Ultra-Fine Pt Entities on High-Index CeO ₂ (112) Facet Significantly Boosting Low Temperature Water–Gas Shift Reaction

In this study, two tactics were employed to develop a very efficient and durable Pt-based catalyst for low-temperature water gas shift (WGS) reaction. First, through facet engineering of CeO2, the dominantly exposed (112)/(110) facets of the oxygen-deficient CeO2 hexagonal prism (CeO2–HP) were established. Second, the Pt single atoms (SAs) and Pt fine clusters (FCs) were anchored to CeO2–HP(112)/(110) with the Ptδ+–Ov–Ce3+ and Pt2+–O2––Ce4+ interfacial sites, verified by AC-HAADF-STEM and XAFS measurements. The as-obtained 0.10Pt/CeO2–HP achieved a CO conversion rate of 12.63 mmolCO gPt–1 s–1 and a TOF as high as 2.46 s–1 at 250 °C, 2.6-fold that of benchmark Pt/Fe-0.01 SAC at 300 °C (0.93 s–1). The exposed CeO2{112} facets constitute abundant oxygen vacancies and an enhanced Pt dispersion. In-situ FTIR study demonstrated the synergetic effect between the Ptδ+–Ov–Ce3+ and Pt2+–O2––Ce4+ interfacial sites which modulates the competitive adsorption of CO and H2O. The DFT simulations revealed that the high density of oxygen vacancy over CeO2–HP(112) boosts H2O dissociation, causing a substantial enhancement in catalytic performance and a variation in the reaction route. This work provides in-depth insights into how the well-controllably assembled interfacial structure functions electronically and is structurally efficient for the target reaction.