Synergistic Chemistry Between Supported Platinum Atoms and Nanoclusters in Hydrocarbon Oxidation

Delineating the specific role of supported metal atoms and nanoclusters as well as their synergistic effect is particularly challenging but crucial for thermal catalytic oxidation. A programmed atomic layer deposition method is herein devised for the precise synthesis of Pt single atoms and nanoclusters coexisting on the surface of CeO₂ (Pt₁-Pt_n/CeO₂) with controllable ratios and proximity, permitting a careful optimization of the distribution and relative proportions of these Pt species. The 80%Pt₁-20%Pt_n/CeO₂ catalyst with an average separation of ≈3.7 nm between single atoms and nanoclusters exhibits unprecedented performance in hydrocarbon oxidation reaction, far superior to Pt₁/CeO₂ or Pt_n/CeO₂ catalysts and outperforming all so-far-known Pt nano-catalysts, this can also be extended to Pt₁-Pt_n/TiO₂ and Pt₁-Pt_n/ZrO₂ catalysts. The intrinsic investigations reveal a synergistic dual-active-site catalytic mechanism, involving that the polarized Pt atoms enable the fast dissociation and migration of activated hydrocarbons toward the nanoclusters center to further react with the surrounding excited oxygen. The synthesis strategy and synergistic chemistry demonstrated in this work provide a generalizable platform for the future design of well-defined complex multi-competent-site catalysts for efficient thermo-catalytic oxidation reactions.