Research Project – Emiel Hensen/Jan P. Hofmann/Giulia Spezzati
In the current situation of dwindling oil reserves, natural gas can be considered a valid alternative. While methane yields the lowest CO2 production per unit of produced energy among all the other fuels, it also has an alarming global warming potential. Its oxidation should therefore be led with high conversions, at low temperatures and with the lowest possible amount of harmful emissions.There is evidence in literature of high activity in methane oxidation displayed by palladium nanoparticles supported on cerium dioxide . CeO2 is a well-known reducible oxide that is able to stabilize noble metal nanoparticles and to take an active role in the catalysis by supplying oxygen atoms via the Mars-van Krevelen mechanism.In this project, we aim at a surface science approach in the study of these systems.
Different CeO2 nanoshapes, such as nanorods, nanocubes, nanooctahedra expose different surface terminations.Recent studies by our group point out that CeO2 nanorods expose (111) surfaces, while nanocubes expose (100) surfaces . Nanorods are also known to expose more surface defects and authors point out that they should have a direct effect on the overall catalytic performance .Hydrothermal treatment is known to be a valid pathway to obtain well-defined nanostructures. Specific CeO2 nanostructures are then selected and Pd is deposited on them in different percentages. Pd has proved to be very active in many oxidation reactions . There is still debate in literature on the nature of the active phase, and on the oxidation state of Pd nanoparticles during oxidation reactions.
A thorough characterization procedure is performed, and the following techniques are used:
- N2 adsorption
- n-situ Raman spectroscopy
- FTIR spectroscopy
Relying on the information gained via characterization, selected samples will be tested in CO and CH4 oxidation.
Our group benefits of the use of a high-throughput setup, with ten parallel microflow reactors, that can run a wide array of gas-phase reactions in a short time and is therefore able to provide a fast screening of catalytic activity.
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