A DFT and Microkinetic Study of Propylene Selective Oxidation on Cu 2 O(111) Surface with O 2 : Chlorinum Effect

Abstract Spin‐polarized density functional theory (DFT) +U calculation was performed to study propylene selective oxidation on Cu 2 O(111) and Cl−Cu 2 O(111) surfaces. The mechanism included two pathways: the allylic hydrogen stripping (AHS) pathway and the epoxidation pathway, and acrolein, propylene oxide (PO), propanal and acetone can be formed. The calculated results found that the C 3 H 6 * +OO * →OOMMP 2 * →PO * route can be regarded as the preferred formation route of PO on these two surfaces. On clean surface, acrolein can be regarded as the main product, then other products selectivity follows: acetone>PO>propanal. On Cl−Cu 2 O(111) surface, acrolein was also the main product, and the apparent activation energy of acrolein (1.97 eV) was approximated to the apparent activation energy of PO (2.04 eV), other products selectivity follows: PO>propanal>acetone, which means that the selectivity of PO can be improved by the effect of Cl. Microkinetic simulation confirm that PO selectivity can be elevated qualitatively, and found that OOMMP 2 * →PO 2 * +O * is the rate determining step on pure surface and C 3 H 6 * +OO * →OOMMP 2 * is the rate controlling step on the doped−Cl surface. From this work, it can be found the O−O bond in O 2 can be activated effectively by the presence of Cl, enhancing the selectivity of PO.