Nano Pinstripes: TiO2 Nanostripe Formation by Nanoparticle-Mediated Pinning of Step Edges

The present scanning tunneling microscopy study describes the high-temperature growth of TiO2 nanostripes with tunable width, orientation, and spacing, mediated by thermally stable micellar Pt and Au NPs deposited on TiO2(110). This phenomenon could not be explained by spillover effects but is based on the preferential stabilization of [11̅0] step edges on TiO2(110) by the metal NPs. Contrary to the behavior of physical-vapor-deposited NPs, which are known to move toward step edges upon annealing, our micellar NPs remain immobile up to 1000 °C. Instead, the mobility of TiO2 step edges toward the micellar NPs, where they become stabilized, is observed. Our findings are relevant to the technological application of nanostructured materials in the fields of catalysis, molecular electronics, and plasmonics.