In situ encapsulated subnanometric CoO clusters within silicalite ‐1 zeolite for efficient propane dehydrogenation

AbstractCobalt-based catalysts are promising alternatives to replace Pt- and Cr-based catalysts for propane dehydrogenation (PDH). However, the sintering and reduction of unstable Co sites cause fast deactivation. Herein, the ultrasmall cobalt oxide clusters encapsulated within silicalite-1 zeolites (CoO@S-1) has been obtained via a ligand assistancein situ crystallization method. This CoO@S-1 catalyst exhibits an attractive propylene formation rate of 13.66  mmolC3H6·gcat−1·h−1 with selectivity of>92% and is durable during 120-h PDH reaction with five successive regeneration cycles. The high PDH activity of CoO@S-1 is assigned to the encapsulated CoO clusters are favorable for propane adsorption and can better stabilize the detached H* species from propane, leading to the lower dehydrogenation barriers than framework Co2+ cations and Co3O4 nanoparticles. Additionally, the π-binding propylene on CoO clusters can prevent the over-dehydrogenation reaction compared with the di-σ binding propylene on metallic Co, leading to the superior propylene selectivity and catalytic stability.
Source: AIChE Journal - Category: Science Authors: Tags: REACTION ENGINEERING, KINETICS AND CATALYSIS Source Type: research