(576c) Oxidative Dehydrogenation As a Platform for Fundamental Studies in Supported Oxides and a Playground for Tandem Catalysis
Oxidative dehydrogenation has been the subject of many academic studies in catalysis. However, it has yet to be commercialized due to intrinsic challenges in achieving high selectivity at high conversion for products that have allylic H atoms, like propylene or cyclohexene. Within these limitations, ODH is an excellent probe reaction for understanding fundamental structure-activity relationships in supported oxides. To this point, we will discuss our studies of cyclohexane ODH in supported copper oxide materials, including the important roles of surface density and support Lewis acidity. These insights are translatable to other systems of selective oxidation, including for copper oxides. Alternately, if one does not wish to obey the constraints of C-H bond strengths, ODH is amenable to strategies that decompose the reaction into two tandem steps of dehydrogenation and selective hydrogen combustion. In that light, we will discuss our recent work on tandem indium oxide - Pt/alumina catalysts for ODH-like chemistry to propylene, which can operate beyond the propane dehydrogenation equilibrium. Here, the critical role appears to be tight kinetic coupling between the two components, since neither is an effective catalyst on their own.