Determination of Molecular Surface Structure, Composition, and Dynamics under Reaction Conditions at High Pressures and at the Solid-Liquid Interface

In the last two decades, surface-science experiments and techniques have been developed to focus on obtaining molecular information under reaction conditions at high pressures (near or above 1 bar) and liquid interfaces. This Minireview describes the results of these studies obtained by surface-sensitive laser spectroscopies, scanning tunneling microscopy, and X-ray spectroscopies usually practiced at a synchrotron light source. The use of model surfaces, single crystals, and monodisperse nanoparticles with variable size (1-10 nm) and shape facilitates meaningful interpretation of the experimental data. These methods allow evaluation of the molecular structures of intermediates, oxidation states of metals, and mobility of adsorbants. New techniques that are likely to make major contributions to the investigation of surfaces under reaction conditions are also discussed. Seeing is believing: Changes in adsorbate and surface structure, composition, and dynamics are observed when such systems are studied under typical reaction conditions (see picture), either at high pressures or in the presence of liquids. Using instruments specifically designed to meet this challenge allows the exploration of interfacial phenomena under realistic conditions at the molecular level. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.