Research objectives and content
Preliminary experiments carried out at the host laboratory have shown that EPR of Mn(lI) is an useful tool to study the surface of amorphous silica prepared by sol-gel methods. It was found that the paramagnetic probe introduced in the sample during the first step of the synthesis occupies surface sites and its EPR spectra are sensible to the atmosphere of the system. The aim of this project is to develop this research by using other paramagnetic cations and analysing other materials. The reactions between metals supported on silica systems and molecules having Lewis acidity will be studied, in the objective of understanding the reactivity of the metal. Xe NMR,IR, XRD, EXAFS will be used too. We will compare the surfaces sites of paramagnetic metal exchanged zeolites and doped microporous silica, by Xe NMR measurements, a novel very sensitive surface technique. Accurate EPR computer simulations will also be used in the modelling of these systems.
Training content (objective, benefit and expected impact) By sol-gel methods is possible to prepare thin film and silica materials of high specific area by controlling the operating conditions. Owing to these characteristics, sol-gel is a very useful way to prepare materials for many uses, such as catalysts membranes and many applications in optical area. Links with industry / industrial relevance (22)