Tandem propane dehydrogenation and surface oxidation catalysts for selective propylene synthesis.

Direct propane dehydrogenation (PDH) to propylene is a desirable commercial reaction but is highly endothermic and severely limited by thermodynamic equilibrium. Oxidative routes that oxidatively remove hydrogen as water have safety and cost challenges. We couple chemical looping selective H 2 combustion and PDH with multifunctional FeVO 4 -VO x redox catalysts. Well-dispersed VO x supported on Al 2 O 3 provides dehydrogenation sites, and adjacent nanoscale FeVO 4 acts as oxygen carriers for subsequent H 2 combustion. We achieve an integral performance of 81.3% propylene selectivity at 42.7% propane conversion at 550°C for 200 chemical looping cycles for re-oxidizing FeVO 4 . Based on catalytic experiments, spectroscopic characterization, and theory calculations, we propose a hydrogen spillover-mediated coupling mechanism. The hydrogen species generated at the VO x sites migrated to adjacent FeVO 4 for combustion, which shifted PDH toward propylene. This mechanism is favored by the proximity between catalytic and combustion sites.