Research On Bio-inspired Synthesis Of Two-dimensional Ultrathin Metal Oxide Nanomaterials And Its Electrochemical Properties

The highly ordered hierarchical structure leads to excellent properties of biominerals.Thus,recently the issue that synthesizing functional materials by using bio-inspired methods has become a hot research area.Researchers have found that bio-macromolecules or assembly aggregates can induce the nucleation and the oriented growth of biominerals due to a mass of ordered charges or functional groups existing on the surface of bio-macromolecules or assembly aggregates which play a significant role in determining the shape,structure and properties of the final biominerals.Charged two-dimensional ultrathin nanomaterials are analogous to bio-macromolecules or supramolecular polymer assemblies and can be used to induce the nucleation and the oriented growth of various functional materials due to the special surficial electronic properties.Based on the above illustration and the basic theory of biomineralization,we chose charged ultrathin CuO nanosheets as templates and inducers to control the growth process of tin-doped ultrathin hematite/copper oxide composite nanomaterials.The activities of electrocatalytic CO₂ reduction and lithium-ion battery for Sn-Fe₂O₃ UNSs have been explored.The main results of this dissertation can be summarized as follows:1.A synthesis system that using PVP-stabilized CuO nanoplatelets as templates and inducers to synthesize composite functional materials has been successfully established,and tin-doped ultrathin hematite nanosheets?Sn-Fe₂O₃ UNSs?have been synthesized successfully.In this process,PVP has an important influence on the morphology of the final product.In addition,the formation mechanism of Sn-Fe₂O₃ UNSs has been illustrated in detail through a series of time experiments.This method can be extended to the controllable synthesis of other inorganic composite functional nanomaterials,and also provides valuable clues for a deeper understanding of the biomineralization process.2.The application of Sn-Fe₂O₃ UNSs in the electrocatalytic CO₂ reduction and lithium-ion battery has been investigated systematically.When sodium bicarbonate solution was used as the electrolyte,Sn-Fe₂O₃ UNSs exhibited an approximately 92%faradaic efficiency of methanol at-1.3 V vs.SCE with a current density of 25 mA/cm2.At the same time,in the lithium-ion battery test,the specific capacitance of Sn-Fe₂O₃ UNSs reached 1089.7 mAh/g after 100 cycles of charge/discharge at a current density of 100 mA/g.In addition,it maintained a high specific capacitance of 540.6 mAh/g at a high current density of 2000 mA/g.This work illustrates the effects of doped Sn atoms on the activities of electrocatalytic CO₂ reduction and lithium-ion battery by using Sn-Fe₂O₃ UNSs as a model.