An Atomic Level Understanding of Surface Chemistry and Catalysis (I): Structure and Defects

K. T. Park (Baylor University) and M. H. Pan, V. Meunier, and E. W. Plummer (all CNMS staff)

The atomic level understanding of how an oxide surface acts as a catalyst, photo catalyst, gas sensor, or as a support for metal nanoparticles hinges on a number of challenges related to the accurate determination of the diversity of surface stoichiometry, its structure, and the role of defects. The TiO₂(110) surface, as a prototype transition metal oxide surface, exhibits a number of surface defects, such as oxygen vacancies, hydroxyl groups, and 1-D sub-oxidized strands. All these surface defects have attracted extensive studies in recent years.

Using scanning tunneling microscopy (STM) and first-principles calculations, we have developed a new structural model for surface reconstructions driven by Ti interstitials on TiO₂(110). Contrary to conventional wisdom, the 1x1 periodicity is insufficient to establish the correct surface stoichiometry.

Research by K. T. Park, Baylor University, and M. H. Pan, V. Meunier, and E. W. Plummer, CNMS; “Surface Reconstructions of TiO₂(110) Driven by Suboxides,” Phys. Rev. Lett. 96, 226105 (2006).