Influence of O2 and O3 regeneration on the metallic phase of the Pt—Re/Al2O3 catalyst Original Research Article

The influence of the regeneration with oxygen or ozone on the metallic function activity of the Pt—Re/Al2O3 catalyst prepared by catalytic reduction is studied. The interaction between Pt and Re is higher when activation is carried out by direct reduction. However, calcination at 450°C leads to a segregation of metals. The regeneration carried out with diluted O2 destroys the metallic interaction producing segregation of Pt and Re, while the regeneration with O3 at low temperature avoids such segregation to a large extent. Ozone not only burns coke off, but also modifies its burning characteristics as measured by temperature programmed oxidation technique (TPO) with 6% O2/N2. It was found that after the O3 treatment, the coke left on the catalyst burns at lower temperatures if compared to the coke without O3 treatment. Therefore, a regeneration treatment can be carried out at low temperatures by combining a first step with O3 followed by a second one with O2 at lower temperatures than those needed in conventional regeneration procedures.