Scanning tunneling microscopy and electrochemical study of the surface structure of Pt(10,10,9) and Pt(11,10,10) electrodes prepared under different cooling conditions

The effect of three surface electrochemical preparation techniques for sing le crystal surfaces on two platinum stepped surfaces [Pt(10,10,9) and Pt(11 ,10,10)] has been investigated by scanning tunneling microscopy and cyclic voltammetry. The preparation techniques consisted of a thermal treatment fo llowed by a cooling step in (a) a hydrogen+argon atmosphere, (b) air (c) io dine vapor+air. For Pt(10,10,9) and Pt(11,10,10) surfaces, the hydrogen+arg on treatment provides surfaces that have a very narrow distribution of terr ace widths around the nominal value and monatomic steps. On the other hand, facetted surfaces with terrace widths and steps four to five times their n ominal values are obtained when the cooling is in the presence of iodine va por. The air treatment generates surfaces in which the terrace width is not as uniform as in the H-2+Ar case and some kink sites are created. The chan ges in the surface topography can be followed in the voltammetric profile o f the surfaces recorded in a sulfuric acid solution. (C) 1999 Elsevier Scie nce B.V. All rights reserved.