Synthesis of MnOOH nanorods by cluster growth route from [Mn 12O 12( RCOO) 16(H 2O) n] ( R=CH 3, C 2H 5). Rational conversion of MnOOH into Mn 3O 4 or MnO 2 Nanorods

Abstract

Single-crystalline nanorods of γ-MnOOH (manganite) phase with diameters of 120 nm and lengths of 1100 nm have been prepared using a new cluster growth route under low-temperature hydrothermal conditions starting from [Mn 12O 12(CH 3COO) 16(H 2O) 4]·2CH 3COOH·4H 2O or [Mn 12O 12(C 2H 5COO) 16(H 2O) 3]·4H 2O without any catalyst or template agents. The so-obtained nanorods were studied by X-ray diffraction (XRD), infrared (IR) spectroscopy, Raman spectroscopy and high resolution transmission electron microscopy (HRTEM). Their thermal conversion opens an access to Mn 3O 4 (hausmannite) and β-MnO 2 (pyrolusite) nanorods, respectively, under argon or air atmosphere. A coercive field of 12.4 kOe was obtained for the Mn 3O 4 nanorods.