Recent Advances in Manganese Oxide Nanocrystals: Fabrication, Characterization, and Microstructure

This review introduces in detail the current state of the synthesis, characterization and microstructure of manganese oxide architectures including Mn2O3 and Mn3O4. Manganese oxide nanocrystals are promising strategic materials in the fabrication of novel nanostructures with controllable size, morphology, and properties. With recent advances in the field of transition metal oxide nanofabrication techniques, smart artificial manganese oxide nanocrystals would attract increasing attention and find many uses in a variety of applications including ion-exchange, molecular adsorption, catalysis, electrochemical reaction, batteries, optics, electronics, magnetism, mechanics, acoustics, and sensing. Some of these properties are tunable based on the adjustment of the related fabrication processes and the structural parameters of the nanostructures. Because of these interesting and tunable properties, some of the fabricated nanostructures are close to being incorporated into micro/nanodevices. Many research efforts have been devoted to developing new strategies for fabricating nanostructures owing to their widespread potential applications. Our focus in this review has been limited to those solution-liquid-solid chemical reaction strategies in which the solution-liquid-solid mechanism has been extensively and intensively studied and the nanocrystals formation processes are generally applicable to many materials. The literature discussed in this review represents part of the challenging ongoing work aimed at elucidating a detailed understanding of the interaction between artificial nanostructures and macroscopic systems. This area of research is still in its infancy, both with respect to the reproducible synthesis of nanostructures and understanding the detailed mechanisms that influence material characterization and advanced functions, so there is still much insight to be gained. It is also a young and quickly growing research field located at the crossroads of physics, chemistry, materials science, biology, and nanotechnology. The approaches described employ solution-liquid-solid chemical reaction with diverse morphologies at multiscales, and yield nanomaterials that inherit the natural morph structures. Therefore, unique and amazing properties can be expected from manganese oxide materials as a result of combining microstructures with synthetic techniques. © 2012 American Chemical Society.