Propane Dehydrogenation on Single-Site [PtZn4] Intermetallic Catalysts

Propane dehydrogenation (PDH) is a commercial propylene production technology that has received much attention, but high reaction temperatures result in a decrease of propylene selectivity and catalyst stability. This paper describes a single-site [PtZn4] catalyst by assembling atomically ordered intermetallic alloy (IMA) as a selective and ultrastable PDH catalyst. The catalyst enables more than 95% of propylene selectivity from 520 degrees C to 620 degrees C. No obvious deactivation is observed within the 160-h test, superior to PtSn/Al2O3 and state-of-the-art Pt-based catalysts. Based on in situ X-ray absorption fine structure, X-ray photoelectron spectroscopy measurements, and density functional theory calculations, we reveal that the surface [PtZn4] ensembles in PtZn IMAs serve as the key active site structures, wherein the geometry-isolated and electron-rich Pt-1 site in [PtZn4] ensembles readily promotes the first and second C-H cleavage of propane but inhibits further dehydrogenation of surface-bounded propylene. This significantly improves the selectivity and stability by prohibiting coke side reactions.

Automated summary

The single-site [PtZn4] catalyst developed in this study exhibits high selectivity and ultra-stability, achieving over 95% propylene selectivity in a high temperature range, with no obvious deactivation observed during long-term testing. The surface [PtZn4] ensembles in PtZn IMAs serve as key active site structures, promoting the C-H cleavage of propane while inhibiting further dehydrogenation of surface-bounded propylene, thereby improving selectivity and stability.