The catalytic activity of the perimeter sites at the nanoparticle Au/TiO2 interface was observed by IR spectroscopy in the oxidation of CO at low temperatures, where CO adsorbed on the TiO2 support surface was selectively oxidized compared to CO adsorbed on Au. It is found that the O2 molecule is dissociatively activated by chemisorption at the dual Ti4+Au sites at the Au perimeter, with an activation energy of ~0.5 eV.  We have extended this idea to the oxidation of acetic, propionic and butyric acids, where stepwise oxidative attack of the alkyl group can be monitored. For the two higher acids, under oxidation conditions, sequential dehydrogenation steps to produce a C=C bond first occurs at the C2-C3 molecular site, followed by C-C and C-O bond scission to yield the rather exotic Au2=C=C=O (gold ketenylidene) species on the way to CO2 formation. Acetic acid also produces Au2=C=C=O species. The results indicate that high selectivity in the oxidation of carboxylic acids occurs at these Au/TiO2 catalytic sites.

Surface chemistry at dual-perimeter sites on the Au/TiO<sub>2</sub> catalytic surface: Unzipping the alkyl groups in adsorbed carboxylic acids a step at a time

248th National Meeting (2014)

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Surface chemistry at dual-perimeter sites on the Au/TiO2 catalytic surface: Unzipping the alkyl groups in adsorbed carboxylic acids a step at a time

Surface chemistry at dual-perimeter sites on the Au/TiO₂ catalytic surface: Unzipping the alkyl groups in adsorbed carboxylic acids a step at a time