Additives on the Performance of Co₂O₃/LaCoO₃ Oxygen Carrier in Ethane Chemical Looping to Ethylene

Chemical looping oxidative dehydrogenation (CL‐ODH) is a promising novel method to convert ethane into higher value‐added ethylene. In this study, perovskite‐type Co 2 O 3 /LaCoO 3 was prepared by the one‐step citric acid‐gel method and applied as an oxygen carrier in the CL‐ODH process of ethane to ethylene; moreover, the effects of CuO, ZnO, and MgO as additives were investigated. The properties of the oxygen carriers were characterized using XRD, BET, XPS, H 2 ‐TPR, O 2 ‐TPD, and EPR. Characterization results showed that the addition of additives into Co 2 O 3 /LaCoO 3 increased the amounts of surface chemisorbed oxygen and lattice oxygen. Co 2 O 3 /LaCoO 3 had a strong ability to absorb and release oxygen after adding CuO, ZnO, and MgO, respectively. The performances of the oxygen carriers for CL‐ODH of ethane to ethylene were studied at a reaction temperature of 650°C, atmospheric pressure, and GHSV of 15,000 mL/g·h in eight redox cycles. All the oxygen carriers had 100% ethane conversion, and ZnO‐Co 2 O 3 /LaCoO 3 exhibited the best ethylene selectivity of more than 70% in all the oxygen carriers. It was confirmed that lattice oxygen was mainly responsible for the selectivity of ethylene, and oxygen vacancies were conducive to the migration of lattice oxygen. Most of Zn 2+ entered into the bulk phase of Co 2 O 3 /LaCoO 3 , and formed lots of oxygen vacancies.