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.