Figure 7.

Different types of Pt species supported on Al₂O₃ for CO oxidation. (a) Catalytic result of the 0.2Pt/Al₂O₃-SA sample for CO oxidation and the evolution of Pt single atoms to Pt nanoparticles under CO oxidation reaction conditions. The average sizes of Pt nanoparticles at different reaction temperatures are shown in this figure. (b) Typical HAADF–STEM image of the 0.2Pt/Al₂O₃-SA sample after the CO oxidation reaction, showing the presence of Pt nanoparticles in the used catalyst. (c) Comparison of the catalytic performance of Pt/Al₂O₃ catalysts with different sizes, ranging from single atoms to clusters to nanoparticles. (d) TOF values of different Pt/Al₂O₃ catalysts in the low-temperature range (150–225 °C) for the CO oxidation reaction. The TOF in this figure was calculated based on the total Pt amount in all the Pt/Al₂O₃ samples.