Origin of Carbon Monoxide Formation in the Oxidative Dehydrogenation of Propane Using Carbon Dioxide

The oxidative dehydrogenation of C3H8 to C3H6 using CO2 is an attractive alternative to nonoxidative propane dehydrogenation and facilitates the utilization of CO2. The activity of supported nanoparticles for this reaction has been extensively investigated, but the often-overlooked deleterious formation of CO via reforming reactions remains a challenge with these catalysts. In this paper, we investigate the origin of CO formation over supported nanoparticle catalysts and find that the support and metal both play a role in favoring the formation of either CO or C3H6. Reducible supports are associated with higher activity and increased CO formation, but nonreducible supports also facilitate CO formation. Supported Pt catalysts were more selective toward C3H6 than Pd analogues, but both catalysts favored coke formation. These findings highlight the need for careful catalyst design in supported nanoparticle catalysts for the oxidative dehydrogenation of propane using carbon dioxide, particularly with respect to tuning catalyst selectivity.