| Summary: | 碩士 === 國立中興大學 === 環境工程學系所 === 104 === Metal Organic Frameworks (MOFs) represents one of the most versatile nanomaterials nowadays. MOF-derived materials also become diversification. In this study, we develop a one-step carbonization process to prepare carbon-supported cobalt material, named as Magnetic Carbon/Cobalt Composite (MCCC), derived from a cobalt-based Metal Organic Framework (ZIF-67). The detailed characterization of MCCC is analyzed by FE-SEM, TEM, XRD and XPS. The magnetism, porosity and cobalt content of MCCC make it exhibit good controllability and catalytic ability.
In the first application, MCCC is used to catalyze NaBH4 hydrolysis for H2 production. While nano-scale cobalt catalyst is recognized as one of the most efficient catalysts for H2 production from NaBH4 hydrolysis, it tends to aggregate and decreases the catalytic activities. The cobalt is uniform loaded on MCCC that can avoid the aggregation. Effects of catalyst loading, temperature and sodium hydroxide concentration were thoroughly examined. Under alkaline conditions, the activation energy of the hydrolysis is 28.45 kJ mol-1. MCCC shows a superior catalytic capability with a low activation energy. Finally, an experiment of providing NaBH4 continuously is used to test the stability of MCCC catalyzing NaBH4 hydrolysis. MCCC shows efficient recyclability to hydrolyze NaBH4 over 5 cycles without rinsing. Based on the above experiments, we know that MCCC is an effective and practical heterogeneous catalyst for H2 production from hydrolyzing of NaBH4.
The second application, MCCC is used to activate peroxymonosulfate (commercial name : Oxone) for the decolorization of rhodamine B. Normally, the oxidation reaction with Oxone activated by transition metal is faster than by Oxone alone. For the investigation of parameters, this MCCC-activated Oxone process is found to be the most effective when the concentration of MCCC is 50 mg L-1 and the concentration of Oxone is 250 mg L-1; the higher temperatures improved the decolorization efficiency significantly; alkaline solution will be harmful to the generation of sulfate radical and weaken the oxidation reaction; UV photocatalyzation and ultrasonication are both found to enhance the MCCC-activated Oxone process. The recyclability test demonstrated that MCCC can be continuously used with effective catalytic activity. Above these features enable MCCC to be an effective catalyst for the oxone oxidation process.
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