Ultrasmall Au₁₀ clusters anchored on pyramid-capped rectangular TiO₂ for olefin oxidation

Ultrasmall Au₁₀ clusters have a unique electronic structure and can act as a charge reservoir to donate electrons or accept charges. This is particularly important for catalysis, since it leads to facile charge transfer across the interface between the gold species and the oxide substrate. To determine the electronic and structural effects of Au₁₀ on the catalytic oxidation, a TiO₂ charge carrier was chosen as the substrate to anchor Au₁₀ for olefin oxidation. Au₁₀ supported on TiO₂-RP (RP = pyramid-capped columnar structure) exhibited superior catalytic activity to Au₁₀/TiO₂ nanotubes and Au₁₀/P25. In addition, the supported Au₁₀ clusters gave rise to higher activity than supported Au₂₀, Au₁₄₄ clusters, and 5 nm Au nanocrystals. The superior catalytic ability of Au₁₀/TiO₂-RP arises from the charge/discharge effect of the Au₁₀/TiO₂-RP interface, which effectively improves the formation of active oxygen species on electron-rich gold atoms at the terminal position of Au₁₀, and promotes the activation of olefin C=C bonds on the electron-deficient gold atoms of Au₁₀.