Graphene & 2D Materials

Au/TiO2(110) surfaces display extremely high catalytic reactivity. There are many representative models that explain the emerging catalytic activity of Au nanoclusters. It is widely accepted that the perimeter interface of Au/TiO2 is the reaction site for CO oxidation. However, the injection/extraction mechanism of electrons and the reaction process are not clarified by a comprehensive experimental description. In this study, we proposed a new method to simultaneously measuring topography, local contact potential difference (LCPD) and dipole moment distribution on TiO2(110) surface. In the experiment, the DC bias added with ac bias voltage is applied between the tip and sample. Three lock-in amplifiers are used to detect frequency shift of ω, 2ω and3ω. The contact potential difference is numerically calculated from the divided result of ω and 2ω signals and dipole moment is obtained from frequency shift of 3ω. The simultaneously measurement result of topography, LCPD and dipole moment images were obtained on TiO2(110) surface. The details will be reported in the meeting.