthesis of Structure‐ and Shape‐Controlled Manganese Oxide Octahedral Molecular Sieve Nanomaterials

Cited by 219 publications

References 35 publications

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

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

Manganese Oxide Octahedral Molecular Sieves (OMS-2) Multiple Framework Substitutions: A New Route to OMS-2 Particle Size and Morphology Control

Magnesium microspheres and nanospheres: Morphology-controlled synthesis and application in Mg/MnO2 batteries

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