Tailoring Au-CuO interfaces for enhanced activity in CO oxidation.

[Display omitted] • Strong morphology-dependent Au-CuO interactions and catalysis were observed. • Au-CuO interactions over Au-CuO/c-Cu 2 O (cubes) are stronger. • Au-CuO interfaces over Au-CuO/c-Cu 2 O are more active in CO oxidation. • A Langmuir-Hinshelwood (LH) mechanism was proceeded over Au-CuO/c-Cu 2 O. • Au-CuO/o-Cu 2 O (octahedra) involves both LH and Mars-van-Krevelen mechanisms. Tailoring metal-oxide interfaces with controllable structures are challenging due to the complexity of interfacial structures involving multiple influence factors. Herein, both Au-CuO/Cu 2 O catalysts with different Au-CuO interfaces tuned by altering original Cu 2 O morphologies were prepared via a colloid-deposition method followed by restructuring in 1 %CO/Air atmosphere at 240 °C. Strong morphology dependence on original Cu 2 O nanocrystals was observed. The Au-CuO interactions over Au-CuO/c-Cu 2 O (cubes) catalyst are stronger than those over Au-CuO/o-Cu 2 O (octahedra), resulting in less electron-rich Au species formed. Catalytic performance of different Au-CuO interfaces in CO oxidation follows an order of Au-CuO/c-Cu 2 O > Au-CuO/o-Cu 2 O. Kinetic results together with in situ DRIFTS spectra demonstrate that a Langmuir-Hinshelwood (LH) mechanism was proceeded over Au-CuO/c-Cu 2 O catalyst, whose excellent activity could arise from the fleet desorption of adsorbed surface carbonate species to produce CO 2 , while Au-CuO/o-Cu 2 O catalyzing CO oxidation was involved with both LH and Mars-van-Krevelen mechanisms. These results greatly deepen the fundamental understanding of Au-CuO interfacial catalysis in CO oxidation and broaden the concept of morphology engineering strategy in developing efficient heterogeneous catalysts. [ABSTRACT FROM AUTHOR]