Enhanced Stability of Pt-Co Catalysts Supported on Zeolite Nanosponges for Propane Dehydrogenation

초록

Pt and Co supported on Al2O3, Na+-free SiO2, mesoporous zeolite (MZ-Na+), and Na+-free MZ (MZ-OH) were prepared and investigated for propane dehydrogenation efficacy. These catalysts were characterized using XRD, STEM, CO-FTIR, H2-TPR, and XPS. Of these catalysts, Pt-Co supported on MZ-Na+ and Al2O3 showed low activity and poor stability for propane dehydrogenation (PDH). On the other hand, Pt-Co supported on Na+-free SiO2 or MZ-OH exhibited much greater activity and stability. This high catalytic performance was attributed to the formation of a high degree of alloying between Pt and Co, possibly facilitated by silanol groups. After optimizing cobalt content and catalyst reduction temperature, it was found that 1 wt% Pt-0.8 wt% Co supported on MZ-OH exhibited the best activity with a propane conversion of 64.4 % and propylene selectivity of 76.5 % that remained stable over 24 h on-stream. The correlation between catalyst characterization and PDH results showed that the existence of metallic cobalt on the catalyst surface facilitated coke deposition in the form of CoCx and poor catalyst stability.

키워드