SCANNING-TUNNELING-MICROSCOPY H2SO4 0,05M OF A CHEMISORBED SUPERSTRUCTURE PT(100)-C(2X2)S

Saturated sulfur monolayers chemisorbed on Pt(100) single crystal surf aces, prepared in reversible adsorption conditions in gazeous phase, h ave been studied in 0.05 M H2SO4 by scanning tunneling microscopy. A s urface adlattice with c(2x2) periodicity corresponding to the Pt(100)- c(2x2)S interface is observed in the range of cathodic polarization of the sample corresponding to hydrogen adsorption/desorption on clean p latinum and to the double layer region. Intensity maxima and fourfold hollow adsorption sites are deduced for the S adatoms from the images.