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

Abstract

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.