A study on the development of high-power supercapacitor materials based on formation of thick mesoporous MnO2 shells on a highly conductive 3D template using vertically aligned carbon nanofibers (VACNFs). Coaxial manganese shells of 100 to 600 nm nominal thicknesses are sputter-coated on VACNFs and then electrochemically oxidized into rose-petal-like mesoporous MnO2 structure. Such a 3D MnO2/VA...

MnO2 supported on graphene oxide (GO) made from different graphite materials has been synthesized and further investigated as electrode materials for supercapacitors. The structure and morphology of MnO2-GO nanocomposites are characterized by X-ray diffraction, X-ray photoemission spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and Nitrogen adso...

Hybrid nanomaterials based on manganese, cobalt, and lanthanum oxides of different morphology phase compositions were prepared using a facile single-step ultrasonic spray pyrolysis (USP) process tested as electrocatalysts for oxygen reduction reaction (ORR). The structural morphological characterizations completed by XRD SEM-EDS. Electrochemical performance was characterized cyclic voltammetry ...

In the current work, Punica granatum L. peel, Artemisia herba-alba Asso., Matricaria chamomilla L., and Camellia sinensis extracts were used to prepare manganese dioxide (MnO2) nanoparticles utilizing a green method. Energy-dispersive X-ray (EDX) analysis, Fourier Transform Infrared Spectroscopy (FTIR) Filed emission-scanning electron microscopy (FE-SEM) analysis evaluate produced MnO2 NPs. FE-...

δ-MnO2/o-MWCNTs were synthesized by coating MnO2 spontaneously on oxidized multi-walled carbon nanotubes via simple immersion of the o-MWCNTs into KMnO4 solution. This catalyst comprising the outer region of catalytic MnO2 and the inner region of highly conductive o-MWCNTs enhanced photocatalytic water oxidation activity.

Polyaniline (PANI) and MnO2/PANI composites are simply fabricated by one-step interfacial polymerization. The morphologies and components of MnO2/PANI composites are modulated by changing the pH of the solution. Formation procedure and capacitive property of the products are investigated by XRD, FTIR, TEM, and electrochemical techniques. We demonstrate that MnO2 as an intermedia material plays ...

The electrocatalytic activities of the MnO2/C composites are examined in Li-O2 cells as the cathode catalysts. Hierarchically mesoporous carbon-supported manganese oxide (MnO2/C) composites are prepared using a combination of soft template and hydrothermal methods. The composites are characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, small...

Electrolytic Manganese Dioxide (EMD) material was analyzed by Rietveld refinement of x-ray diffraction patterns to answer the question, “Is EMD composed of gammaor epsilon-MnO2?” An electron diffraction study of EMD using a 20 nanometer spot size electron beam reported observing only the ε-MnO2 structure and no γ-MnO2 structure. However, a Transmission Electron Microscopy (TEM) study of EMD obs...

Recently, manganese-oxide compounds have attracted considerable attention, in particular, as candidate materials for photochemical water-splitting reactions. Here, we investigate electronic states of pristine manganese dioxides (MnO2) in different crystal phases using spin-polarized density functional theory (DFT) with Hubbard U correction. Geometrical structures and band dispersions of α-, β-,...