A research team led by Prof. SHEN Wenjie from the State key laboratory of Catalysis of the Dalian Institute of Chemical Physics (DICP) of the Chinese academy of sciences, in collaboration with Prof. LIU Jingyue from Arizona State University, identified the key role of the geometrical structure of the Au-Fe2O3 interfaces in CO oxidation. Their findings were published in Angew. Chem. Int. Ed..
Geometrical interfacial structure of Au-Fe2O3 catalyst. (Image by WANG Ning)
Gold nanoparticles (NPs), dispersed on reducible metal oxides, are frequently reported to be highly active for low-temperature oxidation of CO, showing a prominent size effect. Au NPs smaller than 3 nm are highly active while Au NPs larger than 5 nm are nearly inert. However, the chemical nature of the size-dependence remains controversial.
The researchers investigated the atomic arrangement of the perimeter gold atoms at the Au-Fe2O3 interfaces by tuning the size of Au NPs in the range of 2-5 nm, using aberration corrected scanning transmission electron microscopy.
They found that the activity for CO oxidation on Au/Fe2O3 catalysts was intimately associated with the geometrical structure of the interfacial perimeter Au atoms. For smaller gold particles, the perimeter gold atoms possessed a low-coordinated environment and thus showed a much higher intrinsic activity.
This result extends the fundamental understanding of the size effect in nanocatalysis and provides a promising strategy for tuning the metal-oxide interactions.
The research was supported by National Natural Science Foundation of China. (Text by WANG Ning)