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 520C to 620C. 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 Pt1 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.
Sai Chen, Zhi-Jian Zhao, Rentao Mu, Xin Chang, Jun Luo, Stephen C. Purdy, Jeremy Kropf, Guodong Sun, Chunlei Pei, Jeffrey T. Miller, Xiaohong Zhou, Evgeny Vovk, Yong Yang, and Jinlong Gong*, "Propane Dehydrogenation on Single-site [PtZn] Intermetallic Catalysts," Chem 2021, 7, 387-405.