Determining the Behavior of RuO_x Nanoparticles in Mixed-Metal Oxides: Structural and Catalytic Properties of RuO2/TiO2(110) Surfaces

摘要

In recent years there has been a strong interest in obtaining a fundamental understanding of the chemical behavior of mixed-metal oxides at the nanometer range. Studies involving the deposition of nanoparticles and clusters of VO_x, CeO_x, and WO_x on TiO2(110) and other well-defined oxide surfaces have shown novel structures that have special chemical properties. Dimers of vanadia and ceria have been found on TiO2(110), monomers, trimers, and oligomers of vanadia on CeO2(111), and (WO3)3 clusters on TiO2-(110). In principle, the combination of two metals in an oxide matrix could produce materials with distinct catalytic activity or selectivity. Herein, we use scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and density functional (DF) calculations to study the interaction of RuO2 nanostructures with TiO2(110). Our results show unique wire-like structures for RuO2 that can be easily reduced and reoxidized.