Ultrastable Pt/Zn-Doped-Al2O3 Catalyst for Propane Dehydrogenation

Abstract

Propane dehydrogenation (PDH) is a crucial and effective technology to produce propylene industrially and is in great demand around the globe. Silica/zeolite-supported PtZn bimetallic catalysts have been reported to exhibit long-term operation and a consecutive regeneration process at high temperatures. However, over the industrially most commonly used support Al₂O₃, PtZn bimetallic nanoparticles suffer from low stability. Herein, we develop Zn-doped Al₂O₃ (ZnAlO_x) to stabilize PtZn nanoparticles (<1 nm) for the PDH reaction, for which the structure and composition of the PtZn intermetallic nanoparticles could be controlled by tuning the ratio of Zn/Al. The optimized catalyst with Zn/Al = 1/5 (mole ratio) exhibited the most remarkable stability with an extremely low k_d value of 0.0007 h^–1 and survived 10 cycles of regeneration tests with negligible deactivation. Characterizations by HAADF-STEM, XAS, and XRD, together with in situ XPS and CO-DRIFTS, proved that the excellent performance originated from the Pt₁Zn₁ intermetallic compound formed during the reaction and the enhanced interaction between the Pt₁Zn₁ nanoparticles and the Zn-doped Al₂O₃ support.