In this work, nano-faceted metal surfaces have been used as model catalysts for various reactions and as nano-templates for growth of metallic nanostructures. Faceting of metal surfaces is a form of self-assembly on the nanometer scale and occurs when an initially planar surface of a metal single crystal converts to a nano-faceted surface with �hill and valley� structure exposing new crystal faces on the nanometer scale when covered by gas or metal followed by annealing in vacuum or upon annealing in gas. Annealing Ir(210) in O2 leads to formation of nano-faceted O/Ir(210) that consists of three-sided pyramids exposing (311), (31-1) and (110) faces on each pyramid, and clean faceted Ir(210) can be routinely prepared in-situ by reaction with hydrogen at 400K. We have carried out a series of reactions on clean planar Ir(210) and clean faceted Ir(210) with different facet sizes to probe for structure sensitivity and size effects on the nanometer scale. Annealing Ru(11-20) in NO2 produces ridge-like faceted Ru(11-20) surface exposing (10-11), (10-1-1), (01-11) and (01-1-1) faces. Faceted O/Ru(11-20) facilitates growth of Au nanoclusters at room temperature which preferentially nucleate within valleys of the faceted surface. This work is supported by DOE (Contract No. DE-FG02-93ER14331).

Nanofaceted metal surfaces: Catalysis and nanotemplates

245th National Meeting (2013)

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