Nanomaterials manganese oxides

N anomaterials have been around for hundreds of years and are typically defined as particles of size ranging from 1 to 100 nm in at least one dimension. The inorganic nanomaterial catalysts discussed here are manganese oxides and titanium dioxide. Outside the scope of this chapter are polymers, pillared clays, coordination compounds, and inorganic-organic hybrid materials such as metal-organic frameworks. 

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. 

Multigram quantities of manganese oxide (K-OMS-2) nanomaterials have been prepared using microwave heating and standard reflux glassware. The reactions were performed using aqueous/organic solvent mixtures. In the case of a water/DMSO mixture, the crystalline cryptomelane phase was formed within 10 min and the relative... 

The results from both syntheses have indicated that tailoring the polymer template for a specific metal precursor could yield functional nanomaterials with highly controlled properties. The nanoflakes of manganese oxide and cobalt hydroxide were synthesized with mosaic interiors that were ascribed to a stepwise crystal growth. Similar to the formation shown in Figure 1.11, this growth can be understood as a series of inhibitions and regrowths at the defect sites, as demonstrated previously for the echinoderms. 

Hydrothermal synthesis of structure- and shape-controlled manganese oxide octahedral molecular sieve nanomaterials. Advanced Functional Materials, 16,... 

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