CoO x /Silicalite‐1 Tailored by Calcining Atmosphere for Oxidative Dehydrogenation of Propane With CO ₂

The relatively richer reservoir and reasonable performance in activating C─H bonds make cobalt a very competitive catalyst for the oxidative dehydrogenation of propane with carbon dioxide (CO 2 ‐ODP). However, the catalytic nature of different cobalt species is ambiguous, and the development of active and selective Co‐based CO 2 ‐ODP catalysts are at the very early stage. In this study, Co species on CoO x /Silicalite‐1 catalysts are regulated by calcining the catalyst precursor at 500°C under Ar, Air, and H 2 atmospheres, respectively. Characterization results reveal that the proportion of Co 3 O 4 spinel, metallic Co, and tetrahedrally coordinated Co 2+ species (Td‐Co 2+ ) is easily altered by changing the calcining atmosphere. Moreover, Td‐Co 2+ is revealed to be the active site for CO 2 ‐ODP while Co 0 is active for side reactions such as cracking and reforming. As a result of the richest Td‐Co 2+ and diminished Co 0 over the CoO x /Silicalite‐1 catalyst calcined in Ar, the highest CO 2 ‐ODP performance is achieved with a propylene space‐time yield of 15.88 mmol·g cat −1 ·h −1 . Besides acting as a mild oxidant, the additional functions of CO 2 are to retard the reduction of Td‐Co 2+ and to reduce the coke accumulation via the reverse Boudouard reaction during CO 2 ‐ODP. These understandings are important guides for optimizing with more efficient Co‐based CO 2 ‐ODP catalyst.