Activation of Cr2O3 for propane dehydrogenation by doping with Pt single-atom promotor

Abstract

In this work, we evaluate reaction mechanism and kinetics of propane dehydrogenation (PDH) over Pt single-atom-doped Cr2O3 catalyst by combining density functional theory calculations and microkinetic analysis. Pt single-atom-doped Cr2O3 achieves superior propane conversion and propene selectivity to PtSn alloy and pristine Cr2O3 under typical operating conditions. Pt serves as a promoter to activate nearby Cr-O Lewis-Pair sites. The promotion effect of Pt single-atom on activity is attributed to the lowered energy level of conduction band minimum of nearby O Lewis-base site, enhancing its H capture ability and accordingly facilitating first step of dehydrogenation of propane. The Pt single-atom promoter also enhances propene selectivity by adjusting the Cr-O Lewis acid-base interaction with the deep dehydrogenation product, impeding deep dehydrogenation process. This work provides theoretical insights into the feasibility of atom-level dispersion Pt promoter activating CrOx-based catalysts for PDH process, and guidance for future rational design of other oxide-supported single-atom catalysts for PDH.