Structure–Activity Relationships in Alkane Dehydrogenation on γ-Al2O3: Site-Dependent Reactions

Abstract

A promising route to produce olefins, the building blocks for plastics and chemicals, is the nonoxidative dehydrogenation of alkanes on metal oxides, taking advantage of the Lewis acid–base surface functionalities of the oxides. However, how alkane dehydrogenation activity depends on the strength of surface acid–base site pairs is still elusive. In this work, we provide fundamental insights into the reaction mechanisms of propane dehydrogenation on different facets of γ-Al2O3 and develop structure–activity relationships, using density functional theory calculations and first-principles molecular dynamics simulations. We identified the binding energy of dissociated H2 as an activity descriptor for alkane dehydrogenation. Interestingly, a volcano relationship between catalytic activity and dissociative H2 binding energy was discovered for propane dehydrogenation, unraveling a site-dependent catalytic behavior on γ-Al2O3, with a concerted surface mechanism being energetically preferred to a sequential one on...