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

Abstract

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 Pt x M y intermetallic compound (IMC) catalysts with Pt and M atoms exposed together have lower C 2 H 4 (g) formation activity caused by surface electronic and geometrical properties, while they exhibit better anticoking capability due to few available active sites. The catalysts Pt nL @Pt x M y, Pt nL @M, and Pt 1L -M sub with the pure Pt shell exhibit higher C 2 H 4 (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 Pt x M y IMC catalysts are mainly reflected by the Bader charge of surface Pt atoms; however, those of Pt nL @Pt x M y, Pt nL @M, and Pt 1L -M sub catalysts are reflected by the d -band center of surface Pt atoms. Pt 2L @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 H 2 (g) to C 2 H 6 (g), and it has comparable C 2 H 4 (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.

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