title: CO-induced smoluchowski ripening of Pt cluster arrays on the graphene/Ir(111) moiré.
abstract: Regular Pt cluster arrays grown on the moiré template formed by graphene on Ir(111) were tested for their stability with respect to CO gas exposure. Cluster stability and adsorption-induced processes were analyzed as a function of cluster size, with in situ scanning tunneling microscopy and X-ray photoelectron spectroscopy. Small clusters containing fewer than 10 atoms were unstable upon CO adsorption. They sintered through Smoluchowski ripening-cluster diffusion and coalescence-rather than the frequently reported Ostwald ripening mediated by metal-adsorbate complexes. Larger clusters remained immobile upon CO adsorption but became more three-dimensional. Careful analysis of the experimental data complemented by ab initio density functional theory calculations provides insight into the origin of the CO-induced Pt cluster ripening and shape transformations.
authors: II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany. gerber@ph2.uni-koeln.de
authors: Timm
authors: T
authors: Gerber
authors: Jan
authors: J
authors: Knudsen
authors: Peter J
authors: PJ
authors: Feibelman
authors: Elin
authors: E
authors: Grånäs
authors: Patrick
authors: P
authors: Stratmann
authors: Karina
authors: K
authors: Schulte
authors: Jesper N
authors: JN
authors: Andersen
authors: Thomas
authors: T
authors: Michely