Zinc Migration Mediates Isolated [PtFe3] in Zeolite for Propane Dehydrogenation

Abstract

Structural transformation under in situ reaction conditions plays a vital role in heterogeneous catalytic performance, especially caused by metal migration. However, the migration of active components often leads to irreversible structural disruption at high temperatures, which could be associated with the deactivation of catalysts. Here, we report a low-melting-point Zn migration-mediated strategy to synthesize ultrastable isolated PtFe₃ sites anchored in MFI zeolite for propane direct dehydrogenation. The optimized catalyst exhibited a superior specific activity of 36.5 mol C₃H₆ mol_Pt^–1 s^–1 with propylene selectivity above 99% at 550 °C. Moreover, the dehydrogenation activity remained stable after over 400 h on stream with a low deactivation rate constant of 0.001 h^–1 under industrial conditions at 580 °C. In situ characterizations demonstrated that Fe³⁺ species were conducive to the rearrangement in the electronic configuration of the unoccupied 5d states of Pt atoms to form electron-deficient Pt sites. This strategy could afford insights into the dynamic evolution of catalyst preparation in heterogeneous processes.