Manganites

Manganaies IV), manganites. Mixed-metal oxides containing Mn(IV). Prepared by solid state reactions. 

Manganerz, n. manganese ore. — graues manganite pyrolusite. — schwarzes —, hausrnannite. 

The relatively high cost and lack of domestic supply of noble metals has spurred considerable efforts toward the development of nonnoble metal catalysts for automobile exhaust control. A very large number of base metal oxides and mixtures of oxides have been considered, especially the transition metals, such as copper, chromium, nickel, manganese, cobalt vanadium, and iron. Particularly prominent are the copper chromites, which are mixtures of the oxides of copper and chromium, with various promoters added. These materials are active in the oxidation of CO and hydrocarbons, as well as in the reduction of NO in the presence of CO (55-59). Rare earth oxides, such as lanthanum cobaltate and lanthanum lead manganite with Perovskite structure, have been investigated for CO oxidation, but have not been tested and shown to be sufficiently active under realistic and demanding conditions (60-63). Hopcalities are out-... 

Manganese Mn, at wt 54.94, brittle, silvery metal, mp 1245°, bp 2097°, d 7,44g/cc, Mohs hardness 5 decomps in w, readily dissolved in dil mineral acids. Usually associated with Fe ores in sub-marginal concns. Important ores of Mn are pyrolusite, manganite, psilomelane rhodochrosite. Prepd by reduction of the oxide with Al or C. Pure Mn is obtained electrolyti-cally from sulfate or chloride sain. It is used, in powd form, in the manuf of delay powds and in some pyrotechnic mixts. The requirements of the USA Armed Forces are covered by... 

Bianconi A, Saini NL (2005) Nanoscale Lattice Fluctuations in Cuprates and Manganites 114 287-330... 

Nanomaterials can also be tuned for specific purposes through doping. Specifically, the effect of the presence of manganese oxides on photocatalysis involving primarily titanium dioxide will be considered in this section. Titanium dioxide is a well-known photocatalyst and will be considered separately. K-OMS-2, which has a cryptomelane structure, is illustrated in Figure 8.4. Not all the literature discussed in this section, however, involves OMS tunnel structure materials. For example, amorphous manganese oxide (AMO) is also discussed as a photocatalyst. Manganite (MnOOH) is also included in battery applications. 

Battery applications Titanium containing y-Mn02 (TM) hollow spheres synthesis and catalytic activities in Li-air batteries [123] Orthorhombic LiMn02 nanorods for lithium ion battery application [124] Electrochemical characterization of MnOOH-carbon nanocomposite cathodes for metal—air batteries [125] Electrocatalytic activity of nanosized manganite [126]... 

Bastardis, R., Guihery, N., and Suaud, N. 2007. Relation between double exchange and Heisenberg model spectra application to the half-doped manganites. Physical Review B 75 132403 (1 1). 

Baythoun, M. S. G Sale, F. R. 1982. Production of strontium-substituted lanthanum manganite perovskite powder by the amorphous citrate process. /. Mat. Sci. 17 2757-2769. 

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