Effect of palladium particle size on the appearance of superstructure of graphite in palladium/graphite model catalyst

• Published in: Surface science Vol. 344; no. 3; pp. L1259 - L1263
• Main Authors: Kuwahara, Masashi, Ogawa, Susumu, Ichikawa, Shinichi
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 30.12.1995; Amsterdam Elsevier Science; New York, NY
• Subjects: Carbon; Catalysis; Catalysts: preparations and properties; Chemistry; Clusters; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; General and physical chemistry; Metallic surfaces; Palladium; Physics; Scanning tunneling microscopy; Solid surfaces and solid-solid interfaces; Surface electronic phenomena; Surface structure and topography; Surface structure, morphology, roughness, and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Tunneling; Vicinal single crystal surfaces; Metallic surfaces; Scanning tunneling microscopy; Vicinal single crystal surfaces; Surface electronic phenomena; Clusters; Tunneling; Palladium; Catalysis; Surface structure, morphology, roughness, and topography; Carbon; Fine particle; Superstructure; Size effect; Graphite; Experimental study; STM; Supported catalyst; Surface structure
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(95)00932-9

Scanning tunneling microscopy images of palladium particles supported on highly oriented pyrolytic graphite as a model catalyst in ultra-high vacuum have been observed. We found superstructures on graphite lattice due to electronic interaction between palladium particles and graphite in the vicinity of small two-dimensional palladium particles (lateral size <2 nm, height <0.5 nm). However, such superstructures could not be observed near larger three-dimensional palladium particles (lateral size ∼4 nm, height ∼2 nm). The results indicate the importance of not only the size but also the dimension of metal particles in interaction between palladium and graphite, the nature of which can be interpreted by the difference in electronic properties of atomic and bulk palladium. This has important implications to the understanding of metal-support electronic interaction and its effect on the surface catalytic reactivity of supported metal catalysts.