Heptane Dehydrocyclization Over Pt/KL Catalysts Doped with Barium or Lanthanum

Abstract

Several 1 wt% Pt/KL catalysts doped with different concentrations of either BaO or La2O3 were prepared by successive impregnation of a zeolite KL and then characterized by H2-O2 titration, TPR, CO–FTIR, TEM-XEDS and XPS. Catalytic activity measurements in the hydroconversion of n-heptane showed that barium highly enhances the aromatization activity of Pt/KL, the more so the higher the barium concentration. The yield to aromatics increases to a lesser degree by adding 1 wt% La, but it is little modified at higher La concentrations. The CO–FTIR results suggest that the promoter effect of barium is related to an electron enrichment of Pt produced by the BaO → Pt0 interaction which, according to the TEM–XEDS and XPS results, is more favored than the La2O3 → Pt interaction.