Twinning in fcc lattice creates low-coordinated catalytically active sites in porous gold
- Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84511 Bratislava (Slovakia)
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan)
We describe a new mechanism for creation of catalytically active sites in porous gold. Samples of porous gold prepared by de-alloying Al{sub 2}Au exhibit a clear correlation between the catalytic reactivity towards CO oxidation and structural defects in the fcc lattice of Au. We have found that on the stepped (211) surfaces quite common twin boundary defects in the bulk structure of porous gold can form long close-packed rows of atoms with the coordination number CN = 6. DFT calculations confirm that on these low-coordinated Au sites dioxygen chemisorbs and CO oxidation can proceed via the Langmuir–Hinshelwood mechanism with the activation energy of 37 kJ/mol or via the CO–OO intermediate with the energy barrier of 19 kJ/mol. The existence of the twins in porous gold is stabilized by the surface energy.
- OSTI ID:
- 22678909
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 8 Vol. 145; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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