Proper aggregation of Pt is beneficial for the epoxidation of styrene by O2 over Ptx/γ-Al2O3 catalysts†

The dispersion of metal catalysts has multiple effects on catalytic performance, and higher dispersions do not necessarily imply better performance. Herein, we report the epoxidation reaction of styrene over supported platinum catalysts as an example. Compared with the Pt₁/γ-Al₂O₃ catalyst, the Pt_n/γ-Al₂O₃ catalyst with a larger Pt cluster size showed a much better performance. Combining the results of various characterizations and density functional theory calculations, Pt_n/γ-Al₂O₃ was found to be more favorable for oxygen adsorption and activation to generate singlet oxygen species, further promoting the styrene oxidation reaction to styrene oxide in terms of kinetics. In contrast the metallic center of Pt₁ in Pt₁/γ-Al₂O₃ was too small to efficiently activate the diatomic oxygen molecule. These insights provide valuable guidance for designing high-performance metal catalysts.