In situ scanning tunneling microscopy as a probe of adsorbate-induced reconstruction at ordered monocrystalline electrodes: carbon monoxide on platinum(100)

Abstract

Abstract : The atomic level structure of ordered Pt(100) electrodes prepared by airhydrogen flame annealing followed by iodine dosing and solution-phase replacement by CO has been examined by in-situ scanning tunneling microscopy. While large (1 x 1) substrate terraces are discernable in the presence of iodine adlayers, subsequent CO adsorption in 0.1 M HC104 yields dense arrays of smaller, 20-40 angstrons (1 x 1) islands. These domains coalesce upon positive alterations in the electrode potential. Parallel in-situ infrared spectroscopic measurements shows that these structural changes are accompanied by an attenuation of bridge-bound CO in the close packed adlayer structure. The bridging CO is speculated to be present at the edges of the (1 x 1) domains, contained within which are predominantly atop coordinated CO.