Silicalite-1 Stabilizes Zn-Hydride Species for Efficient Propane Dehydrogenation

Propane dehydrogenation (PDH) is promising for producing high value-added propylene. The discovery of a more efficient, economical, and nontoxic PDH catalyst is of great importance. Herein, we found zinc hydrides (ZnH+) as the highly reactive site for PDH. In situ spectroscopy and theoretical studies reveal that ZnH+ was transformed from zinc hydroxyl (ZnOH+) sites under reductive conditions. Accordingly, the formation of ZnH+ can be controlled by adjusting the amount of zinc hydroxyl (ZnOH+) species by various additives. The optimized Cu–ZnO@S-1 consists of exclusively isolated ZnOH+ sites, which help produce more ZnH+ toward optimal PDH activity. Specifically, the catalyst enables 43% propane conversion with >88% propylene selectivity, close to the thermodynamic equilibrium. This efficient PDH performance was attributed to the electron-deficient Zn in ZnH+ that can lower the dehydrogenation barrier, and the Cu-modified ZnH+ structure favors the direct PDH pathway to further promote the formation of propylene and H2.