Using scanning tunnelling microscopy and density functional theory simulations, the diffusion of alkoxy species formed by the dissociation of alcohols on bridge-bonded oxygen vacancies on TiO2(110) was studied. At elevated temperatures (≥400K), the sequential isothermal scanning tunnelling microscopic images showed that mobile bridge-bonded oxygen vacancies mediated the diffusion of alkoxy species by providing space for alkyl-group-bearing bridge-bonded oxygen atoms to diffuse. The experimental findings were further supported by simulations that showed that bridge-bonded oxygen vacancy diffusion was the rate-limiting step in the overall diffusion mechanism.

Vacancy-Assisted Diffusion of Alkoxy Species on Rutile TiO2(110). Zhang, Z., Rousseau, R., Gong, J., Li, S.C., Kay, B.D., Ge, Q., Dohnálek, Z.: Physical Review Letters, 2008, 101[15], 156103