Low-temperature CO oxidation properties and TEM/STEM observation of Au/γ-Fe2O3 catalysts

• Au/γ-Fe2O3 catalyst exhibits high catalytic activity for CO oxidation.
• Active site is perimeter between Au and Au/γ-Fe2O3.
• Au particles are supported with epitaxial relationships on γ-Fe2O3.
• Atomic configuration of Au/γ-Fe2O3 interface was directly observed by ABF-STEM.

Au/γ-Fe2O3 catalysts with Au nanoparticles on γ-Fe2O3 supports were prepared by the solid grinding and deposition–precipitation methods. The prepared catalysts exhibit high activity for low-temperature CO oxidation. Their catalytic activity is proportional to the total length of the perimeters of all the Au particles on the supports, indicating that the active site is located on the perimeter. The fine structure of the prepared catalysts was investigated by aberration-corrected TEM and STEM. A preferential orientation relationship was observed between Au and the γ-Fe2O3 crystals. STEM observation revealed the atomic-scale structure of the Au(1 1 1)/γ-Fe2O3(1 1 1) interface.

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