Highly Stable Pt/CeO Catalyst with Embedding Structure toward Water-Gas Shift Reaction.

Strong metal-support interaction (SMSI) has been extensively studied in heterogeneous catalysis because of its significance in stabilizing active metals and tuning catalytic performance, but the origin of SMSI is not fully revealed. Herein, by using Pt/CeO as a model catalyst, we report an embedding structure at the interface between Pt and (110) plane of CeO, where Pt clusters (∼1.6 nm) are embedded into the lattice of ceria within 3-4 atomic layers. In contrast, this phenomenon is absent in the CeO(100) support. This unique geometric structure, as an effective motivator, triggers more significant electron transfer from Pt clusters to CeO(110) support accompanied by the formation of interfacial structure (Pt-O-Ce), which plays a crucial role in stabilizing Pt nanoclusters. A comprehensive investigation based on experimental studies and theoretical calculations substantiates that the interfacial sites serve as the intrinsic active center toward water-gas shift reaction (WGSR), featuring a moderate strength CO activation adsorption and largely decreased energy barrier of HO dissociation, accounting for the prominent catalytic activity of Pt/CeO(110) (a reaction rate of 15.76 mol g h and a turnover frequency value of 2.19 s at 250 °C). In addition, the Pt/CeO(110) catalyst shows a prominent durability within a 120 h time-on-stream test, far outperforming the Pt/CeO(100) one, which demonstrates the advantages of this embedding structure for improving catalyst stability.