Catalytic decomposition of N2O using a new generation of functionalized microporous and mesoporous inorganic materials
Journal Title: Wiadomości Chemiczne - Year 2015, Vol 69, Issue 3
Abstract
In the framework of the presented doctoral thesis, different groups of a new generation of functionalized microporous and mesoporous inorganic materials were prepared. The studies included synthesis and post synthesis modification of: mesoporous silica (SBA-15) modified with metals by MDD method, hydrotalcite‑ -like materials, nanostructured Co-Ce-O systems, hierarchical materials originated from mesoporous silicas and Beta zeolite nanoparticles, mesoporous Beta zeolite obtained using mesotemplate-free method, ZSM-5 and Y zeolites calcined at different temperatures. Physicochemical properties of the obtained materials were studied by various techniques such as: low-temperature N2sorption, X-ray diffraction, TG and ICP analyzes, EPR, IR-DRIFT and UV-vis-DR spectroscopies, SEM and TEM images, X-ray photoelectron spectroscopy, NH3-TPD and H2-TPR. The obtained samples were tested as catalysts in low-temperature (250–500°C) N2O decomposition. Nitrous oxide is one of the greenhouse gases with a very long lifetime in the atmosphere (about 150 years) and high Global Warming Potential (about 310 times of GWP of CO2). Nitric acid plants are the main source of N2O emission among chemical industry and the commercial technology for reduction of this emission, fulfilling all industrial needs, is still not available. Thus, extensive studies in this area are necessary to reduce the harmful impact of N2O on the environment. All the tested catalysts were active in N2O decomposition, however the best results were achieved over nanostructured Co-Ce-X systems obtained using reverse microemulsion method and SBA-15 modified with Rh and Cu, Fe, Ti or Al by MDD method. Over the Co-Ce-X samples 100% of N2O conversion was obtained at about 400°C, while for Rh modified SBA-15 at about 450°C. It was found that Co3O4spinel (redox centers) is responsible for high activity of Co-Ce-X systems. However, activity of this catalyst was enhanced by the presence of ceria increasing the oxygen mobility on the catalyst surface.
Authors and Affiliations
Małgorzata Rutkowska
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