Atomic resolution STM imaging of electrochemically controlled reversible promoter dosing of catalysts

SURFACE SCIENCE

卷:369

Article

Makri, M ; Vayenas, CG ; Bebelis, S ; Besocke, KH ; Cavalca, C

关键词: catalysis;    electrochemical methods;    metal-solid electrolyte interfaces;    platinum;    promotion;    scanning tunneling microscopy;    sodium;    surface diffusion;   

DOI  :  10.1016/S0039-6028(96)00911-9

来源: Elsevier

【 摘 要 】

Reversible electrochemically controlled dosing (back-spillover) of sodium on Pt(111) at atmospheric pressure was imaged via atomically resolved STM. The Pt(111) monocrystal was interfaced with a flat polycrystalline sample of beta ''-Al2O3, it Na+ conductor. Application of an electrical current between the Pt(111) monocrystal and a counterelectrode also in contact with the beta ''-Al2O3 Na+-conducting solid electrolyte causes reversible migration (back-spillover and spillover) of sodium, which forms a (12 x 12) hexagonal structure on the Pt(111) surface. In addition to explaining the phenomenon of electrochemical promotion in heterogeneous catalysis, these observations provide the first STM confirmation of spillover phenomena which play a key role in numerous catalytic systems.

【 授权许可】

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