Applied Catalysis A: General, Vol.165, No.1-2, 207-218, 1997
Influence of O-2 and O-3 regeneration on the metallic phase of the Pt-Re/Al2O3 catalyst
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 degrees C leads to a segregation of metals. The regeneration carried out with diluted O-2 destroys the metallic interaction producing segregation of Pt and Re, while the regeneration with O-3 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% O-2/N-2. It was found that after the O-3 treatment, the coke left on the catalyst burns at lower temperatures if compared to the coke without O-3 treatment. Therefore, a regeneration treatment can be carried out at low temperatures by combining a first step with O-3 followed by a second one with O-2 at lower temperatures than those needed in conventional regeneration procedures.
Keywords:TEMPERATURE-PROGRAMMED REDUCTION;SURFACE REDOX REACTIONS;PT-RE INTERACTION;REFORMING CATALYSTS;BIMETALLIC CATALYSTS;COKE;PLATINUM;RHENIUM;OXYGEN;OZONE