Ytreaktionsavbildning vid nära omgivande tryck
- Harding, Daniel
- Start- och slutdatum
- Beviljat belopp
- 8 000 000 kr
- Förvaltande organisation
- KTH - Royal Institute of Technology
- Materialvetenskap och materialteknologier
The main goal of the project is to develop novel instrumentation for the study of reaction dynamics and kinetics on catalytic surfaces. The idea is based on the use of ion imaging detection for surface scattering, which enables the measurement of real-time kinetics for reactions on the surface. The combination of kinetic and dynamic information simplifies experimental determination of reaction mechanisms and barriers. The possibilities offered by imaging detection for surface processes will be further extended by making it possible to study reactions at higher pressure, of the order of 1 millibar, where interaction with gas molecules can lead to the formation of metastable surfaces with new properties. This will be achieved by using sophisticated electric fields to focus ions through a differential pumping region, allowing reactions to take place at high pressure while the sensitive detector is maintained at high vacuum. The project will be split into three phases - design and construction, commissioning and testing, and first science runs. Each phase is envisaged to take approximately one year. The project will lead to the development of a new instrument of use to both academic and industrial scientists and new insight into reactions on surfaces.
Many important chemical reactions occur at the interfaces where two materials meet. Reactions of gases on solid surfaces are important both in nature and in industry. Reactions occurring on ice crystals in clouds lead to the destruction of ozone in the atmosphere. Gas—surface reactions also play important roles in pollution control, removing poisonous pollutants in car catalytic converters, and in many of the catalytic reactions that are used for the industrial production of medicines, fuels and fertilizers. The catalysts speed up the desired reactions by providing a more favorable way for the reaction to occur. Typically, the catalysts are made of particles of precious metals, often platinum. The use of precious metals makes catalysts expensive but, despite the costs, it is estimated that 90% of chemical products use catalytic steps at some stage during manufacturing. Because these reactions are so widely used improving the catalysts is an important to step towards a sustainable future. There are a number of ways in which catalysts might be made better, from reducing the energy needed to drive the reaction, to making the catalyst longer lived and more resistant to poisons, and developing catalysts which can be used to convert biomass into valuable products, reducing the need for oil. New catalysts are also needed which are made from cheap, readily available materials instead of the precious metals currently used. The efficiency of a catalyst depends not only on the type of material, but also on the size and shape of the active metal particles. This offers the possibility of using controlled structures of cheap materials as catalysts which could replace expensive precious metals. The effects of changing the size and shape of the catalysts is presently very poorly understood. My research aims to provide a better understanding of how catalytic surface reactions work and how the structure of the catalyst influences the reactivity. I develop and use new experimental techniques to investigate the reactions of molecules on well controlled surfaces. By changing the structure of the surface and measuring how this influences the reactions it is possible to build an understanding of how the structure is influencing the reactivity. Knowing which sites are most reactive under certain conditions then offers the possibility of designing the structures of real catalysts to make them work better under practical conditions.