Search for dissertations about: "chemical composition"

Showing result 6 - 10 of 1307 swedish dissertations containing the words chemical composition.

2. 6. A tandem Catalyst for hydrogenation of CO2 to light olefins — The role of the zeolite component

   Author : Wei Di; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Brønsted acid density; MTO reaction; CO2 hydrogenation; tandem catalysts; HCPs; methanol-intermediate; pre-coking; Al distribution; light olefins; SSZ-13 zeolite;

   Abstract : The catalytic conversion of waste CO2 into light olefins offers a sustainable pathway for green chemicals production in the future. Over a tandem catalyst with the bifunctional active sites for methanol synthesis (CTM) and methanol to olefins (MTO), CO2 can be efficiently converted via intermediate methanol into a mixture of light olefins (ethylene, propene, butene). READ MORE

4. 7. Aging of Lean NOX Trap Catalysts and Hydrocarbon Trapping in Cold-Start Applications

   Author : Rasmus Jonsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES;

   Abstract : It is well known that combustion processes worldwide give rise to emissions such as nitrogen oxides (NOX), carbon monoxide (CO), hydrocarbons (HC) and particulates. For vehicles, the method for handling these emissions has been through the development of the catalytic converter. READ MORE

5. 8. Operando X-ray Absorption Spectroscopy Studies of Methane Oxidation Catalysts

   Author : Johan Nilsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; operando spectroscopy; XAS; palladium; heterogeneous catalysis; methane oxidation; XAFS;

   Abstract : Operando spectroscopy is an experimental method in catalysis that combines measurements of catalytic activity and selectivity with simultaneous in situ spectroscopic characterization of the catalyst. Since the structure and composition of the catalyst are probed under reaction conditions, the method can provide valuable information to elucidate the mechanism of the studied reaction. READ MORE

6. 9. Deactivation of SCR catalysts - Impact of sulfur and the use of biofuels

   Author : Johanna Englund; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Cu-SSZ-13; Cu-CHA; Catalyst deactivation; Activity test; DeNOx; Sulfur; NOx reduction; NH3-SCR; FAME; Emission control; HVO; Vanadia; Biofuel;

   Abstract : In a near future, limits on CO2 emissions from vehicles will be introduced, which requires development of more fuel-efficient engines and most likely a transition towards the use of more biofuels. With the implementation of biofuels several issues could arise, one being the lack of fuel standards for these new type of fuels, leading to higher concentrations of catalyst poisons compared to conventional fossil fuels. READ MORE

7. 10. Interactions of methane and carbon monoxide with platinum - Supported catalysts and chemical sensors

   Author : Elin Becker; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Periodic operation In situ spectroscopy; XAS; CO; Sensing mechanism; Low-temperature activity; XANES; Pt; Environmental catalysis; Support material; CH4; Chemical sensors;

   Abstract : This thesis aims at increasing the understanding of the interactions of methane and carbon monoxide with platinum in connection to catalysis and sensor technology for emission control. Specifically, the low-temperature oxidation of methane and carbon monoxide over supported platinum catalysts and the sensor response mechanism towards CO of platinum-based chemical field effect sensors were studied. READ MORE