Fractional quantum conductance values in Au nanoelectrodes due to hydrogen adsorption M. Díaz a,I,* , M.S. Martín-González a , J.L. Costa-Krämer a a Instituto de Microelectrónica de Madrid, IMM-CSIC, Isaac Newton 8 PTM, 28760 Madrid, Spain. Abstract Hydrogen adsorption in gold nanocontact electrodes in electrochemical solution is experimentally discerned. This is performed with gold nanocontact conductance histograms in an electrochemical environment in which both the electrochemical potential and the electrolyte type are varied. Different salts, acids, and hydrogen peroxide electrolytes are studied. Salts and acids exhibit at negative electrochemical potentials different fractional quantum conductance histograms peaks associated to extra stable structures due to H adsorption while these peaks do not appear for H 2 O 2 where electron transfer between solution and electrodes occurs without hydrogen formation or hydrogen adsorption on the gold electrode .. Keywords: Nanocontact; Gold; Fractional quantum conductance; Electrochemical environment; Hydrogen adsorption 1. Introduction Conductance quantization of metal nanocontacts mechanically formed at RT is a field of considerable interest. Largely studied in UHV [1-2], air [3-5] or immersed in lubricants [6], there has been considerably fewer works of quantized conductance in electrochemical environments [7-13]. In these experiments, different reactions (i.e. I Permanent address: Centro de Física, Instituto Venezolano de Investigaciones Científicas, Apartado 20632, Caracas 1020A, Venezuela. * corresponding author: Tel.: +58 212 504 1585; fax: +58 212 504 1148. E-mail address: marisel@ivic.gob.ve (M. Díaz) Diaz, M., Martin-Gonzalez, M.S., Costa-Kramer, J.L., Surface Science 604 (2010) 1420-1424