INVESTIGATION OF THE STRUCTURAL STABILITY OF COBALT-CONTAINING ALPO-44 MICROPOROUS MATERIALS

Using the recently developed combined XRD/EXAFS technique to investigate the structural changes which occur during the calcination of Co-substituted microporous aluminophosphates, we have found significant differences between the structural stability of CoAPO-44 and the Si-substituted variant of this material which is stable at the catalytic activation temperatures. The long-range and short-range order of the templated, open-structure cobalt phosphate, known as DAF-2, was also studied. Our analysis is assisted by the availability of precise information on the variation of the thermal parameters with temperature for tetrahedrally coordinated Co.