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

Abstract

ABSTRACT Cobalt‐based catalysts are attractive for ethane dehydrogenation owning to their high ethane activation activity. However, in the H 2 ‐rich environment generated during the reaction, cobalt species are readily reduced to metallic Co 0 , leading to coke deposition and catalyst deactivation. Here, we present a tandem strategy that integrates a CoO x /HZSM‐5 (Co/HZ) dehydrogenation catalyst with CeO 2 ‐promoted Bi 2 O 3 (CeBiO x ) as a selective H 2 oxidation oxygen carrier. Under chemical looping oxidative dehydrogenation (CL‐ODH) conditions, CeBiO x selectively oxidizes over 75% of the in‐situ generated H 2 , thereby effectively suppressing the formation of metallic Co 0 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 H 2 by CeBiO x inhibits the reduction of cobalt species to Co 0 , thereby mitigating coke formation and enhancing ethylene yield. By coupling an ethane dehydrogenation catalyst with a selective H 2 oxidation oxygen carrier, this work establishes a new paradigm for stabilizing active Co species in Co‐based ethane dehydrogenation systems and intensifying ethylene production.