Modulating Lattice Oxygen in Dual-Functional Mo-V-O Mixed Oxides for Chemical Looping Oxidative Dehydrogenation

Oxygen chemistry plays a pivotal role in numerous chemical reactions. In particular, selective cleavage of C-H bonds by metal oxo species is highly desirable in dehydrogenation of light alkanes. However, high selectivity of alkene is usually hampered through consecutive oxygenation reactions in a conventional oxidative dehydrogenation (ODH) scheme. Herein, we show that dual-functional Mo-V-O mixed oxides selectively convert propane to propylene via an alternative chemical looping oxidative dehydrogenation (CL-ODH) approach. At 500 °C, we obtain 89% propylene selectivity at 36% propane conversion over 100 dehydrogenation-regeneration cycles. We attribute such high propylene yield-which exceeds that of previously reported ODH catalysts-to the involvement and precise modulation of bulk lattice oxygen via atomic-scale doping of Mo and show that increasing the binding energy of V-O bonds is critical to enhance the selectivity of propylene. This work provides the fundamental understanding of metal-oxygen chemistry and a promising strategy for alkane dehydrogenation.