Effect of CO<sub>2</sub> Co-Feeding on the Stabilization of Atomically Dispersed Iron Species over MgAl<sub>2</sub>O<sub>4</sub> During Ethane Dehydrogenation Reactions
Yingbin Zheng, Junjie Li, Xinbao Zhang, Jie An, Wenjie Xin, Xiangxue Zhu, Xiujie Li
Abstract
Ethane dehydrogenation provides an opportunity for the effective utilization of shale gas and production of ethene. Up to now, it is still a great challenge to acquire a stable ethane dehydrogenation catalyst operated under high temperature and reductive atmospheres. In this study, we prepared an Fe-based catalyst supported on MgAl 2 O 4 with atomically dispersed iron species even after 6 reaction–regeneration cycles. Sheet-like morphology and spinel structure of MgAl 2 O 4 is beneficial for the high dispersion of Fe species. The iron species undergoes reduction, sintering, and detachment during the ethane dehydrogenation reaction, as evidenced by in situ High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy and quasi-in situ 57 Fe Mössbauer spectroscopy. By contrast, the introduction of CO 2 leads to a slow deactivation, where only the partial reduction of isolated Fe 3+ species to isolated Fe 2+ species was observed. And the activity could be restored by a simple O 2 treatment. The current work sheds light on the design of high-efficient dehydrogenation catalysts.