Surface Oxygen Vacancies as Active Sites for Nonoxidative Propane Dehydrogenation on Metal Oxide Catalysts

The catalytic activity of metal oxides in nonoxidative propane dehydrogenation (PDH) is increasingly attributed to surface oxygen vacancies (OVs). In this study, the catalytic performance of GaO x /Al 2 O 3, a typical oxide catalyst active in PDH, was compared to its ability to catalyze oxygen isotope homoexchange at room temperature, which serves as a reference method for detecting catalytically active OVs. In particular, it was demonstrated that upon pretreatment with propane or H 2 at 510 °C, the GaO x /Al 2 O 3 catalyst becomes capable of inducing 16 O 2 / 18 O 2 isotope exchange at 20 °C, which can occur only on the surface OVs formed in the previous reaction.