Suppressing Metallic Co 0 Formation in Co‐Based Catalyst by In‐Situ Selective H 2 Oxidation for Efficient Ethane Dehydrogenation

Cobalt-based catalysts are attractive for ethane dehydrogenation owning to their high ethane activation activity. However, in the H2-rich environment generated during the reaction, cobalt species are readily reduced to metallic Co0, leading to coke deposition and catalyst deactivation. Here, we present a tandem strategy that integrates a CoOx/HZSM-5 (Co/HZ) dehydrogenation catalyst with CeO2-promoted Bi2O3 (CeBiOx) as a selective H2 oxidation oxygen carrier. Under chemical looping oxidative dehydrogenation (CL-ODH) conditions, CeBiOx selectively oxidizes over 75% of the in-situ generated H2, thereby effectively suppressing the formation of metallic Co0 in Co/HZ. As a result, an ethane conversion of 40% and an ethylene selectivity exceeding 80% are achieved at 600°C, with stable performance maintained over 100 redox cycles. Pulse reaction experiments, semi in-situ characterizations, and density functional theory (DFT) calculations collectively reveal that the selective oxidation of H2 by CeBiOx inhibits the reduction of cobalt species to Co0, thereby mitigating coke formation and enhancing ethylene yield. By coupling an ethane dehydrogenation catalyst with a selective H2 oxidation oxygen carrier, this work establishes a new paradigm for stabilizing active Co species in Co-based ethane dehydrogenation systems and intensifying ethylene production.