Manganese Oxide Micro-Nano Materials Based On Mn(?) Complex Precursors

Manganese is a kind of transition metal element which is abundant and environmentally friendly.It exist a variety of stable valence states and usually exist as variety of manganese oxides in nature.Manganese oxide system is complex since it has a lot of special structures.A variety of manganese oxides with special structures have potential applications in the catalyst,sensors,secondary batteries,supercapacitors and other fields.The manganese oxides prepared by different methods usually have unique physical and chemical properties.This phenomenon provides the basis for the design of new methods to prepara manganese oxide materials.Therefore,the research on manganese material is mainly concerned with manufacturing oxide micro-nano materials with special shape and excellent physical and chemical properties through various means to further expand their application in various fields.Based on this situation,the research work of this paper can be divided into the following two parts.The first part is the preparation and research of novel Mn???complex precursor.With organic ligands and+2-valent manganese ions as raw materials,9 kind new complexes with different dimensions were synthesized by using solvent and hydrothermal methods which were commonly used in the synthesis of complexes.Complexes 1,2 and 3 are three-dimensional frameworks,complex 4 is two-dimensional network structure,complex 8 is one-dimensional chain structure,and the others are zero-dimensional structures.The complexes were characterized by infrared spectroscopy,thermogravimetric analysis and so on.The exact structures of complexes were determined by X-ray single crystal diffraction.The morphological characteristics of the complexes were studied by scanning electron microscopy.In the second part,complexes were used as the precursor and calcined in the muffle furnace at different temperatures,respectively,to obtain a series of manganese oxide micro-nano materials.The material phases of these materials were confirmed,while their micro-shape appearance was analyzed.The results show that the materials are composed of Mn₂O₃ or Mn₂O₃ and Mn₃O₄,and their microstructure pictures show that they are composed of nanometer or micrometer basic structures such as spherical,elongated and irregular polyhedron.The manganese oxide materials are similar to the precursors.The electrochemical properties of manganese oxide material electrode were investigated in 1.0 mol·L^-1 Na₂SO₄electrolyte by cyclic voltammetry and constant current charge/discharge test.The results show that the manganese oxide prepared above has good cycle stability as the supercapacitor electrode material,and it is also found that the material with the composition of Mn₃O₄ and Mn₂O₃ has higher specific capacitance.