Highly Dispersed and Ultrafine Cobalt(II) Oxide Nanoparticles Stabilized on Hollow Silicalite-1 Zeolite for Enhanced Propane Dehydrogenation

Recently, cobalt-based heterogeneous catalysts have become a promising avenue in the propane dehydrogenation (PDH) process, due to their remarkable hydrocarbon activation ability and economic viability. However, achieving highly efficient and stable catalytically active Co species for the PDH reaction continues to pose a significant challenge. Herein, we constructed a hollow silicalite-1 (S-1) zeolite architecture stabilized by a highly dispersed, uniform, and nanosized CoO catalyst (CoO@S-1) derived from the uniform S-1 zeolite precursor prepared by a microliquid-film reactor-assisted hydrothermal method. The results showed that the ultrafine CoO nanoparticles were homogeneously immobilized on the outer shell matrix and inner walls of the hollow S-1 zeolite. As-constructed CoO@S-1 catalyst achieved an impressively high propylene production rate of 1596 mmolC3H6·gCo–1·h–1 in PDH at a 1.6 h–1 propane space velocity and 600 °C. Additionally, the catalyst delivered an unprecedentedly high propylene production rate of 44.5 mmolC3H6·gcat–1·h–1 at a higher space velocity of 6.0 h–1, far surpassing those of state-of-the-art cobalt-based PDH catalysts. It was unveiled that the superior catalytic PDH efficacy of the catalyst was mainly ascribed to the formation of highly dispersed and ultrafine active CoO species stabilized on the hollow S-1 zeolite through Co–O–Si structures formed by consuming abundant skeletal silanol groups of the zeolite precursor, thereby leading to enhanced activity, propylene selectivity, and structural stability. The present study affords a promising way to construct high-performance S-1 zeolite-immobilized metal-oxide catalysts for advanced alkane dehydrogenation applications.