Revealing fundamentals affecting activity and product selectivity in non-oxidative propane dehydrogenation over bare Al2O3

Abstract

A detailed study was carried out to elucidate the factors affecting the activity and, particularly, selectivity of bare Al₂O₃ in the non-oxidative propane dehydrogenation (PDH) to propene under industrially relevant conditions. A series of samples were synthesized by a precipitation method upon varying the ratio of OH⁻/Al³⁺ in the solution. This ratio was established to affect the ability of Al₂O₃ to form aluminium cations with lower coordination (Al_cus) than regular surface Al³⁺ sites. Such defective sites show higher activity for propene formation and lower ability for coke formation. In addition to the preparation method, the kind of reducing agent for Al₂O₃ is decisive for creation of the desired defects, with CO showing higher reactivity owing to its ability to react with surface OH groups.