Niobium- and Tantalum-Doped Pt-Sn/Al2 O3 as Efficient Catalysts for Propane Dehydrogenation.

Abstract

The Pt-Sn/Al2 O3 catalyst has been successfully commercialized for propane dehydrogenation, but it is still highly desirable to further improve its catalytic performance for maximizing the utilization efficiency of noble metal Pt. Herein, this work demonstrates that doping Nb and Ta into Pt-Sn/Al2 O3 has great impacts on its structure, and significantly improved catalytic performances are achieved in Pt-Sn-X/Al2 O3 (X=Nb and Ta). It is found that the incorporation of Nb and Ta into Pt-Sn/Al2 O3 can promote the dispersion of Pt-Sn particles, which results in Pt-Sn clusters being highly dispersed at the surface of Al2 O3 . Moreover, the presence of Nb and Ta makes the SnOx species less reducible, and thus the Pt-Sn particles become more stable at high temperature. Systematic exploration allows to obtain the optimized Pt-Sn-Nb5.0 /Al2 O3 and Pt-Sn-Ta1.0 /Al2 O3 , and these two catalysts exhibit high initial propane conversion (above 43.8 % and 50.4 %) with propylene selectivity of above 98 %. Most importantly, they show excellent regeneration in propane dehydrogenation, and their catalytic performance can be completely restored by a simple calcination.