| In recent years,metal oxide micro/nano structures have stimulated much scientific and technological interest because of their promising applications in electronics,catalyst,optics, gas sensors,etc.Chemical preparation of novel micro/nanostructures and the investigation of their general formation processes may be a solution to the precise control of their sizes, structures and properties.It is of great significance to tailor the property of materials in a controllable way by altering their structure,morphology,or composition.In this dissertation, systematic explorations have been carried out on new synthetic strategies of metal oxides based on the chemical solution method.We have realized the control of micro/nano structures of materials during the synthesis process,and established some new routes to fabricate metal oxide materials.The main points can be summarized as follows:1.Nanoarrays based on nanodevice and quantum device have been a hot research topic, solution-based routes were developed to the chemical synthesis and simultaneous assembly of nanostructures into metal oxide nanoarrays.Specifically,a corrosion-based strategy has been successfully designed to synthesize ZnO nanorod arrays in the Cl- anion solution by employing cell reaction.The gerenal principle for the synthesis of nanorod arrays materials has been discovered by exploring their formation processes.In particular,a phase transformation has been discovered for the preparation of monoclinic Nb2O5 nanotube arrays through using pseudo-hexagonal Nb2O5 nanorod arrays as the precursor.2.Hollow structured materials have attracted much attention because of their great potential applicatios in many fields,hollow metal oxide microspheres and tubes were prepared through the sacrificial template and in situ template method,respectively. Specifically,based on the solubility difference between reactant and production,hollow ZnO microspheres were fabricatred by the sacrificial template route.ZnO hollow microspheres were prepared by employing Zn5(CO3)2(OH)6 as the in situ sacrificial template at room temperature.The Kirkendall vacancy effect was used to interpret the formation process of hollow ZnO microspheres.According to ZnO characteristics of surface polarity and chemical activities,the hollow ZnO tubes were prepared through in situ template method based on acetic acid etching strategy.The etching of ZnO template with acetic acid results in the formation of tubular structures. 3.Meal oxide micro/nano structured materials have a variety of special properties,hence it is very important in both fundamental research and commercial applications,several metal oxide materials were fabricated by employintg Mg5(CO3)4(OH)2·4H2O as the reaction precursors through chemical solution method.Specifically,according to the growth habit of Mg5(CO3)4(OH)2·4H2O sheet-like structures,MgO hierachical structures consisted of nanosheets were fabricated by using Mg5(CO3)4(OH)2·4H2O as the precursors,which were prepared by a homogeneous reaction.Based on the fact that Mg5(CO3)4(OH)2·4H2O is a slightly soluble salt,a spontaneous ion replacement route by employing Mg5(CO3)4(OH)2·4H2O as the reagent to synthesize a number of metal oxides has been established.We present a comprehensive study on the ion replacement reaction for the chemical control synthesis of micro/nano structured Mn2O3,ZnO,CuO,CdO,Al2O3,and CaO samples.
|
PDF Full Text Request