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Contenu archivé le 2022-12-23

Structure and chemistry of air pollutants on metal surfaces

Objectif

- To study the structure and reactivity of small pollutant molecules (CO2, NO, NO2 and SO2) over well defined metal single crystal surfaces;
- To study in particular the least active, most abundant molecule CO2, attempting to define ways to effectively activate it;
- Studies on clean surface will be compared to the partially alkali metal covered surfaces, as a function of its coverage. Other surface sensitive, nondestructive methods such as work function change measurements and optical second harmonic generation (SHG) will be employed in cases where in situ coverage changes may be crucial to extract the kinetics of intermediate formation;
- To widen the basic understanding of the surface chemistry of small molecules of ecological importance.
Expected Outcome

- Interdependence in all of these activities will be a major feature of the programme. In the first phase, the exploratory TPD, SHG work (Jerusalem) and the vibrational spectroscopy studie's using HREELS (Jülich) and RAIRS (Cambridge) will define the molecular integrity of the coadsorbed species. This information will be useful in subsequent studies of hydrogenation and catalytic activity (Jerusalem) and surface crystallography (Jülich, Cambridge). Finally, the groups will be able to compare the advantages and disadvantages of three metals - CO, Re and Ru - for these activation processes.
Different crystals will be investigated in the three laboratories. However, in order to apply complementary methods, the different crystals will be switched between the three laboratories, such that a given experimental method will not be limited to only one substrate. The project started with smooth basal planes (0001) of the three hexagonal closed packed metals Re, Ru and CO and investigate more corrugated planes like the (1010) and more inert substrates (Ag(110) later.

- The sticking probability and adsorption mechanism of CO2 on Ru(0001) and Co(0001);
- The determination of thermal dissociation probabilities over the above clean surface;
- After completion of above, the same activity and adsorption kinetic studies will be performed over alkali metal covered surfaces;
- Parallel to the adsorption-dissociation-desorption studies, the strucutre of CO2 on the clean and the modified surfaces will be determined primarily by means of LEED analysis but also with new holographic technique and X-ray photoelectron forward scattering (XPD) method;
- Application of optical SHG during the studies of the alkali covered surfaces;
- After study of the thermal activity of CO2 ,collision induced effects on the surface chemistry will be investigated;
- Studies of calorimetric adsorption heats on the clean and then modified surfaces;
- High pressure (up to 1 atmosphere) hydrogenation of CO2 over the clean and then the alkali metal covered surfaces;
- Finally, NO vs NO2 and then also SO2 will be introduced and their initial interaction with the above surfaces investigated.

Thème(s)

Data not available

Appel à propositions

Data not available

Régime de financement

CSC - Cost-sharing contracts

Coordinateur

University of Cambridge
Contribution de l’UE
Aucune donnée
Adresse
Lensfield Road
CB2 1EW Cambridge
Royaume-Uni

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Coût total
Aucune donnée

Participants (1)