Electrochemistry, Spectroscopy, and Scanning Tunneling Microscopy Images of Small Single-Crystal Electrodes

A general approach to the investigation of electrochemical surface properties is described through several examples. The use of well-defined electrode surfaces obtained from small single-crystal beads accurately oriented in careful electrochemical experiments allows us to obtain an initial picture of the system under scope. The techniques used in the proposed examples are cyclic voltammetry, the most commonly used technique in surface electrochemistry, and the CO displacement technique, which leads to the determination of the potential of zero total charge. This is a key magnitude in adsorption studies that provides valuable criteria for coulo-metric coverage determinations. This initial picture is then completed by using other techniques such as in situ Fourier transform infrared spectroscopy and scanning tunneling microscopy. These new data improve our knowledge on the system under study. As illustrating examples, we present the influence of anion and hydrogen adsorption of CO_ad _{oxidation at Pt(lll) and NOad reduction at Pt(100). The study of irreversibly adsorbed Br adlayers on Pt(lll) and Pt(100) and urea adsorption on Pt(100) are also summarized.}