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

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 with high low-temperature activity will suffer from deactivation due to the redispersion under high-temperature lean-burn reaction conditions. Herein, two Pt/CeO 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 selective catalytic oxidation, materials with higher CN selectively catalyzing NH oxidation to N more superior, conversely materials with lower CN performing better in CO oxidation. After activation by H reduction, both formed massive Pt clusters on the CeO 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, diffuse reflectance infrared Fourier transform spectroscopy, ., it is beyond doubt that the difference in the initial states of Pt due to distinct precursors indeed determine the redispersion behavior of the reduced Pt clusters on CeO. Materials with lower CN and higher CN 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.