Niobium- and Tantalum-Doped Pt-Sn/Al 2 O 3 as Efficient Catalysts for Propane Dehydrogenation.

The Pt-Sn/Al 2 O 3 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/Al 2 O 3 has great impacts on its structure, and significantly improved catalytic performances are achieved in Pt-Sn-X/Al 2 O 3 (X=Nb and Ta). It is found that the incorporation of Nb and Ta into Pt-Sn/Al 2 O 3 can promote the dispersion of Pt-Sn particles, which results in Pt-Sn clusters being highly dispersed at the surface of Al 2 O 3 . Moreover, the presence of Nb and Ta makes the SnO x species less reducible, and thus the Pt-Sn particles become more stable at high temperature. Systematic exploration allows to obtain the optimized Pt-Sn-Nb 5.0 /Al 2 O 3 and Pt-Sn-Ta 1.0 /Al 2 O 3 , 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.