Origin of Performances of Pt/Cu Single-Atom Alloy Catalysts for Propane Dehydrogenation

The propane dehydrogenation (PDH) reaction converts cheap propane to value-added propene. Pt-based catalysts show high performance in PDH, but suffer from coke formation and deactivation. Therefore, promoter, that is, a second metal component, is required to enhance its stability. Our previous study has constructed Pt/Cu single atom alloy (SAA) catalysts and achieved high PDH selectivity and anticoke ability. However, the nature of its high performance in PDH still remains to be revealed. This paper describes the origin of catalytic performance for Pt/Cu SAA in PDH via density functional theory (DFT) calculations and kinetic Monte Carlo (kMC) simulations. We constructed a complex reaction network with 54 reversible reaction steps, including adsorption, desorption, C–H bond breaking, and C–C bond cracking processes on the Pt/Cu SAA catalyst. The high selectivity of propene has been demonstrated because of the higher occurrence of propene formation and, simultaneously, the high energy barriers for deep dehydrogenation of propene. The lower coverages of the coke species origin from the deep dehydrogenation instead of the C–C bond cracking for Pt/Cu SAA catalyst, which is different from that proposed for Pt catalyst. The simulation suggests that hydrogen (H2) cofeeding can further reduce the surface coke species. Overall, the current study provides fundamental insights into the origin of high selectivity and anticoke ability to help the design of stable and high-performance Pt-based catalysts.