Synthesis of Manganese Oxides Nanowires by a Facile Hydrothemal Method

Abstract

In this work, manganese oxides nanowires (α- and β-MnO2) were prepared starting from the corresponding commercial MnO2 powders under facile hydrothermal treatment in the presence of ammonia. High-quality α-MnO2 single-crystal nanowires were obtained using commercial α-MnO2 powders as precursor by hydrothermal treatment at 130°C for 24 h. Under hydrothermal treatment of commercial β-MnO2 powders at 180 oC for 24 h, high-quality β-MnO2 single-crystal nanowires were obtained. The obtained α- and β-MnO2 products consist almost entirely of nanowires with the diameters of 5–80 nm, and lengths ranging from several tens to several hundreds of micrometers. The growth of manganese oxides nanowires occurred via a dissolution-recrystallization process. Such high quality nanowires with high aspect ratio have a variety of promising applications. The simplicity of hydrothermal process, cheapness, and availability of raw materials, without the need of catalyst or template, are advantages favoring industrial manufacturing in scaled-up process by the novel method. X-ray, scanning electron microscopy, transmission electron microscopy, and electron diffraction have been employed to characterize these materials.