Reactivity of methanol on TiO2 nanoparticles supported on the Au(1 1 1) surface

The reactivity of methanol on TiO2 nanoparticles supported on Au(1 1 1) was examined using temperature-programmed reaction spectroscopy. Since quantitative analytical techniques have shown that the nanoparticles formed by oxidation of sputtered Ti metal on Au(1 1 1) have TiO2 stoichiometry, the reactivity of these particles towards methanol was compared to the reactivity of TiO2(1 1 0), the most thermodynamically stable single crystal surface. The reactivity of the nanoparticles differed from that of the TiO2(1 1 0) stoichiometric surface. Specifically, the nanoparticles produced methane from methanol while the TiO2(1 1 0) stoichiometric surface did not. This difference is attributed to under-coordinated titanium cations present on facets of the nanoparticles, such as those found on {0 1 1}-facetted TiO2(0 0 1) planes, which lead to methane formation. The differences in reactivity towards methanol between the nanoparticles and the extended TiO2(1 1 0) stoichiometric surfaces suggest that the three-dimensional, local structure plays a very significant role in the reactivity of these nanoparticles towards methanol.