Characterisation of Cu-SAPO-STA-7 using CO and NO

B. MOULIN, L. GABEROVA, P. LLEWELLYN, A. VILMONT, A. L. PICONE, P. A. WRIGHT

Sorrento

Conferencia; 16th International Zeolite Conference and 7th International Mesostructured Materials Symposium (IZC-IMMS 2010); 2010

The silicoaluminophosphates (SAPOs) belong to the class of zeotype materials, iso-structural in some cases with aluminosilicate zeolites and characterized by a milder acidity compared to that of zeolites. The substitution of phosphorus by the silicon inside of the pure AlPOs creates a negative charge which could be counter-balanced by the presence of extra-framework cations. It has been clearly established that the cations can modify the properties of the given materials and make them interesting in different fields of applications such as catalysis or adsorption.  In this study, we have investigated the silicoaluminophosphate material named SAPO-STA-7 (SAV), whose structure is defined as a fully tetrahedrally connected framework, containing two distinct channel systems each constrained by 8MR (denoted A and B). In the synthesis approach two different templates were used (the cyclam as template and TEA+ as co-template) and by their combination the structure of SAPO-STA-7 was attained. However another possibility is offered in synthesis approach by using metalled cyclam as a template which introduces Cu2+ as extra-framework cation in these materials without use of aqueous solution. By this method, a highly crystalline and porous Cu-SAPO-STA-7 material was prepared . The Rietveld refinement confirmed 4 different positions of Cu2+ inside its structure. The 1st position and its analogous 2nd position are located in the 8MR window of the A and B channels, respectively. A 3rd position is found close to the 4MR of the main A channel wall and 4th outside the D6R unit. In this work the copper sites within Cu-SAPO-STA-7 have been probed by IR (determination of the oxidation states of Cu and attribution of its different positions according to the refinement) and also adsorption microcalorimetry (strength of active site) using CO and NO as probe molecules.