Role of Nanostructured Dual-Oxide Supports in Enhanced Catalytic Activity: Theory of CO Oxidation OverAu/IrO2/TiO2

The synergetic effect in multicomponent catalysts is a topic of profound industrial importance and intense academic interest. On a newly identified multicomponent catalyst, $\mathrm{A}\mathrm{u}/\mathrm{I}\mathrm{r}{\mathrm{O}}_2/\mathrm{T}\mathrm{i}{\mathrm{O}}_2$, first-principles density-functional theory is analyzed to clarify the outstanding catalytic activity of the system for oxidative reactions at high temperatures. By comparing CO oxidation on interfaces and single-component surfaces, it is revealed that a high dispersion of a more active oxide ($\mathrm{I}\mathrm{r}{\mathrm{O}}_2$), on a more inert oxide ($\mathrm{T}\mathrm{i}{\mathrm{O}}_2$) is the key. It preserves the sintering resistance of Au supported on less active oxides, while at the same time promoting oxidative reactions that occur at the Au/active-oxide interface.