Synthesis And Characterization Of Novel Misfit-layered Transition Metal-Manganese Oxide Compounds

There are two subsystems with different unit cell dimensions in the misfit-layered compounds. The misfit-layered compounds are very interesting because of their unusual structures as well as their properties, and have great potential applications in the fields of the electronic materials, the optic materials, the electrical materials, the magnetic materials, the catalytic materials and so on.Birnessite is a layered manganese oxide. It has attracted considerable interest due to its potential applications in the heterogeneous catalysis, the chemical sensors, the treatment of the toxic waste water, the rechargeable battery and so on. In this thesis, we mentioned the synthesis of a series of misfit-layered transition metal manganese oxide compounds by using birnessite as the precursor, and the investigation on the conditions of the synthesis reactions. The structures, compositions, and physical and chemical properties of these compounds have been studied by XRD, IR, TG-DTA, SEM, TEM, ICP.I have synthesized the misfit-layered copper manganese oxide compounds (CMO), CuMn_2.22O_5.25·2.04H)2O, by using hydrothermal synthesis. There are two sublattices in CMO, i.e. the pseudo-hexagonal sublattice for MnO₂ and the orthorhombic sublattice for CuO, and the two sublattices are incommensurate along the a direction. The lattice parameters are as follows: for MnO₂ pseudo-hexagonal sublattice:a₁=0.282nm, c₁ =0.942nm; for CuO orthorhombic sublattice:a₂=0.578nm, b₂=0.276nm, c₂=0.942nm。Copper manganese oxide compounds (CMO) loses all of water during 200-450℃, and when the temperature is over 450℃, it loses oxygen and is transformed into a mixture of CuMn₂O₄ and Mn₃O₄. Both misfit layered copper manganese oxide (CMO) and birnessite show catalytic activity in the epoxidation of styrene, and CMO is better than birnessite.The misfit-layered zinc manganese oxide (ZMO), ZnMn2.15O5.16·3.39 H2O, has been hydrothermally synthesized.Zinc manganese oxide compound (ZMO) can also show catalytic activity in the epoxidation of styrene, and the catalytic effect of ZMO is better than that of birnessite, but is not better than that of CMO. Zinc manganese oxide compound (ZMO) loses all of water during 200-400℃, and when the temperature is over 400℃, it loses oxygen and is transformed into a mixture of ZnMn₂O₄ and Mn₃O₄. The misfit-layered cobalt manganese oxide (COMO), CoMn_2.18O_5.23·1.42 H₂O, has been hydrothermally synthesized. There are two sublattices in COMO, i.e. the pseudo-hexagonal sublattice for MnO₂ and the orthorhombic sublattice for CoO, and the two sublattices are incommensurate along the a direction. The lattice parameters are as follows: for MnO₂ pseudo-hexagonal sublattice:a1=0.267nm, c1 =0.936nm; for CoO orthorhombic sublattice:a2=0.494nm, b2=0.289nm, c2=0.936nm。The cobalt manganese oxide (COMO) loses all of water during 200-400℃, and when the temperature is over 400℃, it loses oxygen and is transformed into a mixture of CoMn2O4 and Mn3O4.