One-Dimensional Nanostructures from Layered Manganese Oxide

Abstract

In this paper, we report the preparation of one-dimensional (1D) nanostructures from layered compounds (2D). γ-MnOOH nanorods were successfully prepared from platelike layered Na-birnessite by simple hydro(solvo)thermal treatment at low temperature. It was observed that the reaction medium plays an important role in the phase and morphology modifications. The γ-MnOOH was thermally treated under different conditions of atmosphere (inert or oxidizing) and temperature, which led to several phases of manganese oxide nanorods, such as MnO2 (pyrollusite), Mn2O3 (bixbyite), and Mn3O4 (hausmannite). Indeed, the achievement of such phase tuning was possible because of the outstanding structural flexibility of manganese oxides. Considering the simplicity, reproducibility, and high yield of these methods, they may be employed for low-cost large-scale production of one-dimensional manganese oxide nanostructures.

Nanosized Carbon‐Supported Manganese Oxide Phases as Lithium–Oxygen Battery Cathode Catalysts

“…Once a pristine MnO x phase is obtained, it is possible to synthesize a different polymorph from it by using different treatments. By using this approach and inspired by the work of Ferreira et al.,50 we prepared β‐MnO 2 on carbon starting from the orthorhombic δ‐MnO 2 /C synthesized according to Equation (2). [Notably, hexagonal δ‐MnO 2 /C prepared according to Eq.…”

Porous magnetic manganese oxide nanostructures: Synthesis and their application in water treatment

“…According to line S2 in Fig. 1, all the diffraction peaks can be indexed to the mixtures form of birnessite (JCPDS 23-1046) [22], tetragonal hausmannite structure (space group I41/amd) of Mn 3 O 4 with lattice constants of a = b = 5.762 Å, and c = 9.470 Å (JCPDS 24-0734) [9,37], and bixbyite (space group pcbb/61) of Mn 2 O 3 with lattice constants of a = 9.416 Å, b = 9.424 Å, and c = 9.405 Å (JCPDS 24-0508) [38][39][40]. All the XRD results show the components of the structures and potential chemical changes take place in both the Baeyer reaction and thermal treatment.…”

Controllable synthesis of α- and β-MnO2: cationic effect on hydrothermal crystallization

“…Via the same reaction as Wang et al and with the assistance of silver foil or silver cation catalyst, Li et al [31] prepared α-MnO 2 at room temperature, obtaining β-MnO 2 hydrothermally at 80 • C. In addition, Subramanian et al [32] In addition, obtaining one polymorph from another was another strategy; for example, Wei et al [33] successfully transformed γ -MnO 2 into αand β-MnO 2 at 140 and 170 • C, respectively. Ferreira et al [34] employed hydrothermal transformation in a dodecylamine aqueous solution, from δ-MnO 2 into MnOOH, which can be subsequently annealed at 300-500 • C to form β-MnO 2 . In addition, Shen et al [26] reported a transformation from δ-MnO 2 into other polymorphs of MnO 2 with (2 × 4), (2 × 3) and (1 × 1) tunnel structure at pH = 13, 7 and 1, respectively; the pH value is believed to affect the formation of polymorphs significantly.…”