Sökning: "porous oxides"

Visar resultat 6 - 10 av 35 avhandlingar innehållade orden porous oxides.

1. 6. Mesoporous transition metal oxides for oxygen electrocatalysis in energy conversion technologies

   Författare :Zhixing Wu; Emma Björk; Magnus Odén; Mikhail Vagin; Freddy Kleitz; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Electrocatalysis, the foundation of electrical to chemical energy transformation, enables the mitigation of the electrical energy losses during reactions and the control of selectivity of the process to certain chemical products. The slow rate and the multi-step complexity of oxygen-associated reactions, namely oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), motivate the use of platinum group metals (PGM) catalysts, which significantly increase the price of the technologies due to the cost and scarcity of PGM-based materials. LÄS MER

3. 7. Interactions between iron oxides and the additives olivine, quartzite and calcite in magnetite pellets

   Författare :Pär Semberg; Abdel-Hady Abdel-Hady El-Geassy; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Process Metallurgy; Processmetallurgi;

   Sammanfattning : In the present study, magnetite pellets with the additives olivine, calcite and quartzite were isothermally reduced in a tubular furnace to study the interaction between iron oxides and the additives. Exaggerated amounts of additives were used in order to enable analyses of phases that do not otherwise occur in sufficient amounts for X-ray diffraction and EDS-analyses. LÄS MER

4. 8. Interactions between iron oxides and the additives quartzite, calcite and olivine in magnetite-based pellets

   Författare :Pär Semberg; Lawrence Hooey; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Process Metallurgy; Processmetallurgi;

   Sammanfattning : In the present study, magnetite pellets with large amounts of the additives olivine, calcite and quartzite were isothermally reduced in a tubular furnace to study the interaction between iron oxides and the additives. A first attempt at using exaggerated amounts of additives was made in order to enable analyses of phases that do not otherwise occur in sufficient amounts for Xray diffraction and EDS-analyses. LÄS MER

5. 9. The effect of surface steps and oxides on the catalytic activity on model Pd and Rh catalysts

   Författare :Chu Zhang; Synkrotronljusfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Surface X-ray diffraction SXRD ; X-ray photonelectron spectroscopy; Catalytic activity; Oxide; Single Crystal surface; surface structure; vicinal surface; CO oxidation; stepped surface; Fysicumarkivet A:2018:Zhang;

   Sammanfattning : A catalyst is a substance that can speed up the rate of a chemical reaction without itself being consumed. Catalysts are crucial for chemical production industries, where about 90% of all chemicals are produced using catalysts. LÄS MER

7. 10. Screening of oxygen-carrier particles based on iron-, manganese-, copper- and nickel oxides for use in chemical-looping technologies

   Författare :Marcus Johansson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Oxygen Carrier; Carbon Dioxide Capture; Chemical-Looping Combustion; Chemical-Looping Reforming; Nickel Oxide; Iron Oxide; Copper Oxide; Manganese Oxide;

   Sammanfattning : Capture and storage of carbon dioxide from combustion will likely be used in the future as a method of reducing emissions of greenhouse gases and thus be part of the overall strategy to stabilize the atmospheric levels of CO2. Chemical-looping combustion is a method of combustion where CO2 is inherently separated from the non-condensable components in the flue gas without the need for an energy intensive air separation unit. LÄS MER