Search for dissertations about: "Chabazite"

Found 5 swedish dissertations containing the word Chabazite.

  2. 1. On the Character of Active Sites in Copper Exchanged Zeolites during NH3-SCR

    Author : Lin Chen; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Cu-SSZ-13; SSIE; O2-dissociation; Al-distribution; NH3-SCR; Chabazite; O2-activation;

    Abstract : Nitrogen oxides (NOx) are formed during combustion in diesel engines and one current approach to reduce NOx to N2 is selective catalytic reduction with NH3 as reducing agent (NH3-SCR). To acquire both high activity and selectivity, the active site is often atomically dispersed metal atom, so-called single-site catalysts. READ MORE

  4. 2. Partial Oxidation of Methane over Functionalised Zeolites and Zeotypes

    Author : Xueting Wang; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; FTIR; Heterogeneous catalysis; Copper boron silicate; Zeolite; Natural gas; Biogas; Green methanol; zeotype; Temperature-programmed desorption; Cu-SSZ-13; Cu-ZSM-5; In situ infrared spectroscopy;

    Abstract : Partial oxidation of methane to methanol is an industrially important process that allows natural gas and biogas to be utilised for methanol-based production of chemicals or converted to liquid methanol fuel, which make transportation more facile. In this thesis, the activity for partial oxidation of methane to methanol over copper functionalised zeolites and silica supported copper is investigated using a three-step quasi-catalytic approach including catalyst activation, methane reaction and methanol extraction by water. READ MORE

  5. 3. Dynamics and Reactivity of Cu-species in Cu-CHA for NH3-SCR

    Author : Joachim Bjerregaard; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Machine Learning Force Field; Diffusion; Cu-CHA; NH3-SCR; DFT; Sulfur Deactivation;

    Abstract : Copper exchanged chabazite (Cu-CHA) is a state-of-the-art catalyst for deNOx via ammonia assisted selective catalytic reduction (NH3-SCR) in lean burn engines, owing to its good low-temperature activity, and high hydrothermal stability. One challenge for Cu-CHA is, however, the sensitivity to sulfur species, which are present in the exhaust gas. READ MORE

  6. 4. Reaction kinetics of NH3-SCR over Cu-CHA from first principles

    Author : Yingxin Feng; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Catalysis; microkinetic modeling; density functional theory; Cu-CHA; ammonia assisted selective catalytic reduction;

    Abstract : Ammonia-assisted selective catalytic reduction (NH3-SCR) is an advanced technology to reduce nitrogen oxide (NOx) emissions from lean-burn engines. NH3 is added to the exhaust gas and reacts selectively with NOx, forming N2 and H2O. READ MORE

  7. 5. Reactions on nanostructured and microporous surfaces

    Author : Anna Clemens; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Cu-CHA; XRD; solid-state ion-exchange; materials characterisation; electron microscopy; NH3-SCR; zeolites; catalysis; nanostructured graphite; Water ice; DRIFTS; XPS; NOx reduction; Cu-SSZ-13; temperature programmed desorption; ultra-high vacuum; intercalation; UV-Vis spectroscopy;

    Abstract : Interactions between surfaces and molecules play a central role in various fields where catalysis is one example. In order to understand different surface processes, physicochemical characterisation of the surface materials and molecules is required. READ MORE