| Summary: | 碩士 === 國立中正大學 === 化學暨生物化學研究所 === 100 === Core-shell nanostructures based on nano-selenium were studied in articles, followed by physical or chemical removal of core was one of routes to synthesize hollow nanostructures. Here we present several complicated nanostructures derived from the selenium nanobrush(SeNB), including SeNB@silica core-shell nanostructures, hollow silica nanobrush and its interior nano-gold deposited nanocomposite. Interior deposition was rarely mentioned, therefore the design of selective reaction inside the shell was also demonstrated.
Our research could be divided into two parts, in first part, selective removal of selenium is achieved and forming the new nanocomposite with SiO2 branches and Selenium trunk. Base on the different melting point of branches and trunk, heat removal and electron beam(E-beam) pretreatment are adopted as the strategy to remove selenium in the branches. Moreover, the electron beam effect on the silica and selenium is also discussed. The result shows that by the heating process, branches in the SeNB structure can be selectively removed(~140°C), selenium core can also be nearly complete removed under similar process(~220°C). The illumination of E-beam is found to cause the density increase of silica and melting point depression of selenium.
Second part was the synthesis of SeNB derivatives, including SeNB@SiO2, SeNB@TiO2, hollow SiO2-NB and its nano-gold deposited nanocomposite. By the using of SeNB as chemical template, coating was formed throw sol-gel process and the shell thickness can be controlled in two dimension(~6 nm and 19 nm) . Hollow SiO2-NB is accomplished by heating the SeNB@SiO2 core-shell nanostructure to remove selenium core. In addition, the demonstration of interior nano-gold deposition was also presented. The mercapto group inside the silica shell provided a selective reaction to gold ion which shows the possibility for further reaction in the future. The gold nanoparticles(8~11 nm) are formed and found to adsorb inside the hollow SiO2-NB.
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