Highly efficient catalytic propane dehydrogenation driven by MFI zeolite defect sites

Abstract

Propane dehydrogenation (PDH) is a critical technology for propylene production, yet overcoming the trade-off between activity and stability remains a major challenge. Here, we engineer a robust Pt@Sn-MFI catalyst with a wormhole-type structure, featuring highly dispersed Pt clusters robustly anchored by open sites in Sn-MFI, i.e., [SiO]3 − Sn−O−Ptn, complemented by abundant zeolite defects (i.e., Si-OH) in the proximity. This architecture enables a near-thermodynamic equilibrium conversion and a propylene selectivity of ≥98.5%, with the high apparent forward rate coefficient of 1064.5 molC3H6 gPt−1h−1bar−1 and stability for at least 120 h without requiring H2 or CO2 co-feeding. Comprehensive characterization, isotope-labeling experiments and theoretical calculations reveal a plausible hydroxy-assisted PDH reaction pathway, wherein the synergy between Pt sites and neighboring hydroxyl groups (i.e., zeolite defects) significantly reduces the energy barrier for H2 formation via the combination of H in propane adsorbed on Pt sites with H in hydroxyl groups, thereby promoting the PDH process.