Abstract
This thesis deals with the study of mixed framework phosphates whose structures contain cavities or sheets which are able to host cations in insertion. These materials can be used in numerous fields, in catalysis for example. We studied more particularly A M P O systems in which A = NH4, Rb, Cs, Ba or Sr and M = Ga, In or Al. We have isolated nineteen new phases by low temperature hydrothermal synthesis and high temperature solid state synthesis, in air or sealed tube. Structural determinations have been performed by single crystals X Ray diffraction, systematically combined with powder X Ray diffraction studies and EDX analysis, and sometimes completed by electron diffraction in a TEM, infrared spectroscopy and thermogravimetric analysis. We have also tested the activity of one of these phases in selective catalytic reduction of nitrogen oxides, by mass spectroscopy and in situ and operando IR spectroscopy. The precise determination of the crystalline structures of these new phases (two of them are original) allowed us to confirm the great structural diversity of this class of compounds. Moreover, the analysis of theirs characteristics and their comparison with similar phosphates highlighted the relationships existing between the way of synthesis used, the chemical composition studied and the structures obtained. All this results led us to conceive a simple method to order those structures depending on their opening level.