Ethane Dehydrogenation to Ethylene: Engineering the Surface Structure of Pt-Based Alloy Catalysts to Tune the Catalytic Performance

To improve anticoking performance and present high ethylene selectivity and activity in ethane dehydrogenation, 48 PtM (M = Cu, Ag, and Au) catalysts with four types of surface structures were engineered and evaluated by performing DFT calculations and kMC simulations. Our results show that the PtxMy intermetallic compound (IMC) catalysts with Pt and M atoms exposed together have lower C2H4(g) formation activity caused by surface electronic and geometrical properties, while they exhibit better anticoking capability due to few available active sites. The catalysts PtnL@PtxMy, PtnL@M, and Pt1L-Msub with the pure Pt shell exhibit higher C2H4(g) formation activity and different coking resistances due to more available active sites, which are closely related to the surface electronic properties. Interestingly, the electronic properties of PtxMy IMC catalysts are mainly reflected by the Bader charge of surface Pt atoms; however, those of PtnL@PtxMy, PtnL@M, and Pt1L-Msub catalysts are reflected by the d-band center of surface Pt atoms. Pt2L@PtCu catalyst with the moderate location of the d-band center is screened out as the most promising ethane dehydrogenation catalyst with the most suitable reaction conditions of 873.15 K and 1:8 partial pressure ratio of H2(g) to C2H6(g), and it has comparable C2H4(g) formation activity and stronger anticoking ability compared with other previously reported Pt-based catalysts in experiments. Through the rational surface structure design of Pt-based core–shell alloy catalysts and the precise regulation of the ligand and strain effects, catalysts with practical application potential and catalytic performance could be obtained. This work can provide a reference for the design of other alloy catalysts in alkane dehydrogenation.