Structures and Reactions at Metal/Electrolyte Interfaces at the Atomic Level

Until recently, there had been only few in situ methods available for the structural determination of an electrode surface in solution at the atomic level. Now several recent investigations have demonstrated scanning tunneling microscopy (STM) to be a powerful new technique for in situ characterization, with atomic resolution, of surfaces under potential control. The object of this article is to highlight some of the recent progress made, mainly in the authors' laboratory, on in situ STM with atomic resolution. Several selected topics are focused on, including instrumental and experimental aspects of in situ STM, observation of clean platinum electrode in solution, specifically adsorbed anions (halides, cyanide, sulfate) on metal surfaces, and adsorption of organic molecules (benzene and other small molecules) on clean and iodinemodified electrodes.