Atmosphere-induced distinct Co speciations in Co/SiBEA zeolite for governing reactive stability of propane dehydrogenation

Cobalt-catalyzed propane dehydrogenation (PDH) has demonstrated considerable potential to surpass commercial Pt- and Cr-based catalysts, while achieving a balance between reactivity and stability remains challenge due to fickle Co speciations. Herein, two Co/SiBEA zeolite catalysts were designed under H 2 and Air atmosphere using dealuminated SiBEA as the support and cobalt(II) acetylacetonate as the precursor. The H 2 -derived catalyst featured the high-polymeric CoO x species onto the surface, delivering a high propylene space–time-yield (STY) of 228.9 kgC 3 H 6 ·kg Co −1 ·h −1 , but deactivated rapidly (k d  = 0.175 h −1 ). In contrast, the Air-treated catalyst yielded low-polymeric CoO x clusters confined into zeolite channels, exhibiting remarkable stability (k d  = 0.013 h −1 ) with a moderate STY of 156.9 kgC 3 H 6 ·kg Co −1 ·h −1 . Moreover, the catalyst maintained relatively stable operation for 50 h at 550 °C. Mechanistic studies further revealed that the high-polymeric CoO x species promoted hydrocarbon hydrogenolysis via Co-H phase, accelerating coke deposition, whereas the confined CoO x clusters effectively suppressed the formation of aromatic carbon precursors and facilitated propylene desorption. These findings offer a guideline for designing highly active and stable Co-based PDH catalysts.