CO2-Assisted Dehydrogenation of Propane by Atomically Dispersed Pt on MXenes

The catalytic mechanism and performance of MXene-supported atomically dispersed Pt (Pt1@MXene) in CO2-assisted propane oxidative dehydrogenation (CO2-ODHP) was evaluated by density functional theory (DFT) calculations and microkinetic simulations. The Pt single atom (Pt SA) site can promote the cleavage of two C–H bonds in propane to yield propylene via direct dehydrogenation of propane (DDHP), whereas the Pt–MXene interface facilitates the cleavage of the C–O bond in CO2 and the hydrogenation of O* to H2O via the reverse water gas shift (RWGS). Degree of rate control and Brönsted–Evans–Polanyi (BEP) correlation analyses revealed that the binding strength of Pt toward C3H7* and that of MXene toward O* determined the DDHP and RWGS activities, respectively. The DDHP activity is also highly correlated with the d-band center of the Pt SA and the work function of the Pt1@MXene surface. Microkinetic simulations showed that the Pt SA anchored on Mo2CO2 and W2CO2 possessed superior DDHP activity than the Pt(111) surface, although only Pt1@Mo2CO2 presented high activities in both DDHP and RWGS. Furthermore, the high energy barriers of deep dehydrogenations and C–C cracking of C3 derivatives over Pt1@Mo2CO2 evidenced its high anticoking ability. These predictions suggest Pt1@Mo2CO2 as a promising CO2-ODHP catalyst.