Enhancing ammonia storage by tailoring zeolite doping

Examensarbete för masterexamen

Please use this identifier to cite or link to this item: https://hdl.handle.net/20.500.12380/300712
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Bibliographical item details
Type: Examensarbete för masterexamen
Title: Enhancing ammonia storage by tailoring zeolite doping
Authors: Schörling, David
Abstract: Selective catalytic reduction with NH3 as a reducing agent (NH3-SCR) is currently the most widely used technology to reduce NOx emissions from automotive diesel engines. One of the most prevalent types of catalysts for this purpose is zeolites. The technology requires storage of NH3 in the zeolites over a large temperature range. NH3 is stored by adsorption to H+ Brønsted acid sites and other counter ions. In this thesis, adsorption of NH3 in the zeolites CHA, BEA and MFI and the zeolite like structure AlPO have been investigated using density functional theory (DFT). In all cases, the effect of doping the zeolite framework was explored. Calculations were performed for four different dopant atoms and the counter ions H+, Cu(I), Cu(II) and Cu(II) with (OH)− adsorbed. It was found that the type of dopant atom has a clear effect on the adsorption energies of NH3 on H+ and Cu(II), while the effect is less noticeable in the cases of Cu(I) and Cu(II) with (OH)− adsorbed. The type of zeolite was also found to largely influence the results. The effect of different Al dopant distributions in CHA was also explored. It was found that the relative positions of the dopant atoms have a considerable impact on the adsorption energies.
Keywords: AlPO;BEA;catalysis;CHA;Cu;DFT;Al distribution;MFI;NH3;NOx;SCR;temperature programmed desorption;zeolites
Issue Date: 2020
Publisher: Chalmers tekniska högskola / Institutionen för fysik
URI: https://hdl.handle.net/20.500.12380/300712
Collection:Examensarbeten för masterexamen // Master Theses

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