Preparation And Application Of Transition Metal Oxide Nanomaterials

An innovative approach has been proposed to prepare transition metal oxide nanomaterials in this thesis.This method was based on plasma-enhanced thermal oxidation through the scale up of convention tubular furnace.X ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),transmission electron microscopy(TEM),Raman,photoluminescence(PL)and other tools testing were used to characterize nanomaterial crystal structure and morphology,and determine the quality and performance of the transition metal oxide nanomaterials.In the plasma-enhanced thermal oxidation,the morphology and microstructure of the synthesized single-crystal transition metal oxide nanomaterials could be controlled by changing the reaction temperature,the flow rate ratio of argon and oxygen gases,as well as the discharge power,etc.It was found that,when the reaction temperature was 300,350,400,450 and 500 ?,the synthesized zinc oxide nanorods were longer and more uniform with the increase of the reaction temperature.In the case of different flow rate ratios of argon and oxygen gases,no zinc oxide nanorods were synthesized at the flow rate ratios of argon and oxygen gases of 15:45 and 45:45,while zinc oxide nanorods could be grown on the zinc foil at the flow rate ratios of 45:15 and 45:5.In the case of different discharge currents of 0.3 A,1.3 A,and 2.3 A,the synthesized zinc oxide nanorods grew longer with the increase of the discharge current.The quality of copper oxide nanowires and iron oxide nanobelts at the reaction temperature of 400 and 600 ?,respectively,was the best.In addition,a plausible growth mechanism for the synthesis of transition metal oxide nanomaterials under the plasma condition has been proposed.At the same time,the application of zinc oxide nanorods as an antireflective layer in solar cells and a cathode material in lithium ion battery were investigated.By simulating three kinds of solar cells with different front surface treatments using PC ID software,we obtain that the zinc oxide nanorods prepared by plasma-enhanced thermal oxidation method have the best antireflective effect.By simulating a single heterojunction ZnO-Si solar cell,the photovoltaic convertion efficiency and open-circuit voltage of the solar cell have a maximum value,when the thickness of the zinc oxide is 0.1 ?m.With a farther increase of the thickness of zinc oxide,the photovoltaic convertion efficiency and open-circuit voltage gradually decrease.According to the cyclic voltammetry and constant current charge/discharge testing,we have obtained the high specific capacity of lithium ion battery base on zinc oxide nanorods grown by plasma thermal oxidation.The battery has good reversibility and stability.