Physicochemical Stabilization of Pt against Sintering for a Dehydrogenation Catalyst with High Activity, Selectivity, and Durability

Abstract

Suppressing irreversible catalyst deactivation is critical in heterogeneous catalysis. In particular, deactivation via sintering of active sites is a significant issue for reactions involving harsh reaction/regeneration conditions. In this work, we developed a PtGa/gamma-Al2O3 alkane dehydrogenation catalyst with exceptionally high activity, selectivity, and long-term stability by markedly suppressing Pt sintering under harsh conditions (reaction/regeneration at >823 K). To stabilize Pt, physical and chemical stabilization strategies were synergistically combined. For the former, Pt was introduced during the synthesis of gamma-Al2O3 via sol gel chemistry, which can increase the interfacial contact between Pt and gamma-Al2O3 due to the partial entrapment of Pt in gamma-Al2O3. For the latter, atomically dispersed Ce was doped on gamma-Al2O3, which can stabilize Pt via strong Pt-O-Ce interactions. Because of effective Pt stabilization, the catalyst showed remarkably steady activity and selectivity behaviors over the repeated reaction cycles, although the catalyst is regenerated via simple oxidation rather than industrially used oxychlorination. The Pt stabilization strategies reported in this work can be applied to other metal-catalyzed reactions that involve severe reaction/regeneration conditions.