A tandem system of Cr/HZSM-5 and bismuth-modified CeZrO2 for coupling of ethane dehydrogenation to selective H2 combustion

Ethylene production via chemical looping oxidative dehydrogenation (CL-ODH) of ethane faces a critical challenge in balancing conversion efficiency and selectivity due to competing oxygen species requirements. Here, we present a bifunctional composite catalyst (CrH/BiCZ) by physically integrating a Cr-HZSM5 (Cr-H) dehydrogenation (DH) catalyst with a Bi 2 O 3 -Ce 0.4 Zr 0.6 O 2 (Bi-CZ) selective hydrogen combustion (SHC) catalyst. This tandem system decouples ethane activation and hydrogen combustion, promoting the DH process of ethane through the in situ hydrogen combustion of the SHC catalyst. The Ce-Zr solid solution in Bi-CZ acts as an oxygen reservoir, enabling complete H 2 combustion within 3 min and suppressing carbon deposition. This rapid hydrogen combustion shifts the reaction equilibrium towards ethylene production. At 650 °C, the optimized CrH/BiCZ catalyst achieves 84.1 % ethylene selectivity at 43.0 % ethane conversion, and maintains exceptional stability over 36 redox cycles. This work establishes a scalable chemical looping strategy for efficient ethylene synthesis.