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Insights into the Construction of Robust Pt Clusters with Satisfactory Stability on CeO 2 for the Catalytic Oxidation of CO.

Peng YangChaoyi LuoWei TanQinglong LiuShaoxiong ZhangSong HongFei GaoLin Dong
Published in: ACS applied materials & interfaces (2024)
Improving the efficiency of platinum group metals (Pt, Pd, Rh, etc.) in catalytic oxidation reactions remains an urgent topic. The conflict between the low-temperature activity and high-temperature stability of noble metals can hardly reach a consensus. For instance, Pt cluster catalysts supported on CeO 2 with high low-temperature activity will suffer from deactivation due to the redispersion under high-temperature lean-burn reaction conditions. Herein, two Pt 1 /CeO 2 prepared by the incipient wetness impregnation method using different Pt precursors possessed varied Pt-O and Pt-O-Ce coordination numbers (CNs). They showed various priorities in CO oxidation versus NH 3 selective catalytic oxidation, materials with higher CN Pt-O-Ce selectively catalyzing NH 3 oxidation to N 2 more superior, conversely materials with lower CN Pt-O-Ce performing better in CO oxidation. After activation by H 2 reduction, both formed massive Pt clusters on the CeO 2 surface but showed drastically distinct stability in lean-burn CO oxidation reactions. By summarizing the experimental results of high-angle annular dark-field scanning transmission electron microscopy, X-ray absorption spectroscopy, Raman spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy, etc ., it is beyond doubt that the difference in the initial states of Pt 1 due to distinct precursors indeed determine the redispersion behavior of the reduced Pt clusters on CeO 2 . Materials with lower CN Pt-O-Ce and higher CN Pt-O are more likely to form robust Pt clusters, as they are not conducive to Pt anchoring, thus restricting the reversible structural evolution occurring under lean-burn CO oxidation and reductive conditions. This approach serves as a guide for the convenient and efficient construction and exploration of robust Pt cluster catalysts.
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