Formation of Na 0.44 MnO 2 nanowires via stress-induced splitting of birnessite nanosheets

Nano Research (Impact Factor: 6.96). 01/2009; 2(1). DOI: 10.1007/s12274-009-9003-1

ABSTRACT High aspect ratio Na 0.44 MnO 2 nanowires with a complex one-dimensional (1 D) tunnel structure have been synthesized. We found that the reaction went through layered birnessite nanosheet intermediates, and that their conversion to the fi nal product involved splitting of the nanosheets into nanowires. Based on our observations, a stress-induced splitting mechanism for conversion of birnessite nanosheets to Na 0.44 MnO 2 nanowires is proposed. The fi nal and intermediate phases show topotaxy with001 f // 020 b or110 b where f represents the fi nal Na 0.44 MnO 2 phase and b the intermediate birnessite phase. As a result of their high surface areas, the nanowires are effi cient catalysts for the oxidation of pinacyanol chloride dye.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Graphene oxide/manganese oxide/polyaniline composite (GOM) was synthesized via one-step method at room temperature, and its reduced graphene oxide/manganese oxide / polyaniline (RGOM) composites were prepared under different reaction conditions. The relationships of synthesis approach, structure and electrochemical properties of the manganese oxide ternary composites were systematically investigated. The reaction temperature and the basic concentration played important roles in the reduction process. The possible reaction mechanisms of the ternary composites were proposed. The results show that high temperature under hydrothermal condition can lead to the higher crystalline degree, and promote the formation of its fiber-like nanostructure of the composites. Meanwhile, the higher concentration of NaOH promotes the reduction of MnO2 to other manganese oxides with a lower valence. The electrochemical characterization shows that, among those composites, the specific capacity of RGOM5 with a rough and sheathed nanostructure, obtained using 8 M NaOH at 120 ℃ via a hydrothermal method, can reach 344 F•g-1 at a scan rate of 1 mV•s-1, and the capacitive retention proportion remains nearly 100% after 6000 cycles, which presents a promising future for RGOM composites acting as low cost energy storage materials.
    RSC Advances 10/2014; 4(100). DOI:10.1039/C4RA06360K · 3.71 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Novel ultra-long Na0.44MnO2 submicron slabs were fabricated through the sol–gel method, followed by high-temperature calcination. The material has a thickness ranging from 100 to 250 nm and a length varying from 10 μm to 40 μm. Electrochemical characterization indicates that the material can deliver a high capacity, larger than 120 mA h g−1 with stable cycling over 100 cycles in assembled non-aqueous Na-ion cells, the good performance of which is mainly attributed to the reduced sodium ion diffusion distance.
    RSC Advances 08/2014; 4(72). DOI:10.1039/C4RA07355J · 3.71 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Sodium manganese oxides (SMO) with different crystal structures have been synthesized by high-temperature solid-state reaction (HTSSR), in which both morphology and crystal structure of SMO can be well-controlled by synergistic effects of both the ratio of sodium-to-manganese and the heat-treatment temperature. The material is further used as the cathode in Li/Na-ion batteries, and the experimental results indicated that the performance of SMO as the electrode material mainly depends on its crystal structure, while its morphology only plays an important role in the initial stage. SMO with a 3-D tunnel structure (Na0.44MnO2) and a layer structure (Na0.67MnO2 and Na0.91MnO2) delivers better battery performance.
    RSC Advances 01/2014; 4(57):30340. DOI:10.1039/C4RA03735A · 3.71 Impact Factor

Full-text (4 Sources)

Available from
Jun 5, 2014